The invention relates to an apparatus and method for estimating the distance between a transmitter and a receiver. Stripe shape or rectangular shape unevenness or opening is formed. To dissolve the metal compound, a solvent having a boiling point under ordinary pressure of about 100 C. The algae are removed and processed, and the bags are cleaned and reused. As a result, even the operator or the customer not fully equipped with the knowledge of the product can obtain a sufficient retrieval result. One prioritization method may include receiving attributes of incidents and assets in the system, generating cumulative loss forecasts for the incidents, and prioritizing the responses to the incidents based on the cumulative loss forecasts for the incidents.