An optical waveguide module includes a wiring board, and a light-receiving element and optical waveguide substrate that are positioned on both sides of this wiring board. For each of at least particular ones of the plurality of documents, a score is assigned to that particular document, with respect to a topic, based at least in part on an incoherency characteristic associated with at least one document linking to that particular document. The capacitor to store a voltage based on the received AC power, and the transistor to remove a portion of the power stored in the capacitor based on the received AC power. A molten alloy is supplied alternately to the cooling roll 113a and the cooling roll 113b while rotating and water-cooling the cooling rolls 113a and 113b.