## 4 Experimental Results and Discussions
### Experiment Comparison of BBO, OBBO, ROBBO and COOBBO
 } & \multirow{2}{*}{**BBO**} & \multirow{2}{*}{**OBBO**} & \multirow{2}{*}{**COOBBO**} & \multirow{2}{*}{**ROBBO**} \\ \hline \multirow{4}{*}{berlin52} & BS & \(8604.2732\pm 271.0828\) & \(8802.2257\pm 298.9179\) & \(\mathbf{8321.864\pm 243.0838}\) & \(8816.3923\pm 310.225\) \\  & CT & \(16.5043\pm\mathbf{0.033254}\) & \(12.8949\pm 0.14883\) & \(26.0636\pm 0.40613\) & \(\mathbf{12.7935\pm 0.15288}\) \\  & UR & - & \(1.39\pm 0.15792\) & \(\mathbf{17.7021\pm 1.5387}\) & \(0.98298\pm\mathbf{0.13792}\) \\  & PD & \(30.9672\pm\mathbf{0.2238}\) & \(32.0102\pm 0.30895\) & \(\mathbf{23.4455\pm 1.7748}\) & \(31.8362\pm 0.29218\) \\ \hline \multirow{4}{*}{bier127} & BS & \(22444.6936\pm\mathbf{7873.8039}\) & \(247079.3802\pm 8659.568\) & \(\mathbf{186999.418\pm 11339.7602}\) & \(247017.627\pm 8644.1022\) \\  & CT & \(36.2248\pm\mathbf{0.18711}\) & \(28.0967\pm 0.32596\) & \(77.5242\pm 1.7217\) & \(\mathbf{27.9017\pm 0.35213}\) \\  & UR & - & \(0.79193\pm 0.12519\) & \(\mathbf{10.0663\pm 0.94305}\) & \(0.73474\pm\mathbf{0.11112}\) \\  & PD & \(\mathbf{37.4125\pm 0.46407}\) & \(40.0844\pm 0.74797\) & \(37.8905\pm 1.7826\) & \(39.9542\pm 0.77365\) \\ \hline \multirow{4}{*}{ch130} & BS & \(14160.151\pm\mathbf{556.0656}\) & \(16163.1156\pm 571.0329\) & \(\mathbf{10735.6857\pm 800.823}\) & \(16110.5935\pm 580.3632\) \\  & CT & \(36.8155\pm\mathbf{0.041028}\) & \(28.6327\pm 0.28465\) & \(80.0928\pm 1.9244\) & \(\mathbf{28.4332\pm 0.28853}\) \\  & UR & - & \(0.79987\pm 0.11519\) & \(\mathbf{11.046\pm 1.133}\) & \(0.72923\pm\mathbf{0.10295}\) \\  & PD & \(\mathbf{37.108\pm 0.45369}\) & \(39.7573\pm 0.65399\) & \(38.2925\pm 1.7171\) & \(39.6187\pm 0.6568\) \\ \hline \multirow{4}{*}{kroA150} & BS & \(76274.6154\pm\mathbf{3082.4458}\) & \(86542.4877\pm\mathbf{3231.4578}\) & \(\mathbf{54089.9955\pm 4138.1095}\) & \(87258.7988\pm 3590.0721\) \\  & CT & \(42.0813\pm\mathbf{0.039008}\) & \(32.634\pm 0.43444\) & \(97.9435\pm 2.3961\) & \(\mathbf{32.4983\pm 0.39877}\) \\  & UR & - & \(0.84709\pm\mathbf{0.11022}\) & \(\mathbf{11.5362\pm 1.14}\) & \(0.71816\pm 0.11195\) \\  & PD & \(\mathbf{38.4352\pm 0.49502}\) & \(41.6914\pm 0.89549\) & \(43.8533\pm 2.3142\) & \(41.3216\pm 0.78642\) \\ \hline \multirow{4}{*}{kroA200} & BS & \(121550.466\pm\mathbf{3586.8735}\) & \(136496.701\pm 4039.3472\) & \(\mathbf{79433.7261\pm 5793.0264}\) & \(136436.9172\pm 4140.0182\) \\  & CT & \(55.3055\pm\mathbf{0.060966}\) & \(42.9461\pm 0.60204\) & \(146.7581\pm 3.6105\) & \(\mathbf{42.702\pm 0.50824}\) \\  & UR & - & \(0.77342\pm 0.1136\) & \(\mathbf{9.8554\pm 0.92318}\) & \(0.68909\pm\mathbf{0.10748}\) \\  & PD & \(\mathbf{40.8049\pm 0.5737}\) & \(45.0263\pm 1.3084\) & \(51.4226\pm 2.5032\) & \(44.635\pm 1.2792\) \\ \hline \multirow{4}{*}{kroC100} & BS & \(38808.7544\pm\mathbf{1553.4899}\) & \(43909.6763\pm 2211.9766\) & \(\mathbf{28786.3067\pm 2089.1848}\) & \(44319.1631\pm 2033.1415\) \\  & CT & \(28.9781\pm\mathbf{0.035912}\) & \(22.5343\pm 0.2427\) & \(56.7792\pm 1.2044\) & \(\mathbf{22.4417\pm 0.25442}\) \\  & UR & - & \(0.98634\pm 0.14493\) & \(\mathbf{15.161}\pm 1.4206\) & \(0.75694\pm\mathbf{0.10583}\) \\  & PD & \(\mathbf{35.8608\pm 0.34445}\) & \(38.3319\pm 0.6626\) & \(36.5919\pm 2.2458\) & \(37.8325\pm 0.59057\) \\ \hline \multirow{4}{*}{lin105} & BS & \(28658.7352\pm\mathbf{1455.8463}\) & \(32433.6636\pm 1562.2038\) & \(\mathbf{20653.0943\pm 1528.6458}\) & \(32414.3953\pm 1534.0982\) \\  & CT & \(30.2712\pm\mathbf{0.037719}\) & \(23.576\pm 0.28172\) & \(60.3434\pm 1.2413\) & \(\mathbf{23.4203\pm 0.28112}\) \\  & UR & - & \(0.94954\pm\mathbf{0.11861}\) & \(\mathbf{14.1988\pm 1.4196}\) & \(0.75923\pm 0.11967\) \\  & PD & \(\mathbf{36.3301\pm 0.34626}\) & \(38.8883\pm 0.60563\) & \(38.1673\pm 2.0066\) & \(38.4409\pm 0.56284\) \\ \hline \multirow{4}{*}{lin318} & BS & \(293943.2531\pm 6647.7388\) & \(324536.2956\pm 5997.1132\) & \(\mathbf{179974.0689\pm 11519.3106}\) & \(325160.5952\pm\mathbf{5921.0519}\) \\  & CT & \(86.5313\pm\mathbfBased on the simulation results in Table 2, COOBBO proposed in this paper achieved the best solution among all.