Table 7: Comparison of PACO with three ACO-based algorithms.

Prob. BKS IACS [12] SS_ACO [13] EACO [15] PACO C1 50 5 524.61 524.61 */3 524.61 */55.23 524.61 */— 524.61 */0.79 C2 75 10 835.26 836.18/26 835.26 */70.43 835.26 */— 835.26 */163.44 C3 100 8 826.14 835.6/101 830.14/120.25 826.14 */— 829.92/183.08 C4 150 12 1028.42 1038.22/617 1038.20/250.76 1041.83/— 1040.23/547.88 C5 199 17 1291.45 1327.07/3080 1307.18/707.80 1338.48/— 1348.73/1455.64 C6 50 6 555.43 555.43 */5 559.12/65.17 555.43 */— 555.43 */7.72 C7 75 11 909.68 909.68 */41 912.68/90.42 909.68 */— 909.68 */66.68 C8 100 9 865.94 865.94 */115 869.34/210.46 865.94 */— 868.61/146.5 C9 150 14 1162.55 1173.76/853 1179.4/520.52 1168.81/— 1171.94/614.53 C10 199 18 1395.85 1413.83/4223 1410.26/1012.23 1413.69/— 1454.81/1114.21 C11 120 7 1042.11 1042.11 */204 1044.12/232.46 1045.5/— 1042.11 */95.33 C12 100 10 819.56 832.67/88 824.31/156.47 819.56 */— 819.56 */122.87 C13 120 11 1541.14 1547.07/428 1556.52/467.24 1554.93/— 1562.64/156.32 C14 100 11 866.37 866.37 */125 870.26/368.72 866.37 */— 866.37 */32.75

Notes: = f(best solution)/shortest CPU Time (s), BKS is the best-known solution provided by published papers, —denotes that the data is not available, IACS used Intel Pentium III CPU 1000 MHz with 128 MB RAM, SS_ACO used IBM computer CPU 1600 MHz with 512 MB RAM, and EACO used Pentium IV CPU 3.0 GHz.