var Person = {
  full_name: function() {
    return this.first_name + " " + this.last_name;
  }
}

function PersonFactory(first_name, last_name) {
    var person = Object.create(Person);
    person.first_name = first_name;
    person.last_name = last_name;
    return person;
}

var daniel = PersonFactory('Daniel', 'Wagener');
console.log(daniel.full_name()); //Daniel Wagener