Power line is an efficient media for home area networking communication scenarios. However, it is not designed to transmit data. This causes several perturbations phenomenon for communications technologies over the po...Power line is an efficient media for home area networking communication scenarios. However, it is not designed to transmit data. This causes several perturbations phenomenon for communications technologies over the power cables. This work presents an investigation of the indoor narrowband power lines channel behavior. The load, the transmission line length and the network topology impact are studied using a simple network. A channel response measure campaign has been realized in 13 sites. The channel capacity has been used for channel classification. The measures were classified into 5 classes. It is shown that channel response is mainly impacted by the load impedance. The class distributions are more impacted by the nature of appliances connected into the indoor network.展开更多
Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using bina...Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using binary classification(LOS/NLOS)oversimplify real-world complexities,with limited generalisation and adaptability to varying indoor environments,thereby reducing the accuracy of positioning.This study proposes an extreme gradient boosting(XGBoost)model to identify multi-class NLOS conditions.We optimise the model using grid search and genetic algorithms.Initially,the grid search approach is used to identify the most favourable values for integer hyperparameters.In order to achieve an optimised model configuration,the genetic algorithm is employed to fine-tune the floating-point hyperparameters.The model evaluations utilise a wide-ranging dataset of real-world measurements obtained with a Qorvo DW1000 UWB device,covering various indoor scenarios.Experimental results show that our proposed XGBoost achieved the highest overall accuracy of 99.47%,precision of 99%,recall of 99%,and an F-score of 99%on an open-source dataset.Additionally,based on a local dataset,the model achieved the highest performance,with an accuracy of 96%,precision of 96%,recall of 97%,and an F-score of 97%.In contrast to current machine learning methods in the literature,the suggestion model enhances classification accuracy and effectively addresses the NLOS/LOS identification as a multiclass propagation channel.This approach provides a robust solution with generalisation and adaptability across various dataset types and environments for more reliable and accurate indoor positioning technologies.展开更多
Objective:To study the position and the grade of screw perforation in the apical region of adolescent idiopathic scoliosis(AIS)surgery using a calibration technique for the intraoperative navigation error,and to analy...Objective:To study the position and the grade of screw perforation in the apical region of adolescent idiopathic scoliosis(AIS)surgery using a calibration technique for the intraoperative navigation error,and to analyze the related factors of navigation deviation and the clinical significance of the calibration technique.Methods:From 2017 to 2020,a total of 60 Lenke 1 AIS surgical cases were enrolled in this research.The 30 cases received surgery using the intraoperative navigation system(Navigation group)and another 30 cases were assisted with intraoperative navigation system with calibration technique(Calibration group)for the intraoperative navigation error.The basic information and radiological data of the both groups were all recorded.According to the Fu Chang-feng’s pedicle channel classification system,the pedicle on the apical region of the two groups was classified.And then the accuracy of screw placement of the two groups was evaluated according to the Rao’s classification.Results:A total of 600 screws were placed in the two groups.The 297 and 303 pedicle screws were implanted in the navigation group and the calibration group,respectively.In the apical region of the calibration group,the rates of the grade 0 screw placement in type A,B and C pedicle were 95.7%,86.7%and 68.9%respectively.It was a statistically significant difference from the 73.9%,66.9%and 30.0%in the navigation group respectively(P<0.05).In the calibration group,the rates of the medial cortical perforation in the type A,B,C and D pedicle were 0%,1.6%,1.6%and 0%,respectively.The corresponding rates were 16.3%,16.9%,30.0%and 47.6%in the navigation group,respectively.Moreover,in the concave side of the apical region of the calibration group,the rates of the medial cortical perforation in the type A,B,C and D pedicle were 0%,3.6%,2.6%and 0%,respectively.Compared with the calibration group,the corresponding rates were higher in the navigation group(34.4%,25.9%,37.2%and 60.0%,respectively).No serious complications such as spinal cord or neurovascular injury occurred for the two groups.Conclusion:Compared with the intraoperative navigation system,the calibration technique for the intraoperative navigation error could provide the higher accuracy of pedicle screw placement in the apical region of the major curve,the lower medial cortical perforation rate,the less screws misplacement rate on the concave side and the less complication rate of the severe Lenke 1 AIS patients.展开更多
文摘Power line is an efficient media for home area networking communication scenarios. However, it is not designed to transmit data. This causes several perturbations phenomenon for communications technologies over the power cables. This work presents an investigation of the indoor narrowband power lines channel behavior. The load, the transmission line length and the network topology impact are studied using a simple network. A channel response measure campaign has been realized in 13 sites. The channel capacity has been used for channel classification. The measures were classified into 5 classes. It is shown that channel response is mainly impacted by the load impedance. The class distributions are more impacted by the nature of appliances connected into the indoor network.
文摘Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using binary classification(LOS/NLOS)oversimplify real-world complexities,with limited generalisation and adaptability to varying indoor environments,thereby reducing the accuracy of positioning.This study proposes an extreme gradient boosting(XGBoost)model to identify multi-class NLOS conditions.We optimise the model using grid search and genetic algorithms.Initially,the grid search approach is used to identify the most favourable values for integer hyperparameters.In order to achieve an optimised model configuration,the genetic algorithm is employed to fine-tune the floating-point hyperparameters.The model evaluations utilise a wide-ranging dataset of real-world measurements obtained with a Qorvo DW1000 UWB device,covering various indoor scenarios.Experimental results show that our proposed XGBoost achieved the highest overall accuracy of 99.47%,precision of 99%,recall of 99%,and an F-score of 99%on an open-source dataset.Additionally,based on a local dataset,the model achieved the highest performance,with an accuracy of 96%,precision of 96%,recall of 97%,and an F-score of 97%.In contrast to current machine learning methods in the literature,the suggestion model enhances classification accuracy and effectively addresses the NLOS/LOS identification as a multiclass propagation channel.This approach provides a robust solution with generalisation and adaptability across various dataset types and environments for more reliable and accurate indoor positioning technologies.
基金National Natural Science Foundation of China(81902270)Young Talents’Science and Technology Innovation Project of Hainan Association for Science and Technology(QCXM202014)。
文摘Objective:To study the position and the grade of screw perforation in the apical region of adolescent idiopathic scoliosis(AIS)surgery using a calibration technique for the intraoperative navigation error,and to analyze the related factors of navigation deviation and the clinical significance of the calibration technique.Methods:From 2017 to 2020,a total of 60 Lenke 1 AIS surgical cases were enrolled in this research.The 30 cases received surgery using the intraoperative navigation system(Navigation group)and another 30 cases were assisted with intraoperative navigation system with calibration technique(Calibration group)for the intraoperative navigation error.The basic information and radiological data of the both groups were all recorded.According to the Fu Chang-feng’s pedicle channel classification system,the pedicle on the apical region of the two groups was classified.And then the accuracy of screw placement of the two groups was evaluated according to the Rao’s classification.Results:A total of 600 screws were placed in the two groups.The 297 and 303 pedicle screws were implanted in the navigation group and the calibration group,respectively.In the apical region of the calibration group,the rates of the grade 0 screw placement in type A,B and C pedicle were 95.7%,86.7%and 68.9%respectively.It was a statistically significant difference from the 73.9%,66.9%and 30.0%in the navigation group respectively(P<0.05).In the calibration group,the rates of the medial cortical perforation in the type A,B,C and D pedicle were 0%,1.6%,1.6%and 0%,respectively.The corresponding rates were 16.3%,16.9%,30.0%and 47.6%in the navigation group,respectively.Moreover,in the concave side of the apical region of the calibration group,the rates of the medial cortical perforation in the type A,B,C and D pedicle were 0%,3.6%,2.6%and 0%,respectively.Compared with the calibration group,the corresponding rates were higher in the navigation group(34.4%,25.9%,37.2%and 60.0%,respectively).No serious complications such as spinal cord or neurovascular injury occurred for the two groups.Conclusion:Compared with the intraoperative navigation system,the calibration technique for the intraoperative navigation error could provide the higher accuracy of pedicle screw placement in the apical region of the major curve,the lower medial cortical perforation rate,the less screws misplacement rate on the concave side and the less complication rate of the severe Lenke 1 AIS patients.
