A method for producing an unsaturated nitrile by a propane ammoxidation reaction, the method including:a step of measuring at least one physical property value selected from the group consisting of the normalized UV value and the reduction ratio of a catalyst contained in a reactor, anda step of maintaining or changing a reaction condition based on the measured physical property value. The second portion has an elastane content greater than that of the first portion. Windows are sequentially processed in pairs to derive the code words for the input that has been trellis coded. The IO buffer also includes a pull-up transistor bias circuit to provide the voltage to the gate and the body of the pull-up transistor. In some embodiments, the end-user device determines the importance of a chunk based on observations of the behavior of the device’s user.