Abstract:
A system and method for a dialog system which provides for a user to carry on a dialog with dialog experts having different capabilities, during an existing dialog session. A terminal device may be connected to a special switching device, which, in dependence upon a communicated user statement, may provide the user with the optimal system statement from a multiplicity of system statements received from various dialog devices.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a dialog system for a man-machine interaction, which the user can use to communicate with various dialog experts. 
   BACKGROUND INFORMATION 
   Automated, goal-directed, interactive voice-communication systems or information systems operable by natural speech are available, which are able to access databases and which lead the user, through targeted questions, to desired information, to a transaction or the like. The dialog is carried out in a very rigid sequence of system questions and user responses. Examples of such goal-directed interactive voice-communication systems are, inter alia, telephone banking systems or card-reservation systems. The goal-directed dialog systems include targeted querying of the user information necessary for a specific application. 
   However, some users have indicated that systems of this kind are not flexible enough in their current state of development. This is because user statements which are not modeled in the application of the particular interactive voice-communication system, cannot be interpreted and can lead to irresolvable dialog situations. These irresolvable dialog situations involve the interactive voice-communication system entering into a state where the same text is always output or the connection is interrupted. 
   In addition to such goal-directed dialog systems, there are also so-called chat dialog systems or ‘chat bots.’ A chat bot gives the user the impression that the user can carry on a conversation with it about nearly any subject. Such a “chat-oriented” dialog system supports a very free formulation of questions, responses, and explanations, on the user side, so that a chatty-type dialog can take place between man and machine. In such a chat-oriented dialog system, any user inputs at all are answered without being rejected. However, a chat-oriented dialog system is not suited for conducting a goal-directed informational dialog where it is necessary, for example, to query specific user information before the corresponding information can be found and output. For that reason, chat-oriented dialog systems or chat bots are sometimes criticized by users as not being proficient enough, since neutral and pointless system remarks are sometimes produced in response to non-modeled user statements. Thus, in some available systems, a user was only able to be connected directly and inflexibly to a goal-directed dialog expert or to a chat-oriented dialog expert or chat bot. 
   SUMMARY OF THE INVENTION 
   Exemplary embodiments and/or exemplary methods of the present invention provide users with a dialog system characterized by greater efficiency and flexibility. 
   Exemplary embodiments and/or exemplary methods of the present invention provide that a user will no longer have to communicate in a rigid and inflexible manner in a session with one single dialog system. Instead, the user may make contact with a special switching device, which, in dependence upon his user statement, provides him with the optimal system statement from a multiplicity of system statements from various dialog devices. User and system statements discussed herein may be both responses and questions transmitted by a terminal device assigned to the user or by dialog devices. It can be, therefore, the task of the switching device to receive a user statement produced by the user, to relay it to a plurality of dialog devices, to wait for the system statements from the dialog devices, and, in accordance with a defined logic, to output the most suitable system statement to the user. 
   Some dialog devices may be generally available, goal-directed dialog devices and chat bots, which support an interaction with a user in the form of dialogs. Such dialog devices herein may also be referred to as dialog experts. 
   Exemplary embodiments and/or exemplary methods of the present invention provide a dialog system for a man-machine interaction, which has at least one terminal device where a user may input a user statement. The user statement may be input into the terminal device, for example, by voice and by using a microphone. It may also be entered via a keyboard. To achieve a high level of user friendliness, the user statement may also be entered in natural speech form, i.e., in natural sentences and questions. However, the manner in which a user statement is entered may not be essential for the present invention. At least one first switching device may be also provided, which is able to be connected to the terminal device. Assigned to the first switching device may be a plurality of dialog devices, which, in an available manner, are able to receive, analyze, and process user statements, in order to subsequently generate an appropriate system message. A system message includes a system statement intended for the terminal device, an identification code identifying the particular dialog device, and/or an identifier. The identifier may correspond to a hard decision, which, for example, merely signals to the first switching device whether a dialog device may or may not generate a system statement in response to a user statement. The identifier may also correspond to a soft decision, i.e., it indicates which performance or quality a generated system statement has. This means that it indicates the degree to which the generated system statement applies to the previously analyzed user statement. 
   In exemplary embodiments and/or exemplary methods, to be able to offer the user an optimal dialog, the first switching device may have a first device for relaying a user statement coming from a terminal device to at least some of the assigned dialog devices, as well as a second device, which, functioning in response to the system messages received from the dialog devices, selects a system message, and transmits the system statement contained therein to the terminal device. 
   In exemplary embodiments and/or exemplary methods of the present invention, to be able to communicate an optimized system statement, which may be a system response or a system question, to the user, the second device of the first switching device may have a detector device for capturing the identifier and the identification code which are received in a system message. In addition, a memory device for storing a priority list may be included in the second device. Using the priority list and the output signal from the detector device, a decision device, which may be separately designed or integrated with the detector device, may select the system statement of a specific dialog device, in order to relay it to the terminal device. The priority list may contain the identification codes of each dialog device assigned to the first switching device, as well as the priority assigned to the particular dialog device. 
   In exemplary embodiments and/or exemplary methods of the present invention, since the system messages received by the dialog devices may not be able to be simultaneously processed in the first switching device, for example, because the system messages from various dialog systems arrive at different points in time, the second device of the first switching device may be provided with a memory for storing the received system messages or also only the system statements. 
   In exemplary embodiments and/or exemplary methods of the present invention, the decision device may be designed, for example, to apply the identification code of the selected dialog device as a memory address to the memory. This may enable the system statement to be transmitted to the terminal device. 
   In exemplary embodiments and/or exemplary methods of the present invention, to be able to connect the terminal device to dialog devices of various manufacturers, and various dialog devices to the existing dialog system without substantial outlay, a user interface may be assigned to the terminal device to provide a first communication protocol and/or data format for exchanging data with the first switching device. Moreover, each dialog device may have an interface for preparing a second communication protocol and/or data format for exchanging data with the first switching device. Also, the first device of the first switching device may have a conversion device for converting the first communication protocol and/or data format into the second communication protocol and/or data format and vice versa. 
   In exemplary embodiments and/or exemplary methods of the present invention, in order to avoid the situation, for example, where a user has to wait an unreasonable length of time for a response from a dialog device, a timer may be provided in the first switching device to monitor the receipt of a system message within a preset time span. For example, following expiration of the preset time span, the user statement may be transmitted once more by the first switching device to the dialog devices, or, for example, the first switching device considers only the system statements received within the preset time span. 
   In exemplary embodiments and/or exemplary methods, both the first switching device and the dialog devices involved in a corresponding dialog may record the frequency with which their system statements are transmitted to the terminal device. For this, the first switching device may have a confirmation device, for example, which transmits a confirmation message to the dialog device whose system statement has been relayed to the terminal device. Accordingly, at least some of the dialog devices may have a device for counting and analyzing the confirmation messages received. In this manner, it may be possible, for example, that a goal-directed dialog device, which has no longer been included in the dialog for a specific time span, generates a predefined, goal-directed system message, which is switched through by the detector device and the decision device in the first switching device, directly to the terminal device. 
   In exemplary embodiments and/or exemplary methods of the present invention, by recording the frequency with which system statements are relayed to a dialog device, the priority list may be dynamically adapted, during an existing dialog, to the dialog sequence. For example, a dialog device may be assigned a higher priority in the priority list afterwards, when, for example, the system statements of this dialog device are relayed very frequently to the terminal device. It is also possible that the user himself is able to change the priority list, by informing the first switching device of the type of dialog desired. In this manner, from the outset, a higher priority in the priority list may be assigned to the appropriate dialog device, in dependence upon the dialog desired by a user. 
   In exemplary embodiments and/or exemplary methods of the present invention, to further optimize the dialog system, a sub-switching device may be assigned to each dialog device, it being possible, in turn, for a plurality of sub-dialog devices to be assigned to each sub-switching device. For this purpose, the sub-switching device may have a device, which transmits a user statement relayed by the dialog device, to at least some of the assigned sub-dialog devices. In addition, a device may be provided, which, functioning in response to the system messages received by the sub-dialog devices, selects a system message and transmits it to the first switching device. Following this pre-weighting of system messages, in the manner described above, the first switching device then may select the system message whose system statement is to be transmitted to the terminal device. 
   In exemplary embodiments and/or exemplary methods of the present invention, the performance and precision of the dialog system may be enhanced by connecting a second switching device between the terminal device and a plurality of first switching devices. The second switching device may have a first device for relaying a user statement coming from the terminal device to at least some of the first switching devices. In addition, a second device may be provided, which functioning in response to the system messages coming from the first switching device(s), to select a system message and transmit the system statement contained therein to the terminal device. In this approach, the first switching device must be designed for relaying a selected system message to the second switching device. That is, the first switching device not only may transmit the system statement but also may transmit the identifier from the dialog device in question that is integrated in the system message and the identification code. 
   In exemplary embodiments and/or exemplary methods of the present invention, the switching devices and/or sub-switching devices may be designed to be able to inform the dialog devices or sub-dialog devices in question, of the dialog end. In this connection, the end of the dialog may be initiated by a specific dialog device, sub-dialog device, or by the user himself, for example, by hanging up the telephone receiver. 
   In exemplary embodiments and/or exemplary methods of the present invention, the dialog system includes at least one terminal device where a user may input a user statement. In addition, a plurality of interconnectible dialog devices may be provided, which may be connected to the terminal device. Each dialog device may have a device for receiving and analyzing a user statement generated by the terminal device, as well as a device for generating a system message in dependence upon the analyzed user statement. Moreover, a decision device may be provided for relaying the user statement to another dialog device or for relaying a generated system message to the terminal device in dependence upon the analyzed user statement. For example, the dialog devices may be connected in series, so that one dialog device always relays a user statement to the dialog device that follows next when it itself is not able to generate a system message in response to a received user statement. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a dialog system, including a plurality of various dialog experts, in which the present invention is implemented. 
       FIG. 2  illustrates another embodiment of a dialog system, in which the present invention is implemented. 
       FIG. 3  depicts another embodiment of a dialog system according to the present invention, including dialog experts connected in series. 
       FIG. 4  shows a basic block diagram of a switching device in accordance with the present invention, according to  FIG. 1 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows an exemplary embodiment of a dialog system, which, for purposes of a better and simpler representation, is only shown in extract. Thus, only two terminal devices  10  and  20  are shown, which are each linked via a user interface  12  or  22  to a subscriber exchange  30 . User interfaces  12  and  22  provide a communications protocol and/or data format, via which the terminal devices may exchange data with a switching device  40 . For example, terminal device  10  is a telephone, and terminal device  20  a multimodal terminal. Via subscriber exchange  30 , a user may establish a connection to switching device  40  by selecting a specific address. The switching device is described in greater detail in the following. Assigned to switching device  40  are a plurality of different dialog experts, of which merely the two dialog experts  50  and  60  are shown. In the following description, it may be assumed that dialog expert  50  is suited for a goal-directed dialog, for example, for a directory assistance, and that dialog expert  60  represents a so-called chat bot for a chat-oriented dialog. 
   Dialog experts  50  and  60  each have interfaces  52  and  62 , respectively, which provide a specific communications protocol and/or data format for exchanging data with switching device  40 . 
   An exemplary switching device  40  is shown in  FIG. 4 . Switching device  40  has a conversion device  44 , which adapts the communications protocol and/or data format between interfaces  52  and  62  of dialog experts  50  and  60 , respectively, and user interfaces  12  and  22  of terminal devices  10  and  20 , respectively. This makes it possible for any desired terminal devices to be connected to any desired dialog experts. In addition, switching device  40  shown in  FIG. 4  has a detector device  43 , which is provided for recording system messages that may be generated by dialog experts  50  and  60 . A system message is composed, for example, of the actual system statement intended for a terminal device, an identification code of the particular dialog expert, and of an identifier. The identifier may correspond to a hard decision which merely signals that the system message includes a system statement. The identifier may also correspond to a soft decision, in that it indicates the quality of a system statement with respect to an analyzed user statement. For a hard decision, the identifier may be represented by the binary digit “0”, i.e., no system statement has been generated, or by a “1”, i.e., a system statement has been generated. When an indication of the quality of the system statement is provided, the identifier may represent a number between 0 and 100, in order to define the measure of the quality. Thus, for example, number  100  corresponds to a system statement which applies optimally to the analyzed user statement. 
   Detector device  43  may be able to capture the identifier and identification code of a received system message, and feed them to a decision device  42 . In addition, decision device  42  is connected to a memory  46 , in which a priority list is stored. In the present example, the priority list includes the identification codes of the two dialog experts  50  and  60 , as well as the priorities assigned to the two dialog experts. For example, dialog expert  50  enjoys a higher priority than dialog expert  60 . Detector device  43  may be linked to a memory  45  in which the entire system message or merely the system statement contained in a system message is stored. Decision device  42  is likewise connected to memory  45 , in order to be able to select predefined system statements to be relayed to a terminal device. To this end, decision device  42  has a logic, which, in dependence upon the priority list in memory  46  and the identifier captured in a system message by detector  43 , is able to decide whether the system message of dialog expert  50  or of dialog expert  60  should be relayed to a terminal device. In addition, decision device  42  may generate a confirmation message for the dialog expert, whose system statement has been relayed to a terminal device. Via a switch  47 , the generated confirmation message is placed on the output line which leads to the appropriate dialog expert. 
   A control unit  41 , which monitors and controls switching device  40 , may, for example, log how often a system statement of the two dialog experts  50  and  60  has been relayed during a dialog session to the corresponding terminal device. 
   In addition, dialog experts  50  and  60  may each have a counting and evaluation device  54  and  64 , respectively, to determine the frequency of the system messages generated by them and relayed to a terminal device during a dialog session with a terminal device. Counting and evaluation devices  54  and  64  also may assure that a dialog expert is able to generate a predefined, preferably goal-directed system statement, when, within a preset time span, no more system statement from it has been relayed by switching device  40  to a terminal device. This predefined system statement may be immediately switched through by the switching device to the terminal device. 
   Depending upon how many generated system statements have been relayed by dialog experts  50  and  60  to the particular terminal device, control unit  41  may undertake an adaptation of the priority list in memory  46 . Should it turn out, namely, during a dialog session that the system statements from dialog expert  60  are made available much more frequently than from dialog expert  50 , then, during this dialog session, dialog expert  60  may be assigned a higher priority than dialog expert  50 . It is likewise conceivable to render possible a user-controlled adaptation of the priority list for a specific dialog session. If, for example, the user merely wants to “chat”, and no goal-directed information is needed, then, via his terminal device, he may transmit a control parameter to this effect to switching device  40 , whereupon control unit  41  raises the priority of dialog expert  60  with respect to dialog expert  50 . The priority list may also or instead reflect the usage of the participating dialog experts, the highest priority being assigned to the dialog expert having the lowest usage. For this purpose, each dialog expert may determine his usage and make this available to the assigned switching device. Moreover, the switching exchange itself could estimate the usage of the participating dialog experts on the basis of the corresponding response times. 
   To be able to offer the user a higher dialog quality, a sub-switching device  70  may be assigned to dialog expert  50 , and a sub-switching device  80  to dialog expert  60 . Three further dialog experts,  90 ,  191 , and  90  are assigned to sub-switching device  70 , whereas three other dialog experts  93 ,  94  and  95  are assigned to sub-switching device  80 . In principle, sub-switching devices  70  and  80  may be designed similarly to switching device  40 . Thus, sub-switching devices  70  and  80  each have devices  72  and  82 , respectively, which retransmit the user statement relayed by the particular dialog expert  50  or  60  to at least some of the assigned sub-dialog experts  90  through  92  and  93  through  95 , respectively. Conversely, the design of sub-switching devices  70  and  80  may also include detector and decision devices  74  and  84 , respectively, which, functioning in response to the system messages received from sub-dialog experts  90  through  92  and  93  through  95 , respectively, select a system message and transmit this directly or via assigned dialog experts  50  or  60  to switching device  40 . 
     FIG. 2  shows another exemplary embodiment of a dialog system which may offer a user an improved dialog. Two terminal devices  10  and  20  are connected, in turn, via corresponding user interfaces  12  and  22 , respectively, to a subscriber exchange  30 . Subscriber exchange  30  may connect terminal devices  10  and  20  to a main switching device  100 , which is connected, in turn, to a plurality of switching devices. To simplify the illustration, only three switching devices  40 ′,  40 ″ and  40 ′″ are shown. Switching device  40 ′ is connected, for example, to two dialog experts  50 ′ and  60 ′, switching device  40 ″ to dialog experts  50 ″ and  60 ″, and third switching device  40 ′″ to dialog experts  50 ′″ and  60 ′″. Main switching device  100  has a transmission device  102 , which relays the user statement coming from a terminal device to at least some of switching devices  40 ′,  40 ″ and  40 ′″. Switching device  40  according to  FIG. 1  differs from switching devices  40 ′,  40 ″ and  40 ′″ according to  FIG. 2  in that the last-mentioned switching devices not only relay the system statement, but the entire system message of a selected dialog expert, to main switching device  100 . To this end, main switching device  100  has a detector and decision device  104 , which, functioning in response to the system messages coming from switching devices  40 ′,  40 ″ and  40 ′″, selects an optimal system message and routes the system statement contained therein to the corresponding terminal device  10  or  20 . 
     FIG. 3  shows another exemplary embodiment of a dialog system, in which terminal devices  10  and  20  are connected, in turn, via corresponding user interfaces  12  and  22 , respectively, to a subscriber exchange  30 . In addition, the dialog system has a cascade connection of, for example, three dialog experts  130 ,  140 , and  150 , which are able to carry on a dialog with terminal devices  10  and  20 . Each dialog expert  130 ,  140  and  150  has a receiving and evaluation device  135 ,  145  and  155 , respectively, for receiving and evaluating a user statement generated by a terminal device. Moreover, each dialog expert  130 ,  140  and  150  includes a device  136 ,  146  and  156 , respectively, for generating a suitable system message as a function of the evaluated user statement. A decision device  137 ,  147  and  157  is provided in each dialog expert  130 ,  140 , and  150 . Decision devices  137 ,  147 , and  157  may relay the user statement obtained from an end device to the following dialog expert when it is recognized that the dialog expert in question is not able to generate a suitable system statement in response to the received user statement. In addition, decision devices  137 ,  147  and  157  may be able to transmit a generated system statement to the particular terminal device. It is assumed in the present example that terminal device  10  has been connected via exchange  30  to dialog expert  130 . It is also assumed that dialog expert  130  is not able to generate any suitable system statement in response to the user statement coming from terminal device  10 , so that the user statement is relayed to dialog expert  140 . Since dialog expert  140  is able to generate an appropriate system statement, a connection is established at this point between terminal device  10  and dialog expert  140 , and the generated system statement is transmitted to terminal device  10 . 
   It is also noted that all switching devices, sub-switching devices, dialog devices, and sub-dialog devices may be designed for the parallel, i.e., simultaneous handling of dialogs with a plurality of users. 
   With the aid of the proposed dialog systems, it may be possible to insert chat-oriented passages within predominately goal-directed dialog sessions, to prevent a dialog from being broken off or ending in a dialog loop when a goal-directed dialog expert may no longer be able to meaningfully respond to a user statement. User statements which lie outside of the modeled domain of a goal-directed dialog expert, may then be handled in the “chatty style”, with the aid of a so-called chat bot. Thus, the possibility is opened up of going beyond the existing technological boundaries of the individual dialog experts in a user-friendly way. Overall, therefore, the performance of the proposed dialog systems allows for the ability to handle deviations in user objectives, and to more successful and user-friendlier dialogs.