Distribution-Free Model for Ambulance Location Problem with Ambiguous Demand

Table 5

Computational results on instances with data generated from Poisson distribution.

Sampling approach			MIP-DF1	MIP-DF2	Sampling approach			MIP-DF1	MIP-DF2	Sampling approach			MIP-DF1	MIP-DF2
CT	Obj	Sel (%)	Sel (%)	Sel (%)	CT	Obj	Sel (%)	Sel (%)	Sel (%)	CT	Obj	Sel (%)	Sel (%)	Sel (%)
1	(2,6)	2.7	90	72.94	99.67	90.01	2.7	98	77.70	99.79	90.13	2.4	103	92.73	99.99	94.68
2	(4,12)	4.6	170	79.61	99.21	91.17	5.1	183	83.05	99.46	91.28	4.9	201	93.92	99.98	95.46
3	(6,18)	6.8	258	75.78	99.38	89.11	7.4	280	80.28	99.68	90.04	6.9	307	91.82	99.99	96.58
4	(8,24)	9.3	315	80.01	99.28	91.96	10.2	338	84.38	99.67	91.72	9.2	368	94.68	99.99	96.13
5	(10,30)	12.0	413	80.41	99.39	94.49	13.3	443	84.47	99.76	92.72	12.1	479	95.44	99.99	97.52
6	(12,36)	15.5	476	80.84	98.77	95.54	16.7	508	88.63	99.91	95.69	15.9	536	94.56	99.99	97.34
7	(14,42)	19.5	573	78.76	98.92	96.63	21.3	609	91.24	99.98	97.29	20.5	643	93.14	100.00	97.68
8	(16,48)	23.2	687	79.64	99.97	97.88	26.7	724	85.23	99.88	96.87	23.8	772	94.22	99.98	96.89
9	(18,54)	29.3	692	82.67	98.93	98.09	32.7	730	83.86	99.99	97.50	29.8	757	92.28	99.99	97.55
10	(20,60)	35.6	796	79.46	98.99	98.01	39.9	840	82.99	99.76	96.86	36.0	885	96.68	99.99	97.05
11	(22,66)	42.3	829	82.01	98.95	97.56	48.9	877	83.78	99.87	97.88	44.8	927	94.76	99.99	98.12
12	(24,72)	51.2	1023	83.38	99.13	98.53	55.4	1085	85.01	99.99	98.81	51.4	1148	93.98	99.99	98.88
13	(26,78)	59.2	1045	84.16	99.07	98.73	68.7	1088	79.98	99.96	98.02	60.7	1152	95.04	99.99	98.21
14	(28,84)	72.3	1099	79.46	99.15	97.88	83.8	1166	80.56	99.92	98.29	77.6	1230	95.46	99.99	98.39
15	(30,90)	85.5	1089	79.15	99.64	97.03	94.2	1156	84.32	99.84	97.78	90.3	1225	92.23	99.98	97.85
16	(32,96)	100.9	1158	80.24	98.97	97.69	116.3	1231	85.00	99.96	98.24	104.5	1222	91.99	99.99	98.35
17	(34,102)	116.5	1299	80.34	99.19	97.79	128.5	1375	84.95	99.37	98.08	119.0	1457	92.58	100.00	98.46
18	(36,108)	125.4	1411	81.76	99.43	98.85	147.9	1492	85.61	99.68	98.68	134.5	1579	92.86	99.99	98.75
19	(38,114)	150.4	1506	79.70	99.23	98.42	165.1	1594	81.67	99.72	98.46	156.4	1694	93.76	99.99	97.86
20	(40,120)	170.6	1635	78.19	99.16	97.83	185.4	1734	86.07	99.68	97.76	177.8	1825	92.85	99.04	97.18
21	(42,126)	205.4	1622	83.54	99.18	98.34	235.7	1720	82.97	99.78	98.33	222.6	1856	95.01	99.99	98.34
22	(44,132)	240.0	1736	84.94	99.22	98.46	285.2	1844	82.69	99.99	98.16	268.0	1946	94.86	99.99	98.20
23	(46,138)	265.1	1934	81.41	99.53	97.93	315.9	2049	84.92	99.69	97.99	307.2	2172	93.58	100.00	98.13
24	(48,144)	300.4	1961	82.26	99.47	96.81	352.2	2086	85.13	99.98	97.06	310.2	2209	94.88	99.99	97.24
25	(50,150)	330.8	1924	81.11	99.65	97.46	389.8	2038	82.64	99.99	97.88	363.9	2161	95.46	99.99	98.13
26	(52,156)	366.9	1911	80.96	99.39	98.55	430.5	2027	87.22	99.67	98.74	445.3	2142	91.85	99.99	98.76
27	(54,162)	441.8	2095	83.87	99.27	97.54	477.1	2219	83.41	99.89	97.49	480.6	2353	92.89	99.99	97.55
28	(56,168)	536.7	2113	84.58	99.68	98.48	535.6	2237	84.52	99.78	98.55	522.1	2369	92.28	100.00	98.68
29	(58,174)	621.7	2186	79.98	99.89	96.94	594.2	2315	83.16	99.96	96.99	585.3	2371	91.67	99.99	97.05
30	(60,180)	726.3	2382	83.21	99.91	98.37	652.7	2543	83.59	99.98	98.86	621.4	2678	93.69	99.97	98.86
31	(62,186)	821.4	2346	84.04	99.36	98.88	781.3	2430	83.21	99.99	98.46	687.6	2560	93.58	99.99	98.47
32	(64,192)	886.3	2518	83.78	99.38	98.07	810.6	2677	83.56	99.99	98.33	787.7	2822	94.08	100.00	98.35
33	(66,198)	998.5	2532	84.06	99.17	97.09	968.4	2689	84.97	99.96	97.46	808.8	2838	95.07	99.99	97.49
34	(68,204)	1126.4	2534	85.43	99.08	98.97	1098.6	2685	88.09	99.96	97.82	846.9	2843	88.44	99.98	97.80
35	(70,210)	1203.5	2715	82.58	99.37	97.99	1209.8	2886	85.69	99.91	98.09	994.6	3041	94.59	99.99	98.13
36	(72,216)	1280.3	2825	81.04	99.29	98.27	1307.6	3010	86.51	99.94	98.34	1101.3	3170	94.68	99.99	98.65
37	(74,222)	1302.1	2830	82.28	99.49	98.26	1326.1	3009	83.76	99.99	98.26	1201.4	3172	93.46	99.99	98.88
38	(76,228)	1386.2	2843	81.52	99.33	98.07	1399.5	3028	87.60	99.98	98.41	1213.3	3187	97.06	99.99	98.76
39	(78,234)	1538.7	2953	83.12	99.64	97.99	1482.7	3133	90.01	99.95	97.83	1338.1	3304	89.13	99.99	97.99
40	(80,240)	1697.4	2975	85.10	99.85	97.67	1525.6	3249	82.17	99.93	97.81	1586.7	3347	91.11	99.99	97.91
Average		435.2	1587.5	81.43	99.34	97.08	436.2	1685.6	84.37	99.85	97.07	396.8	1776.3	93.56	99.97	97.81