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Operational performance of several cranes
| MH-3 | MH-4 | AH | LT | CT-3 | CT-4 | |
|---|---|---|---|---|---|---|
| Operating hours | 1.8983956 | 1.5413483 | 0.1719212 | 2.7106885 | 0.7127384 | 0.68275827 |
| No of operation | 533 | 315 | 49 | 648 | 290 | 192 |
| Pulsating operation | 112 | 58 | 2 | 215 | 39 | 25 |
| Backtracking operation | 6 | 6 | 1 | 1 | 10 | 1 |
| Load (kN) | 147.15 | 4,905 | 1,962 | 1,471.5 | 981 | 1,471.5 |
| Lifting Speed (m/min) | 20 | 30 | 20 | 40 | 50 | 60 |
| Current (A) | 100 | 200 | 150 | 100 | 300 | 400 |
| Torque(Nm) | 20,000 | 30,000 | 5,000 | 10,000 | 20,000 | 30,000 |
| Voltage (V) | 690 | 690 | 400 | 400 | 690 | 690 |
| Displacement (mm) | 30 | 40 | 10 | 30 | 40 | 45 |
| Change in length(mm) | 10 | 15 | 5 | 10 | 15 | 20 |
| Noise (dB) | 80 | 85 | 80 | 95 | 85 | 90 |
| Vibration (Hz) | 1 | 2 | 0.5 | 0.5 | 1 | 1.5 |
Existing works comparison
| Author | Objectives | Applications | Parameters used | Methodology | Outcome | Limitations |
|---|---|---|---|---|---|---|
| Yi et al. [34] | Examine intelligent case designs and models for shipyards. | Shipyards with intelligent factories | Case studies and smart factory specifications | Establishing frameworks and analyzing cases | established a framework for the integration of smart technology in shipbuilding | restricted to Chinese shipyards; might not be relevant in other contexts |
| Schwendemann et al. [35] | Examine ML methods for predictive maintenance and bearing condition monitoring. | machines for grinding | Numerous ML techniques with condition data | review of the literature and a comparison of methods | thorough review of ML methods for bearings | restricted to grinding machine bearings; might not apply to other parts |
| Serradilla et al. [36] | Models using DL for predictive maintenance. | Predictive general maintenance | historical maintenance data and DL models | Review of literature, comparison of models, and identification of challenges | Perspectives on DL models, obstacles, and potential paths forward | mostly concentrates on DL; it might not cover other ML methods |
| Ayvaz et al. [37] | Provide a manufacturing line predictive maintenance solution that operates in real time. | production lines for manufacturing | ML algorithms, real-time operational data, and IoT data | Real-time data gathering and predictive ML | Increased production line efficiency and real-time predictive maintenance | Problems with the integration and processing of real-time data |
| Lang et al. [38] | Use ML models using physics knowledge to forecast ship speed. | Prediction of ship speed | Ship characteristics, outside circumstances, and physics-based ML methods | combining ML and physics-based models to accelerate prediction | increased speed prediction accuracy and improved physical constraint management | Complexity of combining ML with physics-based models |
Cross validation and statistical significance performances
| Algorithm | R2 (mean ± std) | MAE (mean ± std) | RMSE (mean ± std) | Statistical significance (p-value) |
|---|---|---|---|---|
| BiLSTM-SPAN (proposed) | 0.910 ± 0.008 | 2.51 ± 0.10 | 0.910 ± 0.10 | - |
| RF | 0.841 ± 0.0013 | 3.18 ± 0.14 | 0.841 ± 0.17 | 0.013 |
| XGBoost | 0.859 ± 0.0011 | 3.35 ± 0.16 | 0.859 ± 0.19 | 0.016 |
| Gradient boosting | 0.878 ± 0.009 | 2.98 ± 0.12 | 0.878 ± 0.15 | 0.008 |
| MLP regressor | 0.865 ± 0.0010 | 3.12 ± 0.14 | 0.865 ± 0.17 | 0.012 |
| SVR | 0.872 ± 0.0011 | 3.05 ± 0.13 | 0.872 ± 0.16 | 0.010 |
| AdaBoost | 0.857 ± 0.0012 | 3.21 ± 0.15 | 0.857 ± 0.18 | 0.014 |
Comparison of prediction result
| Algorithm | R2 | MAE | MAPE | RMSE |
|---|---|---|---|---|
| BiLSTM (proposed) | 0.910 | 35.40 | 2.10 | 120.00 |
| RF | 0.892 | 41.87 | 2.37 | 127.17 |
| XGBoost | 0.889 | 71.02 | 4.19 | 147.38 |
| Gradient boosting | 0.767 | 285.31 | 33.99 | 432.85 |
| MLP regressor | 0.654 | 378.28 | 20.29 | 533.47 |
| SVR | 0.341 | 593.55 | 32.77 | 798.11 |
| AdaBoost | 0.327 | 692.89 | 37.23 | 889.45 |
Results of displacement
| Days | MH-3 | MH-4 | AH | LT | CT-3 | CT-4 |
|---|---|---|---|---|---|---|
| 1 | 6,215.773 | 9,324.361 | 12,297.11 | 14,999.12 | 17,161.76 | 18,783.39 |
| 2 | 8,511.442 | 11,079.25 | 15,399.62 | 16,347.21 | 18,103.97 | 19,859.8 |
| 3 | 10,536.37 | 12,699.25 | 15,393.54 | 17,423.62 | 18,909.17 | 20,666.17 |
| 4 | 12,966.48 | 14,181.3 | 12,957.13 | 17,148.67 | 17,551.5 | 19,175.47 |
| 5 | 13,637.71 | 12,152.39 | 10,789.58 | 15,388.63 | 15,249.52 | 18,359.51 |
| 6 | 11,471.57 | 11,068.97 | 12,948.01 | 13,493.69 | 16,733.44 | 18,084.56 |
| 7 | 8,088.968 | 8,902.588 | 15,510.67 | 14,166.33 | 17,945.92 | 19,972.02 |
| 8 | 6,328.23 | 7,276.751 | 17,126.93 | 16,054.26 | 19,696.84 | 20,912.59 |
| 9 | 8,890.664 | 9,031.411 | 15,227.54 | 17,671.91 | 18,878.55 | 19,962.67 |
| 10 | 11,996.45 | 11,055.17 | 13,059.76 | 18,612.95 | 17,792.08 | 19,281.38 |
| 11 | 14,019.51 | 13,889.75 | 16,298.81 | 17,663.26 | 17,248.03 | 18,735.46 |
| 12 | 13,472.42 | 15,371.1 | 16,159 | 16,847.77 | 19,136.43 | 20,623.62 |
| 13 | 10,901.33 | 15,365.25 | 13,990.75 | 15,762.24 | 20,620.35 | 22,105.9 |
| 14 | 9,277.367 | 12,522.96 | 13,039.89 | 17,919.74 | 19,939.99 | 21,560.45 |
| 15 | 11,030.16 | 10,627.55 | 11,953.66 | 17,780.16 | 18,044.82 | 19,799.01 |
| 16 | 13,863.8 | 13,191.63 | 12,894.7 | 16,695.57 | 17,230.5 | 18,577.18 |
| 17 | 13,046.67 | 15,621.5 | 16,132.35 | 15,338.83 | 16,414.07 | 18,705.77 |
| 18 | 10,069.24 | 13,724.92 | 17,072.92 | 15,064.12 | 16,544.07 | 20,864.43 |
| 19 | 9,658.225 | 11,422.94 | 15,308.67 | 14,519.13 | 18,837.16 | 22,075.28 |
| 20 | 8,300.322 | 11,147.99 | 13,681.9 | 15,730.91 | 20,050.34 | 21,933.59 |
| 21 | 10,323.62 | 10,330.86 | 13,002.72 | 17,753.27 | 21,126.05 | 20,849.23 |
| 22 | 13,563.83 | 10,461.56 | 14,348.46 | 18,965.05 | 19,500.68 | 19,628.34 |
| 23 | 13,559.16 | 12,486.25 | 15,830.28 | 17,475.05 | 18,550.29 | 18,947.98 |
| 24 | 11,932.39 | 14,915.42 | 16,500.81 | 16,931 | 17,329.16 | 19,889.02 |
| 25 | 9,900.207 | 15,585.96 | 16,361.47 | 16,116.68 | 16,649.51 | 20,695.86 |
| 26 | 8,679.31 | 14,231.33 | 14,736.33 | 15,301.89 | 18,131.79 | 21,231.96 |
| 27 | 9,755.018 | 12,605.02 | 13,112.84 | 14,757.38 | 19,074.47 | 20,958.19 |
| 28 | 12,318.62 | 11,519.5 | 14,326.95 | 16,644.13 | 19,203.29 | 20,684.87 |
| 29 | 14,068.6 | 10,569.11 | 16,218.85 | 17,721.24 | 19,198.85 | 20,005.69 |
| 30 | 12,033.85 | 12,728.94 | 17,434.14 | 17,439.51 | 19,192.07 | 21,759.41 |
| 31 | 10,270.54 | 12,702.52 | 17,432.73 | 18,918.76 | 20,405.48 | 22,432.52 |