java - Triple extracción de una sesión

nlp rdf

Question

Tengo este texto analizado en este formato, lo obtuve usando Standford nlp.

   (ROOT
  (S
    (NP (DT A) (NN passenger) (NN plane))
    (VP (VBZ has)
      (VP (VBD crashed)
        (ADVP (RB shortly))
        (PP (IN after)
          (NP
            (NP (NN take-off))
            (PP (IN from)
              (NP (NNP Kyrgyzstan) (`` `) (NNP scapital) (, ,) (NNP Bishkek)))))
        (, ,)
        (VP (VBG killing)
          (NP
            (NP (DT a) (JJ large) (NN number))
            (PP (IN of)
              (NP
                (NP (DT those))
                (PP (IN on)
                  (NP (NN board)))))))))
    (. .)))

det(plane-3, A-1)
nn(plane-3, passenger-2)
nsubj(crashed-5, plane-3)
aux(crashed-5, has-4)
root(ROOT-0, crashed-5)
advmod(crashed-5, shortly-6)
prep_after(crashed-5, take-off-8)
nn(Bishkek-14, Kyrgyzstan-10)
nn(Bishkek-14, scapital-12)
prep_from(take-off-8, Bishkek-14)
dep(crashed-5, killing-16)
det(number-19, a-17)
amod(number-19, large-18)
dobj(killing-16, number-19)
prep_of(number-19, those-21)
prep_on(those-21, board-23) 

Estoy intentando construir un gráfico RDF y necesito una herramienta o una biblioteca para extraer el triplete (sujeto, objeto, predicado) de él.