The invention relates to a method of troubleshooting process issues using an Expert System. The plasma display panel has an electrode structure in which a second gap formed between electrode pairs in a discharge cell at a corner region of the panel is smaller than a gap formed between electrode pairs in a discharge cell at a more peripheral region of the panel. Parameter data may also be received for the identified algorithm. A functional unit therein is coupled to two or more of the registers and comprises a chain of functional unit segments that each comprise an AND gate and a 1-bit full adder receiving an output of the AND-gate. A corresponding apparatus and computer program product are also provided. A cavity may be formed in a back side of the impeller, opposite with at least one of the plurality of pitches.