Spoken Dialogue Agent Architecture for Web Service Mediator

Transcription

1 Spoken Dialogue Agent Architecture for Web Service Mediator Masahiro Araki Kyoto Institute of Technology Matsugasaki Sakyo-ku Kyoto Japan Tel: Fax: Abstract In this paper, we propose a spoken dialogue agent architecture which can control virtual electronic devices via Web services. Each device is assumed to have Web service interface which can register its control functions and command ontology to the server. The dialogue agent can acquire dialogue knowledge from the server and dynamically change its dialogue transition rule according to the status of the device. We explain an experimental architecture of such a Web service mediator agent using VoiceXML interpreter and Servelet environment. 1. Introduction Recently, Web service is expected to be a standard for application program interconnections not only for enterprise solutions but also small scale collaborations such as a home electronics network. In home electronics network, each devices, such as video recorder, intelligent refrigerator, air conditioner, are connected to a home network and collaborate with each other. Such devices will have many functions but will become more difficult to use than today's home electronic devices. An intelligent agent is one solution to such interface problem. The agent is expected to have an ability of natural language communication with human and to have mediator function to the complex home electronic devices. However, it is unrealistic for each devices having different dialogue agent who has different type of dialogue pattern. It is desirable for users to have one intelligent agent who can control all the networked home electronic devices intelligently and collaboratively following the user's natural language command. In order to realize such an intelligent dialogue agent, we need a dynamic construction method of dialogue knowledge according to the changing environment, such as installing a new device and temporary uninstalling an out-of-order device. In this paper, we propose a spoken dialogue agent architecture which can control virtual electronic devices via Web services. Each device is assumed to have Web service interface which can register its control functions and command ontology to the server. The dialogue agent can acquire dialogue knowledge from the server and dynamically change its dialogue transition rule according to the status of the device. We explain an experimental architecture of such a Web service mediator agent using VoiceXML interpreter and Servelet (server side application) environment. This paper is constructed as follows. Section 2 explains a virtual setting of home electronics network environment and outlines a behavior of the dialogue agent. Section 3 describes a mechanism of services and dialogue knowledge registration by Web service. Section 4 shows how the agent acquires and reconstructs dialogue knowledge. Section 5 describes our future works. 2. Dialogue agent in Web service environment This section describes a virtual setting of

2 home electronics network environment and outlines a behavior of the dialogue agent. We assume all the home electronic devices which are controlled by the dialogue agent have an ability of remote control interface by Web service. In other words, each device can be regarded as a Web service provider which opens a controllable interface for changing internal state via SOAP (Simple Object Access Protocol) [1] message exchange. SOAP protocol functions as an envelope for XML message between networked devices. SOAP guarantees interconnections between heterogeneous networked devices. In addition, an UDDI (Universal Description, Discovery and Integration) [2] server at the home network provides a collaboration (discovery of services and exchange of WSDL (Web Services Description Languages [3]) information for Web services) between networked devices. Service providers, such as video recorder or intelligent microwave oven, register their functions and interface descriptions in order to call such functions as if a remote procedure call. On the other hand, service requester, i.e. a dialogue agent who is a representative of user, searches the service at the UDDI server. Basic structure of Web service is shown in Figure 1. Figure 1. Basic Web service architecture. We apply such general, large scale network services to small scale home network as illustrated in Figure 2. Figure 2. Web service for home network. Historically, as world wide Internet technologies matured, they were successfully applied to small scale Intranet because of their reliability and performance. For example, HTTP, which originally developed for world wide document exchange, is used for Intranet applications which use Web server as an intranet application server and Web browser as a client. Similarly, Web service, which is expected to be a standard method for enterprise network services, can be applied smaller network. Its messaging protocol (SOAP) and interface protocol (WSDL) provide basic procedure derived from distributed object model. Therefore, it is easy to design small scale networked collaboration model using Web service architecture. It is suitable for standard protocol in home electronics network. The main theme of this paper is to propose architecture of dialogue agent which is located at such Web service network. The agent can interact with user by spoken language in order to control networked devices and autonomously acquire dialogue knowledge about other devices connected to the network. 3. Dialogue knowledge registration This section describes a method of (1)

3 registering new services from networked devices, and (2) registering corresponding dialogue knowledge. 3.1 Registering new services to the home server When a new networked device is installed to the home network, it registers its services to the home server in order to open the services to other networked devices. In addition, our proposed network architecture enables the new device to provide dialogue interface knowledge to the service. For example, when a new video recorder is installed to the network, it opens the services, such as reservation of recording, via its remote controller, remote access controller (e.g. telephone), and other devices. The sample SOAP message requesting program recording reservation is shown in Figure 3. <SOAP-ENV:Envelope> <SOAP-ENV:Body> <vox:reserveprogram xmlns:vox=" <StartTime> T15:00:00 </StartTime> <EndTime> T16:00:00 </EndTime> <Channel> VHF8 </Channel> <Mode> SP </Mode> </ vox:reserveprogram> </SOAP-ENV:Body> </SOAP-ENV:Envelope> Figure 3. SOAP message for TV program recording reservation. 3.2 Registering dialogue interface knowledge We assume each device provides dialogue interface knowledge for each service. We assume such dialogue interface is realized by VoiceXML [4], which is a standard dialogue pattern description language for interactive voice response systems. The dialogue interface corresponding TV program recording reservation (Figure 3) is shown in Figure 4. <SOAP-ENV:Envelope> <SOAP-ENV:Body> <vox:reserveprogramvxml xmlns:vox=" <vxml version="1.0"> <form> <field name="starttime"> <grammar src="datetime.gram"/> <prompt> When the program starts?</prompt> </field> <field name="endtime"> <grammar src="datetime.gram"/> <prompt> When the program ends? </prompt> </field> <field name="channel"> <grammar src="tvchannel.gram"/> <prompt> Which channel? </prompt> </field>... <submit next="vcr.jsp"> </vxml> </ vox:reserveprogramvxml> </SOAP-ENV:Body> </SOAP-ENV:Envelope> Figure 4. Dialogue interface for TV program recording reservation in VoiceXML. The dialogue knowledge is embedded in the body of the SOAP message. In this example, represented dialogue knowledge is a dialogue pattern of system initiative dialogue which gathers the necessary information (start time, end time, channel number and recording mode) in order to record a TV program. 4. Acquisition and reconstruction of dialogue knowledge Following the dialogue knowledge registration method explained in section 3, our proposed agent architecture is shown in Figure 5.

4 Figure 5. Dialogue agent architecture. 4.1 Acquisition of dialogue knowledge When a new device is installed to the network, it resisters the services and corresponding dialogue patterns to the home server. The dialogue agent regularly searches new devices and services. When the agent finds out a new device, it reconstructs the top level dialogue menu in the first place. Choice element and the link information to the service selection dialogue are added to the original top menu dialogue. The prompt sentence and grammar entry are automatically changed by the VoiceXML menu dialogue capabilities. The next service selection level dialogue is automatically constructed by the service information acquired from the UDDI server. For example, a TV recorder is registered at the home server, the top menu VoiceXML file of the agent is reconstructed as shown in Figure 6. In addition, new services are listed up under the TV recorder menu (Figure 7). An example of dialogue is shown in Figure 8. <vxml version="1.0"> <menu> <prompt> Which equipment do you use? <enumerate/> </prompt> <choice next="telephone.vxml"> telephone <choice next="tv.vxml"> television <choice next="tvrecorder.vxml"> TV recorder </menu> </vxml> Figure 6. Top level menu dialogue of the agent (added part is shown by Italic, bold). <vxml version="1.0"> <menu> <prompt> Which service do you use, <enumerate/> </prompt> <choice next="reserve.vxml"> recording reservation <choice next="cancel.vxml"> cancel reservation <choice next="play.vxml"> play </menu> </vxml> Figure 7. TvRecorder.vxml file.

5 System: This is home network agent. Which equipment do you use? User: TV recorder. S: Which service do you use, recording reservation, cancel reservation, play? U: Recording reservation. S: When the program starts? U: 15:00, today. S: When the program ends? U: 16:00. S: Which channel? U: 8. S: Which mode, SP or EP? U: SP. S: TV program May 10, 15:00 to 16:00, channel VHF 8, SP mode will be recorded. Is that O.K.? U: O.K. Figure 8. Example of TV recording reservation dialogue. This reconstruction is static because it does not matter the status of target devices. Next subsection explains dynamic reconstruction which can reflect the status of the devices. 4.2 Dynamic reconstruction of dialogue knowledge In Web service, some kinds of errors are captured as SOAP message level, i.e. SOAP fault. In home network, some devices might not be available because of a shortage of resources, e.g. run out of HDD for TV recorder. Such trouble information should be reported to the user as early stage of dialogue as possible, rather than after the user enters all the information for services. In this situation, dialogue component is dynamically reconstructed. When the agent receives SOAP fault message (Figure 9) from the device, the service selection level dialogue is replaced by error reporting dialogue. The content of <message> element of SOAP fault message is used for error reporting. <SOAP-ENV:Envelop> <SOAP-ENV:Body> <SOAP-ENV:Fault> <faultcode> SOAP-ENV:Server </faultcode> <faultstring> Server Error </faultstring> <detail> <message> Shortage of HDD capacity. </message> </detail> </SOAP-ENV:Fault> </SOAP-ENV:Body> </SOAP-ENV:Envelop> 5. Conclusion Figure 9. SOAP fault message. In this paper, we proposed a spoken dialogue agent architecture which can control virtual electronic devices via Web services. The dialogue agent can acquire dialogue knowledge from the server and dynamically change its dialogue transition rule according to the status of the device. We explained conceptual architecture such Web service mediator agent using VoiceXML interpreter and Servelet environment. Proposed architecture is preliminary version. We have several research plans on this architecture. 1. Reconstructing user's grammar at the top level menu selection. In this version, we use menu type dialogue for selecting controlled device. However, it is better for users to use direct command to each devices, such as, "I'd like to reserve TV recording." In order to deal with such type of spontaneous utterances, the system should use statistical language model. Therefore, the dialogue reconstruction can be regarded as a mixing procedure for several statistical language models.

6 2. Automatic generation of dialogue component from SOAP message or WSDL. We proposed dialogue pattern generation method from XML [5] or from XML scheme language [6]. Applying this framework, we can automatically generate VoiceXML part shown in Figure Learning user's behavior. Because dialogue pattern resides on the dialogue agent in our architecture, this pattern can be customized according to the past user's behavior. [6] M. Araki,Automatic Generation Method of Spoken Dialog Systems from XML Scheme Language (in Japanese), Information Technology letters, Vol.1, pp.97-98, Reference [1] Don Box, David Ehnebuske, Gopal Kakivaya, Andrew Layman, Noah Mendelsohn, Henrik Frystyk Nielsen, Satish Thatte, and Dave Winer: Simple Object Access Protocol (SOAP) 1.1, W3C Note, [2] Tom Bellwood, Luc Clement, David Ehnebuske, Andrew Hately, Maryann Hondo, Yin Leng Husband, Karsten Januszewski, Sam Lee, Barbara McKee, Joel Munter, Claus von Riegen: UDDI Version 3.0, UDDI Spec Technical Committee Specification, [3] Erik Christensen, Francisco Curbera, Greg Meredith, Sanjiva Weerawarana: Web Services Description Language (WSDL) 1.1 W3C Note, [4] Linda Boyer et. al.: Voice extensible markup language VoiceXML, [5] M. Araki, T. Ono, K. Ueda,T. Nishimoto, and Y. Niimi, An Automatic Dialogue System Generator from the Internet Information Contents,Proc, EUROSPEECH2001, pp , 2001.