The NuGram approach to dynamic grammars

Introduction
What is a dynamic grammar?
A grammar whose content is not known in advance
Content comes from an external source
Database
Excel sheet
Web service
Data collected during the call
Etc.
Copyright © 2010 Nu Echo Inc.

Introduction
Why dynamic grammars?
Grammar content is only known at run-time
To constrain grammars in order to improve recognition accuracy
To solve maintenance problems
More details on our blog:
http://blog.nuecho.com/2008/10/06/use-cases-for-dynamic-grammars/
http://blog.nuecho.com/2008/10/09/use-cases-for-dynamic-grammars-part-2/

Use Cases
On-the-fly generation
Content comes from call-specific data
Examples
Identity validation
Address capture
Voice dialing
Personalized bill payee list
Personalized menu options
One-step correction

Use Cases
Offline generation (triggered)‏
Results from an external event
Examples:
Auto-attendant
Movie listings

Use Cases
Offline generation (scheduled)‏
Grammar generation is part of a scheduled maintenance process
Examples
Phone numbers (area code may be added)‏
Postal/Zip codes
Stock quotes, mutual funds
Bill payee list management

Use Cases
Offline generation (build time)‏
For grammars based on company-specific data
Usually requires scheduled maintenance process
Examples
Branch names and addresses
Stock quotes, mutual funds
Bill payee list management

The NuGram Approach
Seamless evolution

The Generation Process
ABNF
Grammar
Template
Grammar
GSL
Instantiation
context
GrXML

Start with an ABNF grammar
#ABNF 1.0 ISO-8859-1;
languageen-US;
root$name;
public$name=
[$pre_filler] $employeeName[$post_filler];
$employeeName=
[dominique] boucher;

Add dynamic directives
#ABNF 1.0 ISO-8859-1;
language@string callerLanguage;
root$name;
public$name=
[$pre_filler] $employeeName[$post_filler];
$employeeName =
[@word employee.firstname] @word employee.lastname;

Complex objects and control-flow
$employeeName =
@alt
@for(entry : entries)‏
@if(entry.isDepartment)‏
@word entry.name
@else
([@word entry.firstname]
@word entry.lastname
@end
@end
@end
;

NuGram Server
Runtime infrastructure to deploy dynamic grammars
Java Servlettechnology
Can run in parallel/be packaged with your application
Outputs grammars in ABNF, GrXML, GSL
Fine-grained control of caching strategy
Using configuration or Java API
Two sets of APIs
JSP-like API
REST API

NuGram Server
JSP-like API
Instantiation + Generation at once
Java code creates the instantiation context
Can access databases, webservices
Can access application data
Can access parameters passed on the request URL
Build the URL, let the ASR fetch the generated grammar
http://localhost:8800/nugram-servlet/grammars/address.grxml?code=h3b1a7
Output Format
HTTP Parameters

NuGram Server
Java Context Initializers for full control
publicclassCanadianAddressContextInitializerimplementsContextInitializer{public Map getContext(Map httpParameters,GrammarFragmentFactory factory,CacheControl control) {Map context = new HashMap();// 1. Extract the HTTP parameterString[] postalCode = httpParameters.get(“code”); // 2. Look in the postal code databasePostalCodeRecord[] records = findRecords(postalCode);// 3. Populate the instantiation contextcontext.add(“records”, records);context.add(“helper”, new AddressHelper(factory));return context; }

NuGram Server
JSP-like API – Tight integration with Java
#ABNF 1.0 UTF-8;languagefr-CA;mode voice;root$address;public$address = @alt@for (record : records)@fragmenthelper.civicNumber(record)@wordrecord.streetName [@wordrecord.streetType]@end@end;
Methods can be called on Java objects and produce grammar fragments (using a provided API)
Supports bean properties - the real method is “getStreetName()”

NuGram Server
REST API
HTTP-based
Contexts sent to server as JSON objects
Instantiation decoupled from generation for more effective use of resources
Application POSTs request to instantiate the grammar
NuGram Server replies with an URL
Application passes the URL to the ASR
ASR fetches grammar using the given URL

Benefits
No distinction between dynamic grammars and static grammars
Supported by a complete development environment – NuGram IDE
Editor, debugging tools, coverage tool, sentence generation tool, etc. – they all work with dynamic grammars
Easy to use, easy to deploy
Pure Java servlet technology
A proven technology
Deployed in many large IVR applications

Try it, it’s free!
NuGram Hosted Server (REST API only): http://www.grammarserver.com
Ideal for cloud-based telephony applications(Tropo, Voxeo Evolution, Teleku, etc.)
A bunch of client APIs: http://github.com/nuecho/nugramserver-clients
And of course the IDE: http://nugram.nuecho.com/

The NuGram approach to dynamic grammars

by Nu Echo Inc. on May 07, 2010

Accessibility

Categories

Tags

Upload Details

Usage Rights

2 Embeds 79

Statistics

The NuGram approach to dynamic grammars — Presentation Transcript

http://blog.nuecho.com	69
http://www.slideshare.net	10