A modal converter assembly for healing tissue, the modal converter assembly comprises a transducer and a body. The process involves subjecting the feed material to an extractive distillation operation using an aromatic selective solvent in combination with a co-solvent. Each coil has forward extending arms including an angled portion and forward vertically coincident portions. A classifier generation unit substitutes feature quantities into weak classifiers constituting the transfer classifier, calculates error rates of the weak classifiers on the basis of classification results of the weak classifiers and a weight of the learning image, and iterates a process of selecting a weak classifier of which the error rate is minimized a plurality of times. Accordingly, using the humidification system of the invention, it is possible to provide the same level of humidification performance as the existing humidification system, manufacture the humidification system at low cost, and solve various problems such as a flooding phenomenon of a fuel cell stack and an increase in load on an air blower.