What is MTBF? Is it distinct from Life Cycle?

                                                                                                                
MTBF and Life Cycle are both indicators of reliability. KRECO uses MIL-HDBK-217F as the core of MTBF. An expected reliability is forecasted through accounting component's number (exclude fans).
The exact meaning of MTBF is after continuously using of power supply in a certain time, the probability of operating properly is 36.8%（e-1=0.368）. If power supply is continuously used at double the MTBF time, the probability of operating properly becomes 13.5%（e-2=0.135）.
Life Cycle is found through using the temperature rise of electrolytic capacitor to estimate the approximate life of power supply. For example, SP-750-12 MTBF=769.3K hours; electrolytic capacitor C108 Life Cycle=202.2K hours (Ta=45?C).