There are several typical cube computation methods, such as Multi Way [ZDN97], BUC [BR99], and Star-Cubing [XHLW03]. Briefly describe these three methods (i.e., use one or two lines to outline the key points), and compare their feasibility and performance under the following conditions:
(a) Computing a dense full cube of low dimensionality (e.g., less than eight dimensions).
(b) Computing an iceberg cube of around 10 dimensions with a highly skewed data distribution.
(c) Computing a sparse iceberg cube of high dimensionality (e.g., over 100 dimensions).