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

22 November 2004Hoá Nguyen & Jean Caelen 2 Plan 1. Motivation 2. Basic principles 3. Multisession dialogue modeling 4. Multisession dialogue management 5. Experimentation 6. Conclusion

22 November 2004Hoá Nguyen & Jean Caelen 3 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.

22 November 2004Hoá Nguyen & Jean Caelen 4 2. Basic principles Architecture for a spoken dialogue system Dialogue model based on : Speech acts theory, General games theory using Dialogue goal, Dialogue strategies.

22 November 2004Hoá Nguyen & Jean Caelen 5 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 F S [FirstName(jean)&LastName(caelen)]&F F [Action(reserve)&RoomName(x)] Illocutionary force logical content (p) Concept

22 November 2004Hoá Nguyen & Jean Caelen 6 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]

22 November 2004Hoá Nguyen & Jean Caelen 7 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...

22 November 2004Hoá Nguyen & Jean Caelen 8 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.

22 November 2004Hoá Nguyen & Jean Caelen 9 3. Multisession dialogue modeling Situation: during a dialogue, the user D interacts with the system S for resolving the goal b D. We suppose b D 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.

22 November 2004Hoá Nguyen & Jean Caelen 10 Definitions (1/3)  Dialogue goal in conflict b f : the dialogue goal aimed by the requester D is in conflict with the one already satisfied by the user P: b F = (b D, b P )  Tree of dialogue goals in conflict: more generally the goal b D 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 (b F1, b F2, …, b Fn ) makes a AND-OR binary tree of dialogue goals in conflict with b D, noted T F.

22 November 2004Hoá Nguyen & Jean Caelen 11 Definitions (2/3) A sample tree of dialogue goals in conflict AND OR AND OR b F1 b F2 b F3 b F4 b F5 b F6 - Path for traveling P F : is a path leading from leafs to the root in T F in respect to all AND/OR conditions along this tree. The set of their leafs makes a list of goals in conflict P F = {b Fi  b Fj …}. For example, in tree T F of sample, there are paths like {b F1 b F2  b F4  b F6 }, {b F3 b F5 b F6 }, …

22 November 2004Hoá Nguyen & Jean Caelen 12 Definitions (3/3)  Dialogue session: a set of interactions between a single user and the system.  Multisession dialogue: In case of b D 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.

22 November 2004Hoá Nguyen & Jean Caelen 13 Multisession coordination A multisession dialogue is divided into three phases:  Emergent phase: a new goal b D expressed by D falls in conflict. On request of D, S puts b D in the pending queue and plans the process of conflict resolution.  Negotiation phase: contains possibly several sessions. As long as b D 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 b D. This process will be stopped when either b D is reached or S has scanned all possible paths in T F and there are no more paths for traveling, and S has to abandon b D.  Notification phase (final session): S informs D about the negotiation result (b D reached or abandoned). Then D could agree or refuse it.

22 November 2004Hoá Nguyen & Jean Caelen 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 T F and sends it to the dialogue manager, Dialogue manager: schedules the session and manages T F in cooperation with the task manager.

22 November 2004Hoá Nguyen & Jean Caelen 15 Dialogue manager (1/3) Finds the best strategy exploring the tree of goals in conflict T F 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

22 November 2004Hoá Nguyen & Jean Caelen 16 Dialogue manager (2/3)  Examples of rules concerning Attitudes of user towards T F : F D (b D ) => F S S (T F ) : S informs about the problem to D, F FS D (T F ) => =directive  F S S (explications T F ) : S explains to D the conflict provided by T F, F F D (T F ) => =negotiated  -b D F A S (T F ) : S changes the strategy into negotiation, and performs T F if D requests to do it. F F D (¬T F ) => =cooperative  F F 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.

22 November 2004Hoá Nguyen & Jean Caelen 17 Dialogue manager (3/3)  Expert-contact module: Finds the best no-traveled path P F in the tree of goals in conflict T F as regard as AND/OR conditions. Schedules the contact to each patient related to P F 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.

22 November 2004Hoá Nguyen & Jean Caelen 18 Task manager  Identifies all possible conflicts and then builds the tree of goals in conflict T F,  Controls the session trigger for each session in a general negotiation process and notifies the end of the session.

22 November 2004Hoá Nguyen & Jean Caelen Experimentation (1/3) Expert-Contact Emergent phase Agenda b P1 =reserved(lafayette,d,9h,2h,dupont) b P2 =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. ?b D =Name(d)^Room(laf ayette)^Date(d=tomorro w)^hour(10h) ^duration(2h)  T F = {b F1 ^ b F2 } b F1 = (b, b P1 ) b F2 = (b, b P2 ) -b D, F F (T F ) 15h30, 17/05/2004

22 November 2004Hoá Nguyen & Jean Caelen Experimentation (2/3) 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 ?b F1 P 1 ‡b F1 ?b F2 P 2 ‡b F2 ET †bD†bD 15h35, 17/05/2004

22 November 2004Hoá Nguyen & Jean Caelen Experimentation (3/3) Expert S: Hello, Mr. D? D: Yes, it’s me S: 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 †b D D ‡b D 15h45, 17/05/2004

22 November 2004Hoá Nguyen & Jean Caelen 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)