Large-Scale Storage/Retrieval Requests Sorting Algorithm for Multi-I/O Depots Automated Storage/Retrieval Systems
Table 5
Comparisons of unload times between NN and proposed method for large-scale problem.
N_r
Nearest neighbor
Assignment
Diff1
Diff2 (%)
T_NLa
CPU
T_NLb
CPU
N_SL
EMT
MinMT
15
458.2
0.0224
429.2
0.016
15
458.2
0.0224
29
6.33
15
382.0
0.0284
366.6
0.016
3
2
0
15.4
4.20
15
355.2
0.0262
339.4
0.062
3
1
1
15.8
4.66
15
513.6
0.0248
444.6
0.016
2
1
0
69
15.52
15
513.6
0.0268
382.2
0.016
2
1
0
131.4
34.38
15
451.8
0.0287
416.2
0.016
0
0
0
35.6
8.55
15
519.2
0.0291
480.4
0.015
2
1
0
38.8
8.08
15
487.8
0.0285
469.2
0.016
3
2
0
18.6
3.96
15
401.4
0.0279
386.2
0.015
3
1
1
15.2
3.94
15
550.6
0.0261
521.2
0.016
0
0
0
29.4
5.64
20
613.6
0.0268
561.4
0.016
3
2
0
52.2
9.30
20
612.6
0.0259
581.4
0.016
2
1
0
31.2
5.37
20
612.6
0.0268
569.4
0.016
2
1
0
43.2
7.59
20
726.8
0.0261
709.4
0.015
0
0
0
17.4
2.45
20
573.6
0.0223
551.2
0.016
3
2
0
22.4
4.06
20
599.6
0.0272
585.2
0.016
2
1
0
14.4
2.46
20
607.4
0.0249
576.4
0.015
0
0
0
31
5.38
20
636.2
0.0259
602.4
0.016
3
1
1
33.8
5.61
30
884.8
0.0351
865.4
0.016
2
1
0
19.4
2.24
30
1007.6
0.0335
944.0
0.031
2
1
0
63.6
6.74
30
950.8
0.0373
928.4
0.047
2
1
0
22.4
2.41
30
850.4
0.0395
842.8
0.031
3
2
0
7.6
0.90
30
810.8
0.0362
785.2
0.031
3
2
0
25.6
3.26
30
878.6
0.0332
840.6
0.031
2
1
0
38
4.52
30
911.0
0.0387
862.6
0.015
2
1
0
48.4
5.61
30
859.6
0.0462
832.6
0.031
2
1
0
27
3.24
50
1536.6
0.0442
1499.4
0.078
3
2
0
37.2
2.48
50
1610.8
0.0418
1561.8
0.094
3
2
0
49
3.14
50
1469.4
0.0424
1418.6
0.047
0
0
0
50.8
3.58
50
1470.4
0.0455
1447.0
0.063
2
1
0
23.4
1.62
50
1395.0
0.0448
1344.0
0.047
2
1
0
51
3.79
50
1373.8
0.0472
1322.0
0.063
2
1
0
51.8
3.92
50
1563.8
0.0475
1497.2
0.062
2
1
0
66.6
4.45
50
1695.2
0.0456
1670.2
0.078
2
1
0
25
1.50
50
1461.8
0.0429
1447.0
0.047
2
1
0
14.8
1.02
50
1268.0
0.0505
1221.6
0.047
2
1
0
46.4
3.80
80
2185.6
0.0611
2118.2
0.156
3
2
0
67.4
3.18
80
2386.8
0.0668
2359.8
0.171
3
1
1
27
1.14
80
2236.4
0.0634
2196.0
0.14
2
1
0
40.4
1.84
80
2281.6
0.0602
2244.6
0.125
0
0
0
37
1.65
80
2235.6
0.0636
2190.4
0.156
2
1
0
45.2
2.06
80
2367.2
0.0629
2310.4
0.156
2
1
0
56.8
2.46
80
2311.2
0.0695
2247.8
0.187
3
2
0
63.4
2.82
80
2389.2
0.0615
2359.8
0.187
3
2
0
29.4
1.25
80
2450.6
0.0658
2405.4
0.203
2
1
0
45.2
1.88
100
2949.6
0.0748
2891.6
0.328
3
2
0
58
2.01
100
3169.4
0.0758
3069.8
0.312
2
1
0
99.6
3.24
100
3081.0
0.0746
3028.8
0.234
2
1
0
52.2
1.72
100
2845.8
0.0837
2795.0
0.359
3
2
0
50.8
1.82
Note. Five-layer double row shelf with 15 I/O depots; N_r: number of S/R requests; T_NL: no-load travel time of stacker (sec); CPU: computation time (sec); N_SL: the number of subloops; EMT: the equivalent merging times of subloops; MinMT: the minimum cost merging times of subloops; Diff1 = T_NLa − T_NLb; Diff2 = (T_NLa − T_NLb)/T_NLa.
