22 November 2004 Multisession management in spoken dialogue system Hoá NGUYEN & Jean CAELEN.

22 November 2004

Multisession Multisession management in management in spoken dialogue spoken dialogue

systemsystem

Hoá NGUYEN & Jean CAELEN

BP 53 - 38041 Grenoble Cedex 9 - FranceCNRS - INPG - UJF

Communication Langagière etInteraction Personne-Système

GEODGroupe d'Etude sur l'Oral et le Dialogue

22 November 2004 Hoá Nguyen & Jean Caelen 2

Plan1. Motivation2. Basic principles3. Multisession dialogue modeling4. Multisession dialogue management5. Experimentation6. Conclusion


1. Motivation Context : PVE (Portail Vocal d’Entreprise) project

Voice service in a mobile situation : very useful for applications such as information requests, confirmation of an urgent request, secretarial work at distance, etc.

Conditions of success: Complete service for resolving problem in a face-to-face

situation (for instance room reservation service), Requirement of capability to resolve the conflict

resources of several users in order to obtain a good compromise between them.

Needs : dialogue management between multiple users and the system using short spoken session in NL, with complex utterances.


2. Basic principlesArchitecture for a spoken dialogue system

Dialogue model based on :

• Speech acts theory,

• General games theory using

Dialogue goal,

Dialogue strategies.


Speech act Fp = Illocutionary force on logical content Illocutionary force: an assert, a denial, a

promise, a request, etc.

Example: I would like book a conference's room

FS[FirstName(jean)&LastName(caelen)]&FF[Action(reserve)&RoomName(x)]

Illocutionary force logical content (p) Concept


Dialogue goal Goal: a state of the task or a mental state that

user wants to reach (for example: to organize a meeting, to obtain an information)

Dialogue goal: goal sustained during a session Dialogue agenda: hierarchy of goals to perform a

task.

Ex: "I would like to reserve a room please" -> Speech act: FF[Action(reserve)&RoomName(x)]-> dialogue goal: ?RESERVE-> dialogue agenda: RESERVE[RoomName:Size:Material]


Dialogue strategy (1/2) Dialogue strategy: the way to handle the talking turns

between speakers to lead a dialogue goal. Typology:Non-inference strategies: Speaker does not need to know the goal of

his partner. - Directive strategy: consists in keeping the initiative to drive the

dialogue: maintaining the exchange goal and keeping the initiative, imposing a new goal.

- Reactive strategy: consists in delegating the initiative to the partner either by making him to endorse his goal, or by adopting his goal.

- Constructive strategy: consists in moving the current goal in order to invoke a detour, for example to make it to notice an error, make a quotation, undo an old fact...


Dialogue strategy (2/2)Inference strategies: the two partners have a perceptive knowledge of

their respective goals + a shared initiative.- Cooperative strategy: consists in adopting the goal of his partner by

proposing one (or many) solution which brings them the most relevant way to achieve their goal.

- Negotiated strategy: involved while the goals are incompatible and the speakers want to minimize the concessions. The negotiation is expressed by argumentative sequences (argumentation/refutation) with the proposal for a sub-optimal solution until convergence or acknowledgement of failure.


3. Multisession dialogue modelingSituation: during a dialogue, the user D interacts with the system S

for resolving the goal bD. We suppose bD cannot be reached because it is in conflict with others goals previously satisfied by others users.

Ex:D: Hello, I am D. Could you book me the Lafayette room for tomorrow from 10h to 12h, please?S: I’m sorry Mr. D, this room was already booked by Mr. P1 from 9h to 11h and by Mr. P from 11h to 13h. However, the Aquarium room is available tomorrow morning...D: No, it’s too small. Tell them I need the Lafayette and could they leave room for me.S: ...

This case needs a negotiation process to resolve the conflict between these users.


Definitions (1/3) Dialogue goal in conflict bf: the dialogue goal

aimed by the requester D is in conflict with the one already satisfied by the user P: bF = (bD, bP)

Tree of dialogue goals in conflict: more generally the goal bD is possibly in conflict with n satisfied goals of n other users (patients) (P1,…Pn) related by AND/OR operators. This set of conflict goals (bF1, bF2, … , bFn) makes a AND-OR binary tree of dialogue goals in conflict with bD, noted TF.


Definitions (2/3)

A sample tree of dialogue goals in conflict

AND

AND

OR AND

OR

bF1 bF2

bF3

bF4 bF5

bF6

- Path for traveling PF: is a path leading from leafs to the root in TF in respect to all AND/OR conditions along this tree. The set of their leafs makes a list of goals in conflict PF = {bFi bFj …}. For example, in tree TF of sample, there are paths like {bF1bF2 bF4 bF6}, {bF3bF5bF6}, …


Definitions (3/3) Dialogue session: a set of interactions

between a single user and the system.

Multisession dialogue: In case of bD is in

conflict with multiple patients, a set of discontinuous dialogue sessions must be invoked to resolve the conflict. This set defines a multisession dialogue. Multiple users should be committed in a multisession dialogue.


Multisession coordinationA multisession dialogue is divided into three phases: Emergent phase: a new goal bD expressed by D falls in

conflict. On request of D, S puts bD in the pending queue and plans the process of conflict resolution.

Negotiation phase: contains possibly several sessions. As long as bD has not been reached yet and there is still a no-traveled path for traveling in the tree, S has to contact the patients to negotiate with each of them for a good compromise towards bD. This process will be stopped when either bD is reached or S has scanned all possible paths in TF and there are no more paths for traveling, and S has to abandon bD.

Notification phase (final session): S informs D about the negotiation result (bD reached or abandoned). Then D could agree or refuse it.


4. Multisession management The multisession dialogue management is done

conjointly by the dialogue manager and the task manager: Task manager: identifies all the goals in conflict, builds

the tree TF and sends it to the dialogue manager,

Dialogue manager: schedules the session and manages TF in cooperation with the task manager.


Dialogue manager (1/3)

Finds the best strategy exploring the tree of goals in conflict TF in order to obtain the best process of negotiation

Coordinates the set of the sessions in a “multi-session dialogue” for allowing a coherent dialogue


Dialogue manager (2/3) Examples of rules concerning Attitudes of user

towards TF: FD(bD) => FS

S(TF) : S informs about the problem to D,

FFSD(TF) => =directive FS

S(explications TF) : S explains to D the conflict provided by TF,

FFD(TF) => =negotiated -bD FA

S(TF) : S changes the strategy into negotiation, and performs TF if D requests to do it.

FFD(¬TF) => =cooperative FF

S(b’D) : If D do not want to resolve the conflicts, then S should offer another solution representing by the repaired goal b’D and apply the cooperative strategy.


Dialogue manager (3/3) Expert-contact module:

Finds the best no-traveled path PF in the tree of goals in conflict TF as regard as AND/OR conditions.

Schedules the contact to each patient related to PF regarding constraints on the relevance or on the time contact efficiency (e.g. minimizing total duration of phone calls), etc.

Determines the best strategy to contact him role(P) > role(D): =cooperative,

role(P) <= role(D): =directive.


Task manager Identifies all possible conflicts and then

builds the tree of goals in conflict TF, Controls the session trigger for each

session in a general negotiation process and notifies the end of the session.


5. Experimentation (1/3)

Expert-Contact

Emergent phase

AgendabP1=reserved(lafayette,d,9h,2h,dupont)bP2=reserved(lafayette,d,11h,2h,dupaint)

D: Hello, I am D. Could you book me the Lafayette room for tomorrow from 10h to midday, please?S: I’m sorry Mr. D, this room was already reserved by Mr. P1 from 9 to 11h and by Mr. P2 from 11 to 13. However, the Aquarium room is available tomorrow…D: No, it’s too small. Tell them I need the Lafayette and could they leave room for me.S: OK, I’ll contact them and I’ll keep you up to date.

?bD=Name(d)^Room(lafayette)^Date(d=tomorrow)^hour(10h) ^duration(2h) TF = {bF1 ^ bF2}bF1 = (b, bP1)bF2 = (b, bP2)-bD, FF(TF)

15h30, 17/05/2004



Expert

S: hello, are you Mr. P1?P1: yes,S: I’m contacting you about the Lafayette reservation tomorrow morning. Mr. D would absolutely have it, because its meeting is very important, so could you leave him this room, please?P1: OK, but put back my reservation to the next day.S: That’s great. You’ll have Lafayette at the same time the day after tomorrow. Thank you very much.

Negotiation process

S: hello, are you Mr. P2?P2: yes, P2 is speaking…S: Mr. D has an important meeting tomorrow morning. So could you leave the Lafayette for him, please?P2: um… OK, please book the Aquarium room at the same time for me and I don’t want any more change...S: Thank you for your generosity. You’ll have the Aquarium tomorrow from 11h to 13h.

15h40, 17/05/2004

?bF1

P1

‡bF1

?bF2

P2

‡bF2

ET

†bD

15h35, 17/05/2004



Expert

S: Hello, Mr. D?D: Yes, it’s meS: Mr. P1 and P2 have already agreed to leave the Lafayette for you at 9h for tomorrow.D: That’s very nice, thank you. And inform also all member of PVE project for me please.S: OK, I’ll call them immediately. Good-bye Mr. D.

Notification phase

†bD

D

‡bD

15h45, 17/05/2004


6. Conclusion Multisession dialogue handling in a spoken

dialogue system becomes now a necessary requirement in increasing the negotiation capability of the system,

We experimented successfully a conversational agent for resolving the conflicts between several users in a voice portal (for the meeting organization service)

22 November 2004 Multisession management in spoken dialogue system Hoá NGUYEN & Jean CAELEN.

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