<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSPY v2004 rel. 4 U (http://www.xmlspy.com) by Xiaotao Wu (Columbia University Computer Science Dept) -->
<xs:schema targetNamespace="xml:N3" xmlns="xml:N3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:N1="xml:N1" elementFormDefault="qualified" attributeFormDefault="unqualified">
  <xs:import namespace="xml:N1" schemaLocation="s1.xsd"/>
  <xs:complexType name="AcceptAction">
    <xs:complexContent>
      <xs:extension base="N1:ActionType">
        <xs:attribute name="media" type="xs:string" use="optional"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
  <xs:element name="accept" type="AcceptAction" substitutionGroup="N1:action"/>
</xs:schema>