golf contest analogy -------------------- Suppose there is a contest involving two rounds of golf with 10 men and 10 women. At the end, the best 3 total scores overall are declared winners. After one round, the best 3 scores, looking at the men and women separately, are: Round 1 M Viterbi 40 Kalman 50 Kevin 60 F Jill 40 Jane 45 Joan 50 Obviously, to determine the best 3 scores after two rounds, we can not just keep the best 3 scores after the first round and throw everyone else out. It may be that Shannon, who came in 4th in the first round in the mens group, and isn't listed above, performs extra well in round 2 and comes out the overall winner. After two rounds, the best 3 total scores for the men and women are shown in the "Round 1 + Round 2" column: Round 1 Round 1 + Round 2 M Viterbi 40 M Kevin 100 Kalman 50 Kalman 110 Kevin 60 Shannon 115 F Jill 40 F Jill 105 Jane 41 Jane 106 Joan 42 Joan 107 The three overall winners are: Kevin, Jill, and Jane. Comparing the total scores at the end with the scores from round 1, Kevin must have scored 40 in round 2, and Kalman must have scored 60. Viterbi, while in the lead after round 1, messed up in round 2 and came out 4th or lower. Shannon pulled up from behind and made it to third place in the mens group. In this example, each of the men listed had different scores in round 2. But each of the 3-best women had the same score of 65. The results going from round 1 to the end for the men are similar to the effects of using a Kalman cost function; each player (i.e. kalman filter) at each time unit (i.e. round 1 or round 2) is unique and has a performance that depends on their history (i.e. skill for the golf players; previous track data used in the evolution for the kalman filters). The results going from round 1 to the end for the women is similar to the standard viterbi cost function, which depends only on the state transition involved (i.e. cost going from state i to state k is only a function of i and k, and is the same for all golf players). Thus, regardless of their ranking after the initialization of round 1, all of the women get the same incremental cost (65 in this case) going from round 1 to round 2. So the best 3 women after round 1 remain the same after round 2. When applied to sports problems, the kalman filter cost function makes more sense than the standard viterbi cost function. The separation of scores into male and female groups in this example was done just to make some analogy to states in a viterbi trellis. So it's like there are two states, M and F, at each time unit. In this example, transitions between states M and F are not shown, and are a subject for further genetic research.