The ABL system used infrared sensors for initial missile detection. Regular monitoring allows for early detection and treatment. Absolute threshold is measured by using a method called signal detection. Hearing (or "audition") is the ability to perceive sound by detecting vibrations (i.e., "sonic" detection). Automatic duplicate address detection algorithms prevent assignment errors. There are two methods for simultaneous detection and quantification. Quantifying gene expression by traditional DNA detection methods is unreliable. Methods for collision detection are media dependent. A variety of methods for leak detection exist. Testing blood for hCG results in the earliest detection of pregnancy. There are various methods of outlier detection. The OES-52 provides greater range of target detection and recognition. This problem has applications in error detection and correction. There are two main classes of detection methods. It uses a convolutional code for error detection and correction.