A detailed explanation of the coda naming scheme used is described in van der Schaar and André (2006). Since codas are analyzed by the rhythm of the inter-pulse intervals a naming protocol has been adopted that emphasizes this rhythm. Usually the name of a coda cluster type is based on counting the pulses, grouping pulse intervals that are 'closer' together without defining closer. This not only makes it difficult to compare coda types between different research projects but also discards important information about the actual pulse intervals. For example the following image shows two 5-pulse codas, when found in different studies both would be named 1+2+2 while they have different rhythms. If they were found in the same study they might be named 1+2++2 and 1+2+2 to indicate a longer interval, still giving little information about the pulse intervals and how the coda groups can be compared.

In order to preserve the interval information and eliminate objectivity this program follows a fixed naming protocol that is based on the pulse intervals. A perfectly regular n-pulse coda would have pulse interval lengths of 1/(n-1). Dividing the area between 0 and 1/(n-1) in 3 equal parts, a very short (VS) pulse interval is defined as less than 1/3(n-1). Then an interval is called short (S) or regular (R) if an interval is shorter than 2 or 4 times the very short pulse interval. The remaining area between regular intervals and 1 is divided in two for long (L) and very long (VL) pulse intervals. This partitioning is shown in the figure below.

Using this naming scheme the two codas above would be named R+S+L+S and L+VS+L+VS. Additionally consecutive pulse intervals can be combined when they fall in the same label interval, but they should also be combined when they have similar lengths. The analyzer combines the intervals when the interval means are within two standard deviations, ie. if |m₁ - m₂| < s₁ + s₂, where m_1,2 are the sample means and s_1,2 the sample standard deviations.

Citation :
van der Schaar, M. and M. André (2006), An Alternative Sperm Whale Coda Naming Protocol, under submission. Available at request.

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