Methods and apparatus for automatic call routing including disambiguating routing decisions

• US 6,269,153 B1
• Filed: 07/29/1998
• Issued: 07/31/2001
• Est. Priority Date: 07/29/1998
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Chu-Carroll, Jennifer, Carpenter, Robert Lee
• Primary Examiner(s): SMITH, CREIGHTON H
• Application Number:
  US09/124,301
• Time in Patent Office: 1,098 Days
• Field of Search: 379/88.01, 379/88.02, 704/9, 382/159
• US Class Current: 379/88.02
• CPC Class Codes: H04M 1/645 with speech synthesis

Abstract

An automatic call routing system for directing a call to a desired destination. The routing system poses questions to a caller and uses the caller'"'"'s responses create a query which is used to direct the call to a destination associated with one of a plurality of documents created during a training phase. The documents are created by receiving calls, collecting caller contributions to each call, directing each call to a destination by a human operator, and storing and processing the caller contributions to each call directed to a particular destination. If a caller'"'"'s responses do not permit a call to be unambiguously routed to a destination, the routing system poses clarifying questions and receives caller responses. The caller responses are used to create a refined query for use in a subsequent attempt to route the call.

Claims

1. A call routing system for routing a call to a desired destination, comprising:

a caller interface for conveying information to a caller and receiving caller information from the caller for use in routing of a call;

a routing module for routing a call to a desired destination based on caller information received by the caller interface, the routing module being operative to formulate a query based on terms contained within the caller information, the routing module being further operative to determine a match between the query and one of a plurality of documents, each of the plurality of documents being associated with a destination, the routing module being operative to route the call to the destination associated with the document matching the query, the routing module being further operative to detect ambiguity in the match between the query and the one of the plurality of documents;

a disambiguation module for disambiguating an ambiguous match between the query and one of the plurality of documents, the disambiguation module being operative to create one or more disambiguating questions to be provided to the caller through the caller interface, the disambiguation module being further operative to receive an answer to the disambiguating questions from the caller interface, the disambiguation module being operative to add information from the answer to the disambiguating questions to the query to produce a refined query, the disambiguation module being further operative to return the refined query to the routing module for use by the routing module in routing the call; and

a training system for creating the plurality of documents, the training system being operative to receive a plurality of calls and store caller contributions to each call, each call being routed to a destination by a human operator, the training system being operative to create the plurality of documents by storing in each document associated with each of the destinations all terms of each call routed to the destination.

2. The call routing system of claim 1 wherein the training system is operative to create a training corpus by receiving a plurality of calls, routing each call to a destination via a human operator, and saving the text of the caller'"'"'s contribution of each call in a training document associated with the destination to which the call is routed.

3. The call routing system of claim 2 wherein the training system is further operative to filter each training document through a morphological processor to extract a root form of each word in the training document.

4. The call routing system of claim 3 wherein each of the root forms is filtered through an ignore list and a stop list, each root form appearing on the ignore list being removed, each root form on the stop list being replaced by a stop.

5. The call routing system of claim 4 wherein the training system is further operative to convert a result of filtering each training document to a routing document for use by the routing module.

6. The call routing system of claim 5 wherein the training system is further operative to create a term-document frequency matrix including a plurality of elements, each element of the term-frequency matrix representing a frequency of appearance of a term in a document.

7. The call routing system of claim 6 wherein the training system is further operative to perform weighting on the term-document frequency matrix to create a weighted matrix.

8. The call routing system of claim 7 wherein the training system is further operative to perform normalization on the weighted matrix to create a normalized matrix.

9. The call routing system of claim 8 wherein the normalized matrix is used as a scoring matrix containing scoring information for use in associating a query with a document based on matching terms contained in the query with term information contained in the matrix.

10. The call routing system of claim 9 wherein the routing module includes a term extractor which extracts terms from the query.

11. The call routing system of claim 10 wherein the term extractor assembles the terms extracted from the query into a pseudo-document vector.

12. The call routing system of claim 11 wherein the routing module evaluates the pseudo-document vector is against the scoring matrix to develop a query-document score for each document.

13. The call routing system of claim 12 wherein the routing module compares the query document score for each document against a threshold.

14. The call routing system of claim 13 wherein the routing module routes the call to a destination if one document has a query-document score meeting the threshold, wherein the routing module passes the call for alternative routing if no document has a query-document score meeting the threshold, and wherein the routing module passes the call to the disambiguation module if more than one document has a score meeting the threshold.

15. The call routing system of claim 14 wherein the disambiguation module receives from the routing module the pseudo-document vector and identities of the documents exceeding the threshold.

16. The call routing system of claim 15 wherein the disambiguation module includes a question generator to create disambiguating questions for disambiguating documents.

17. The call routing system of claim 16 wherein the question generator includes a term selector to select close, relevant, and disambiguating terms for creation of disambiguating questions, each selected term being assigned a score, the question generator being operative to use the selected terms in the disambiguating questions.

18. The call routing system of claim 17 wherein the question generator is operative to examine the selected terms to determine if they form a common headword and, if the selected terms form a common headword, to use the common term in forming a question for distinguishing between the terms by asking the customer to provide further information specifying the term that is meant, the question being relayed to the caller and the caller'"'"'s response being received, the caller'"'"'s response being passed to the routing module for formation of a new query including the caller'"'"'s response added to the original query.

19. The call routing system of claim 18 wherein the question generator is further operative, if the selected terms do not form a common headword:

(a) to form a yes-no question using the selected term having the highest score and receive a response from the caller;

(b) to evaluate the response to determine if the response is affirmative or negative;

(c) if the response is negative, to form a question using the next-highest-scoring selected term, relay the question to the caller, receive the caller'"'"'s response, and return to (b) if the number of attempts does not exceed a predetermined number;

(d) if the response is affirmative, to route the call to the destination indicated by the selected term.

20. A method of routing calls to one of a plurality of destinations comprising the steps of:

performing a training phase to create a plurality of documents, each document being associated with a destination, and document information for use in associating a document with a query, the document information including a scoring matrix containing information usable to associate the query with one of the plurality of documents, the training phase comprising the steps of;

creating a training corpus comprising a plurality of training documents;

performing morphological processing to convert each training document to a morphologically processed document;

filtering each morphologically processed document against an ignore list and a stop list to create a filtered training document;

converting each filtered training document to a routing document;

creating a term-document frequency matrix using the information in the routing documents;

weighting the term-document frequency matrix to create a weighted matrix;

copying the weighted matrix to a scoring matrix;

resolving the scoring matrix to produce an equivalent matrix set;

storing the equivalent matrix set in the scoring matrix; and

creating scoring data from the equivalent matrix set;

receiving a call and exchanging information with a caller, the step of receiving a call including receiving responses from the caller;

extracting terms from the responses from the caller to create the query;

using the query to create a pseudo-document vector;

computing a query-document score for each document using the pseudo-document vector and the scoring matrix;

comparing the query-document score for each document against a threshold;

if no document meets the threshold, routing the call to an alternative routing system;

if the score for one document meets the threshold, routing the call to the destination associated with the one document; and

if the score for more than one document meets the threshold, performing disambiguation between the documents.

21. A call routing system for routing a call to a desired destination, comprising:

a caller interface for conveying information to a caller and receiving caller information from the caller for use in routing of a call;

a routing module for routing a call to a desired destination based on caller information received by the caller interface, the routing module being operative to formulate a query based on terms contained within the caller information, the routing module being further operative to determine a match between the query and one of a plurality of documents, each of the plurality of documents being associated with a destination, the routing module being operative to route the call to the destination associated with the document matching the query, the routing module being further operative to detect ambiguity in the match between the query and the one of the plurality of documents;

a disambiguation module for disambiguating an ambiguous match between the query and one of the plurality of documents, the disambiguation module being operative to create one or more disambiguating questions to be provided to the caller through the caller interface, the disambiguation module being further operative to receive an answer to the disambiguating questions from the caller interface, the disambiguation module being operative to add information from the answer to the disambiguating questions to the query to produce a refined query, the disambiguation module being further operative to return the refined query to the routing module for use by the routing module in routing the call.

22. A method of routing calls to one of a plurality of destinations comprising the steps of:

performing a training phase to create a plurality of documents, each document being associated with a destination, and document information for use in associating a document with a query, the document information including a scoring matrix containing information usable to associate the query with one of the plurality of documents;

receiving a call and exchanging information with a caller, the step of receiving a call including receiving responses from the caller;

extracting terms from the responses from the caller to create the query;

using the query to create a pseudo-document vector;

computing a query-document score for each document using the pseudo-document vector and the scoring matrix;

comparing the query-document score for each document against a threshold;

if no document meets the threshold, routing the call to an alternative routing system;

if the score for one document meets the threshold, routing the call to the destination associated with the one document; and

if the score for more than one document meets the threshold, performing disambiguation between the documents, disambiguation being performed by;

creating one or more disambiguating questions to be provided to the caller;

receiving an answer to the disambiguating questions from the caller;

adding information from the answer to the disambiguating questions to the query to produce a refined query; and

using the refined query to route the call.