<!ELEMENT trial (input)+> <!ELEMENT trial (input)+> <!ATTLIST trial id ID #REQUIRED> <!ELEMENT input (param)*> <!ATTLIST input type CDATA #REQUIRED> <!ELEMENT population (param)*> <!ATTLIST population id ID #REQUIRED> <!ATTLIST population type CDATA #REQUIRED> <!ELEMENT range EMPTY> <!ATTLIST range name CDATA #REQUIRED> <!ATTLIST range start CDATA #REQUIRED> <!ATTLIST range end CDATA #REQUIRED> <!ATTLIST range step CDATA "1"> <!ELEMENT param (#PCDATA | range)> <!ATTLIST param name CDATA #REQUIRED> <!ATTLIST param sigma CDATA "0"> <!ELEMENT connection EMPTY> <!ATTLIST connection from IDREF #REQUIRED> <!ATTLIST connection to IDREF #REQUIRED> <!ATTLIST connection weight CDATA #REQUIRED> <!ATTLIST connection sigma CDATA "0"> <!ATTLIST connection density CDATA "1"> <!ATTLIST connection direction CDATA "oneway">