levelCache = new LinkedHashMap<Element, Integer>();
for (EObject child : getAccessLayer().getDirectChildren(getGss())) {
if (child instanceof Relation)
{
Relation relation = (Relation) child;
Element target = relation.getTarget();
Element source = relation.getSource();
String weight = null;
if (relation instanceof Offset) {
weight = getAccessLayer().getAttributeValue(relation, "value");
} else if (relation instanceof Impact) {