Convertir json en nodes/links ?

Bonjour,
Je veux visualiser l'ontologie pizza.owl comme un "force-directed graph" en utilisant D3.js
J'ai converti pizza.owl en json en utilisant "OWL2VOWL.jar". Et j'ai obtenu le syntaxe suivant:

"instances" : 0
  }, {
    "id" : "class23",
    "label" : {
      "IRI-based" : "MeatyPizza",
      "pt" : "PizzaDeCarne",
      "en" : "MeatyPizza"
    },
    "iri" : "http://www.co-ode.org/ontologies/pizza/pizza.owl#MeatyPizza",
    "attributes" : [ "external", "equivalent" ],
    "annotations" : {
      "prefLabel" : [ {
        "identifier" : "prefLabel",
        "language" : "en",
        "value" : "Meaty Pizza",
        "type" : "label"
      } ],
      "definition" : [ {
        "identifier" : "definition",
        "language" : "en",
        "value" : "Any pizza that has at least one meat topping",
        "type" : "label"
      } ]
    },
    "instances" : 0,
    "intersection" : [ "class63", "class75" ]
  }, {
    "id" : "class99",
    "label" : {
      "IRI-based" : "RealItalianPizza",
      "pt" : "PizzaItalianaReal",
      "en" : "RealItalianPizza"
    },
    "iri" : "http://www.co-ode.org/ontologies/pizza/pizza.owl#RealItalianPizza",
    "attributes" : [ "external", "equivalent" ],
    "annotations" : {
      "prefLabel" : [ {
        "identifier" : "prefLabel",
        "language" : "en",
        "value" : "Real Italian Pizza",
        "type" : "label"
      } ],

Mais en fait D3.js force directed graph nécessite que les données json soient avec le format (nodes/links) comme dans l'exemple du lien ci dessous:
https://bl.ocks.org/jpurma/6dd2081cf25a5d2dfcdcab1a4868f237#graph.js

A partir de mon syntax, comment je peux obtenir le format suivant ?

{
"nodes": [
{"id": "Myriel", "group": 1},
{"id": "Napoleon", "group": 1},
{"id": "Mlle.Baptistine", "group": 1},
{"id": "Mme.Magloire", "group": 1},
{"id": "CountessdeLo", "group": 1},
{"id": "Geborand", "group": 1},
...],
"links": [
{"source": "Napoleon", "target": "Myriel", "value": 1},
{"source": "Mlle.Baptistine", "target": "Myriel", "value": 8},
{"source": "Mme.Magloire", "target": "Myriel", "value": 10},
{"source": "Mme.Magloire", "target": "Mlle.Baptistine", "value": 6},
{"source": "CountessdeLo", "target": "Myriel", "value": 1},
{"source": "Geborand", "target": "Myriel", "value": 1},
....]}