Accurate and rapid determination of source locations is of great significance for surface microseismic monitoring.Traditional methods,such as diffraction stacking,are time-consuming and challenging for real-time monit...Accurate and rapid determination of source locations is of great significance for surface microseismic monitoring.Traditional methods,such as diffraction stacking,are time-consuming and challenging for real-time monitoring.In this study,we propose an approach to locate microseismic events using a deep learning algorithm with surface data.A fully convolutional network is designed to predict source locations.The input data is the waveform of a microseismic event,and the output consists of three 1D Gaussian distributions representing the probability distribution of the source location in the x,y,and z dimensions.The theoretical dataset is generated to train the model,and several data augmentation methods are applied to reduce discrepancies between the theoretical and field data.After applying the trained model to field data,the results demonstrate that our method is fast and achieves comparable location accuracy to the traditional diffraction stacking location method,making it promising for real-time microseismic monitoring.展开更多
BACKGROUND Major hip surgery usually requires neuraxial or general anesthesia with tracheal intubation and may be supplemented with a nerve block to provide intraoperative and postoperative pain relief.CASE SUMMARY Th...BACKGROUND Major hip surgery usually requires neuraxial or general anesthesia with tracheal intubation and may be supplemented with a nerve block to provide intraoperative and postoperative pain relief.CASE SUMMARY This report established that hip surgical procedures can be performed with a fascia iliaca compartment block(FICB)and monitored anesthesia care(MAC)while avoiding neuraxial or general anesthesia.This was a preliminary experience with two geriatric patients with hip fracture,American Society of Anesthesiologists status III,and with many comorbidities.Neither patient could be operated on within 48 h after admission.Both general anesthesia and neuraxial anesthesia were high-risk procedures and had contraindications.Hence,we chose nerve block combined with a small amount of sedation.Intraoperative analgesia was provided by single-injection ultrasound-guided FICB.Light intravenous sedation was added.Surgical exposure was satisfactory,and neither patient complained of any symptoms during the procedure.CONCLUSION This report showed that hip surgery for geriatric patients can be performed with FICB and MAC,although complications and contraindications are common.The anesthetic program was accompanied by stable respiratory and circulatory system responses and satisfactory analgesia while avoiding the adverse effects and problems associated with either neuraxial or general anesthesia.展开更多
Restoration of contaminated soil and groundwater could be divided into two phases. The first phase takes aim at reducing human being＇s health risks by active remediation, while the second phase aims at eliminating ec...Restoration of contaminated soil and groundwater could be divided into two phases. The first phase takes aim at reducing human being＇s health risks by active remediation, while the second phase aims at eliminating ecological risks by natural attenuation （NA）. Because of cost-effective and sustainable cleanup, monitored natural attenuation （MNA） and enhanced natural attenuation （ENA） have been gaining more attention recently, especially in the respects of ecological risk-oriented contaminated land management and a follow-up measure after active remediation. The uses and procedures of MNA for contaminated site cleanup and remediation in USA and EU were introduced firstly, and then possible applications of MNA in China were suggested. More developments and practices of MNA and ENA for managing contaminated sites in China are expected.展开更多
Clopidogrel Anergy2003 Germany Müller et at 105 patients with stable coronary artery disease using clopidogrel for PCI,about5%of patients showed no response to the drug,which is defined as platelets in the 20μmo...Clopidogrel Anergy2003 Germany Müller et at 105 patients with stable coronary artery disease using clopidogrel for PCI,about5%of patients showed no response to the drug,which is defined as platelets in the 20μmol/L ADP under the action of its aggregation only on the basis of the inhibition rate of 10%or less.These people postoperative thrombosis,showing the drug has resisters,and postoperative thrombosis related.2004 SchrPat the current展开更多
Rat Liver Cd5Zn2-metallothionein isoforms were titrated with cuprous ion and monitored by 1H NMR Initial replacement occurred in β-domain followed by α-domain.MT exhibited well-defined structure under 10 mole equiva...Rat Liver Cd5Zn2-metallothionein isoforms were titrated with cuprous ion and monitored by 1H NMR Initial replacement occurred in β-domain followed by α-domain.MT exhibited well-defined structure under 10 mole equivalents cuprous ion.展开更多
Objective To summarize the clinical features of intracranial aneurysms of posterior cerebral artery (PCA) ,and the surgical approaches and operative skills to treat them . Methods The aneurysms arose from the P1 segme...Objective To summarize the clinical features of intracranial aneurysms of posterior cerebral artery (PCA) ,and the surgical approaches and operative skills to treat them . Methods The aneurysms arose from the P1 segment in 3 patients,the P2 segment in 5 patients and the P3 segment in 2 patients.展开更多
A comprehensive monitoring program was conducted to measure the rock mass displacements, support response, and stress changes at a longwall tailgate entry in West Virginia.Monitoring was initiated a few days after dev...A comprehensive monitoring program was conducted to measure the rock mass displacements, support response, and stress changes at a longwall tailgate entry in West Virginia.Monitoring was initiated a few days after development of the gateroad entries and continued during passage of the longwall panels on both sides of the entry.Monitoring included overcore stress measurements of the initial stress within the rock mass, changes in cable bolt loading, standing support pressure, roof deformation, rib deformation,stress changes in the coal pillar, and changes in the full three-dimensional stress tensor within the rock mass at six locations around the monitoring site.During the passage of the first longwall, stress measurements in the rock and coal detected minor changes in loading while minor changes were detected in roof deformation.As a result of the relatively favorable stress and geological conditions, the support systems did not experience severe loading or rock deformation until the second panel approached within 10–15 m of the instrumented locations.After reaching the peak loading at about 50–75 mm of roof sag, the cable bolts started to unload, and load was transferred to the standing supports.The standing support system was able to maintain an adequate opening inby the shields to provide ventilation to the first crosscut inby the face, as designed.The results were used to calibrate modeled cable bolt response to field data, and to validate numerical modeling procedures that have been developed to evaluate entry support systems.It is concluded that the support system was more than adequate to control the roof of the tailgate up to the longwall face location.The monitoring results have provided valuable data for the development and validation of support design strategies for longwall tailgate entries.展开更多
This paper analyses the five years’monitored strains collected from a long-term health monitoring system installed on a bridge with wavelet transform.In the analysis,the monitored strains are pre-processed,features o...This paper analyses the five years’monitored strains collected from a long-term health monitoring system installed on a bridge with wavelet transform.In the analysis,the monitored strains are pre-processed,features of the monitored data are summarized briefly.The influences of the base functions on the results of wavelet analysis are studied simultaneously.The results show that the db wavelet is a good mother wavelet function in the analysis,and the order N should be larger than 20,but less than 46 in decomposing the monitored strains of the bridge.According to the strain variation features of concrete bridge,the proper decomposition level is 4 in the wavelet multi-resolution analysis.With the present method,the strains caused by random loads and daily sunlight can be accurately extracted from the monitored strains.The decomposed components of the monitored strains show that the amplitudes of the strains caused by random loads,daily sunlight,and annual temperature effect,are about 5με,25με,and 50μεrespectively.The structural response under random load is smaller than the other parts.展开更多
The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-...The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-arid ecosystems. The present study determined the dynamism of the Zagros forests in Iran using Remote Sensing and Geographic Information System techniques and statistical science. The results show that the density of trees varied from 10 to 53 % according to the physio- graphic and climatic conditions of semi-arid regions. The best and lowest correlation between vegetation indices and forest density were obtained for the global environmental monitoring index （GEMI; R2 = 0.94） and soil adjust vegetation index （R2 = 0.81）, respectively. GEMI is used to monitor land use changes over a 10-year period. Results show that 2720 ha2 of forest have been destroyed by human interference and tillage on steep slopes during this period which also resulted in the loss of the fertile soil layer. GEMI determined the areas with a biomass of trees and could normally separate border regions with low bio- mass density of trees from regions without canopy cover. The results revealed that assessment of forest and vegetation cover in arid and semi-arid arduous forest regions using satellite digital numbers and ordinary sampling is subject to uncertainty. A stratified grouping procedure should be established to increase the accuracy of assessment.展开更多
This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the fres...This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the freshwater tidal part, which embraces the largest seaport of the world: Rotterdam, as well as the largest national park of the Netherlands. It reports especially about a young mans endeavor in half a century real time monitoring of some land(scape) units with simple means.展开更多
In general,the material properties,loads,resistance of the prestressed concrete continuous rigid frame bridge in different construction stages are time-varying.So,it is essential to monitor the internal force state wh...In general,the material properties,loads,resistance of the prestressed concrete continuous rigid frame bridge in different construction stages are time-varying.So,it is essential to monitor the internal force state when the bridge is in construction.Among them,how to assess the safety is one of the challenges.As the continuous monitoring over a long-term period can increase the reliability of the assessment,so,based on a large number of monitored strain data collected from the structural health monitoring system(SHMS)during construction,a calculation method of the punctiform time-varying reliability is proposed in this paper to evaluate the stress state of this type bridge in cantilever construction stage by using the basic reliability theory.At the same time,the optimal stress distribution function in the bridge mid-span base plate is determined when the bridge is closed.This method can provide basis and direction for the internal force control of this type bridge in construction process.So,it can reduce the bridge safety and quality accidents in construction stages.展开更多
When the bridge components needing maintenance are the world problem at present,and the health monitoring system is considered to be a very helpful tool for solving this problem.In this paper,a large number of s...When the bridge components needing maintenance are the world problem at present,and the health monitoring system is considered to be a very helpful tool for solving this problem.In this paper,a large number of strain data acquired from the structural health monitoring system(SHMS)installed on a continuous rigid frame bridge are adopted to do reliability assessment.Firstly,a calculation method of punctiform time-dependent reliability is proposed based on the basic reliability theory,and introduced how to calculate reliability of the bridge by using the stress data transformed from the strain data.Secondly,combined with“Three Sigma”principle and the basic pressure safety reserve requirement,the critical load effects distribution function of the bridge is defined,and then the maintenance reliability threshold for controlling the unfavorable load state which appears in the early operation stage of this type bridge is suggested,and then the combination of bridge maintenance management and health monitoring system is realized.Finally,the transformed stress distribution certifies that the load effects of concrete bridges practically have a normal distribution;as for the concrete continuous rigid frame bridge with C50 strength grade concrete,the retrofit reliability threshold should be valued at 6.13.The methodology suggested in this article can help bridge engineers do effective maintenance of bridges,which can effectively extend the service life of the bridge and bring better economic and social benefits.展开更多
With the development of the monitoring technology,it is more and more common that the system is continuously monitored.Therefore,the research on the maintenance optimization of the continuously monitored deterioration...With the development of the monitoring technology,it is more and more common that the system is continuously monitored.Therefore,the research on the maintenance optimization of the continuously monitored deterioration system is important.The deterioration process of the discussed system is described by a Gamma process.The predictive maintenance is considered to be imperfect and formulated.The expected interval of two continuous preventive maintenances is derived.Then,the maintenance optimization model of the continuously monitored deterioration system is presented.In the model,the minimization of the expected operational cost per unit time and the maximization of the system availability are the optimization objectives.The improved ideal point method with the normalized objective functions is employed to solve the proposed model.The validity and sensitivity of the proposed multiobjective maintenance optimization model are analyzed by a numerical example.展开更多
The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a g...The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a goal of extreme and current interest.In the present work,the results obtained from the processing of experimental data of a real structure are shown.The analyzed structure is a lattice structure approximately 9 m high,monitored with 18 uniaxial accelerometers positioned in pairs on 9 different levels.The data used refer to continuous monitoring that lasted for a total of 1 year,during which minor damage was caused to the structure by alternatively removing some bracings and repositioning them in the structure.Two methodologies detecting damage based on decomposition techniques of the acquired data were used and tested,as well as a methodology combining the two techniques.The results obtained are extremely interesting,as all the minor damage caused to the structure was identified by the processing methods used,based solely on the monitored data and without any knowledge of the real structure being analyzed.The results use 15 acquisitions in environmental conditions lasting 10 min each,a reasonable amount of time to get immediate feedback on possible damage to the structure.展开更多
Background:Awake craniotomy(AC)has become gold standard in surgical resection of gliomas located in eloquent areas.The conscious sedation techniques in AC include both monitored anesthesia care(MAC)and asleep-awake-as...Background:Awake craniotomy(AC)has become gold standard in surgical resection of gliomas located in eloquent areas.The conscious sedation techniques in AC include both monitored anesthesia care(MAC)and asleep-awake-asleep(AAA).The choice of optimal anesthetic method depends on the preferences of the surgical team(mainly anesthesiologist and neurosurgeon).The aim of this study was to compare the difference in physiological and blood gas data,dosage of different drugs,the probability of switching to endotracheal intubation,and extent of tumor resection and dysfunction after operation between AAA and MAC anesthetic management for resection of gliomas in eloquent brain areas.Methods:Two-hundred and twenty-five patients with super-tentorial tumor located in eloquent areas underwent AC from 2009 to 2021 in Xijing Hospital.Forty-one patients underwent AAA technique,and the rest one-hundred eighty-four patients underwent MAC technique.Anesthetic management,dosage of different drugs,intraoperative complications,postoperative outcomes,adverse events,extent of resection and motor,and sensory and language dysfunction after operation were compared between MAC and AAA.Result:There was no significant difference in gender,KPS score,MMSE score,glioma grade,type,and growth site between the patients in the two groups,except the older age of patients in MAC group than that in AAA group.During the whole process of operation,there were greater pulse pressure difference(P=0.046),shorter operation time(P=0.039),less dosage of remifentanil(P=0.000),more dosage of dexmedetomidine(P=0.013),more use of antiemetics(81%,P=0.0067),lower use of vasoactive agent(45.1%,P=0.010),and lower probability of conversion to general anesthesia(GA,P=0.027)in MAC group than that in AAA group.Blood gas analysis showed that PetCO2(P=0.000),Glu concentration(P=0.000),and PaCO2(P=0.000)were higher,but SPO2(P=0.002)and PaO2(P=0.000)were lower in MAC group than that in AAA group.In the postoperative recovery stage,compared with that of AAA group,the probability of dysfunction in MAC group at 1,3,5,and 7 days after operation was lower,which were 27.8%vs 53.6%(P=0.003),31%vs 68.3%(P=0.000),28.8%vs 63.4%(P=0.000),and 25.6%vs 58.5%(P=0.000),respectively.Conclusion:Compared with AAA,it seems that MAC has more advantages in the management for resection of gliomas in eloquent brain areas,and MAC combined with multiple monitoring such as cerebral cortical mapping,neuronavigation,and ultrasonic detection is worthy of popularization for the resection of gliomas in eloquent brain areas.展开更多
To examine stress redistribution phenomena in bridges subjected to varying operational conditions,this study conducts a comprehensive analysis of three years of monitoring data from a 153-m double-deck road–rail stee...To examine stress redistribution phenomena in bridges subjected to varying operational conditions,this study conducts a comprehensive analysis of three years of monitoring data from a 153-m double-deck road–rail steel arch bridge.An initial statistical comparison of sensor data distributions reveals clear temporal variations in stress redistribution patterns.XGBoost(eXtreme Gradient Boosting),a gradient-boosting machine learning(ML)algorithm,was employed not only for predictive modeling but also to uncover the underlying mechanisms of stress evolution.Unlike traditional numerical models that rely on extensive assumptions and idealizations,XGBoost effectively captures nonlinear and time-varying relationships between stress states and operational/environmental factors,such as temperature,traffic load,and structural geometry.This approach allows for the identification of critical periods and conditions under which stress redistribution becomes significant.Results indicate a clear shift of stress concentrations frombeamends toward mid-span regions following the commencement of metro operations,reflecting both structural adaptation and localized overstress near arch ribs.Furthermore,the model generates robust predictions of stress evolution,demonstrating potential applications in early warning systems and fatigue risk assessment.This work represents the first application of interpretable gradient-boosting techniques to stress redistribution modeling in double-deck bridges.In addition,a Stress Redistribution Index(SRI)is proposed,derived from this monitoring study and finite-element-based transverse load distributions,to quantify temporal stress shifts between midspan and edge beams.The results provide both theoretical contributions and practical guidance for the design,inspection,and maintenance of complex bridge structures.展开更多
Motor imbalance is a critical failure mode in rotating machinery,potentially causing severe equipment damage if undetected.Traditional vibration-based diagnostic methods rely on direct sensor contact,leading to instal...Motor imbalance is a critical failure mode in rotating machinery,potentially causing severe equipment damage if undetected.Traditional vibration-based diagnostic methods rely on direct sensor contact,leading to installation challenges and measurement artifacts that can compromise accuracy.This study presents a novel radar-based framework for non-contact motor imbalance detection using 24 GHz continuous-wave radar.A dataset of 1802 experimental trials was sourced,covering four imbalance levels(0,10,20,30 g)across varying motor speeds(500–1500 rpm)and load torques(0–3 Nm).Dual-channel in-phase and quadrature radar signals were captured at 10,000 samples per second for 30-s intervals,preserving both amplitude and phase information for analysis.A multi-domain feature extraction methodology captured imbalance signatures in time,frequency,and complex signal domains.From 65 initial features,statistical analysis using Kruskal–Wallis tests identified significant descriptors,and recursive feature elimination with Random Forest reduced the feature set to 20 dimensions,achieving 69%dimensionality reduction without loss of performance.Six machine learning algorithms,Random Forest,Extra Trees Classifier,Extreme Gradient Boosting,Categorical Boosting,Support Vector Machine with radial basis function kernel,and k-Nearest Neighbors were evaluated with grid-search hyperparameter optimization and five-fold cross-validation.The Extra Trees Classifier achieved the best performance with 98.52%test accuracy,98%cross-validation accuracy,and minimal variance,maintaining per-class precision and recall above 97%.Its superior performance is attributed to its randomized split selection and full bootstrapping strategy,which reduce variance and overfitting while effectively capturing the nonlinear feature interactions and non-normal distributions present in the dataset.The model’s average inference time of 70 ms enables near real-time deployment.Comparative analysis demonstrates that the radar-based framework matches or exceeds traditional contact-based methods while eliminating their inherent limitations,providing a robust,scalable,and noninvasive solution for industrial motor condition monitoring,particularly in hazardous or space-constrained environments.展开更多
An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of a...An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.展开更多
基金supported by National Natural Science Foundation of China Grant(No.42004040,42474092,U2239204,and 42304145)Natural Science Foundation of Jiangxi Province Grant(20242BAB25190 and 20232BAB213077).
文摘Accurate and rapid determination of source locations is of great significance for surface microseismic monitoring.Traditional methods,such as diffraction stacking,are time-consuming and challenging for real-time monitoring.In this study,we propose an approach to locate microseismic events using a deep learning algorithm with surface data.A fully convolutional network is designed to predict source locations.The input data is the waveform of a microseismic event,and the output consists of three 1D Gaussian distributions representing the probability distribution of the source location in the x,y,and z dimensions.The theoretical dataset is generated to train the model,and several data augmentation methods are applied to reduce discrepancies between the theoretical and field data.After applying the trained model to field data,the results demonstrate that our method is fast and achieves comparable location accuracy to the traditional diffraction stacking location method,making it promising for real-time microseismic monitoring.
文摘BACKGROUND Major hip surgery usually requires neuraxial or general anesthesia with tracheal intubation and may be supplemented with a nerve block to provide intraoperative and postoperative pain relief.CASE SUMMARY This report established that hip surgical procedures can be performed with a fascia iliaca compartment block(FICB)and monitored anesthesia care(MAC)while avoiding neuraxial or general anesthesia.This was a preliminary experience with two geriatric patients with hip fracture,American Society of Anesthesiologists status III,and with many comorbidities.Neither patient could be operated on within 48 h after admission.Both general anesthesia and neuraxial anesthesia were high-risk procedures and had contraindications.Hence,we chose nerve block combined with a small amount of sedation.Intraoperative analgesia was provided by single-injection ultrasound-guided FICB.Light intravenous sedation was added.Surgical exposure was satisfactory,and neither patient complained of any symptoms during the procedure.CONCLUSION This report showed that hip surgery for geriatric patients can be performed with FICB and MAC,although complications and contraindications are common.The anesthetic program was accompanied by stable respiratory and circulatory system responses and satisfactory analgesia while avoiding the adverse effects and problems associated with either neuraxial or general anesthesia.
文摘Restoration of contaminated soil and groundwater could be divided into two phases. The first phase takes aim at reducing human being＇s health risks by active remediation, while the second phase aims at eliminating ecological risks by natural attenuation （NA）. Because of cost-effective and sustainable cleanup, monitored natural attenuation （MNA） and enhanced natural attenuation （ENA） have been gaining more attention recently, especially in the respects of ecological risk-oriented contaminated land management and a follow-up measure after active remediation. The uses and procedures of MNA for contaminated site cleanup and remediation in USA and EU were introduced firstly, and then possible applications of MNA in China were suggested. More developments and practices of MNA and ENA for managing contaminated sites in China are expected.
文摘Clopidogrel Anergy2003 Germany Müller et at 105 patients with stable coronary artery disease using clopidogrel for PCI,about5%of patients showed no response to the drug,which is defined as platelets in the 20μmol/L ADP under the action of its aggregation only on the basis of the inhibition rate of 10%or less.These people postoperative thrombosis,showing the drug has resisters,and postoperative thrombosis related.2004 SchrPat the current
文摘Rat Liver Cd5Zn2-metallothionein isoforms were titrated with cuprous ion and monitored by 1H NMR Initial replacement occurred in β-domain followed by α-domain.MT exhibited well-defined structure under 10 mole equivalents cuprous ion.
文摘Objective To summarize the clinical features of intracranial aneurysms of posterior cerebral artery (PCA) ,and the surgical approaches and operative skills to treat them . Methods The aneurysms arose from the P1 segment in 3 patients,the P2 segment in 5 patients and the P3 segment in 2 patients.
文摘A comprehensive monitoring program was conducted to measure the rock mass displacements, support response, and stress changes at a longwall tailgate entry in West Virginia.Monitoring was initiated a few days after development of the gateroad entries and continued during passage of the longwall panels on both sides of the entry.Monitoring included overcore stress measurements of the initial stress within the rock mass, changes in cable bolt loading, standing support pressure, roof deformation, rib deformation,stress changes in the coal pillar, and changes in the full three-dimensional stress tensor within the rock mass at six locations around the monitoring site.During the passage of the first longwall, stress measurements in the rock and coal detected minor changes in loading while minor changes were detected in roof deformation.As a result of the relatively favorable stress and geological conditions, the support systems did not experience severe loading or rock deformation until the second panel approached within 10–15 m of the instrumented locations.After reaching the peak loading at about 50–75 mm of roof sag, the cable bolts started to unload, and load was transferred to the standing supports.The standing support system was able to maintain an adequate opening inby the shields to provide ventilation to the first crosscut inby the face, as designed.The results were used to calibrate modeled cable bolt response to field data, and to validate numerical modeling procedures that have been developed to evaluate entry support systems.It is concluded that the support system was more than adequate to control the roof of the tailgate up to the longwall face location.The monitoring results have provided valuable data for the development and validation of support design strategies for longwall tailgate entries.
文摘This paper analyses the five years’monitored strains collected from a long-term health monitoring system installed on a bridge with wavelet transform.In the analysis,the monitored strains are pre-processed,features of the monitored data are summarized briefly.The influences of the base functions on the results of wavelet analysis are studied simultaneously.The results show that the db wavelet is a good mother wavelet function in the analysis,and the order N should be larger than 20,but less than 46 in decomposing the monitored strains of the bridge.According to the strain variation features of concrete bridge,the proper decomposition level is 4 in the wavelet multi-resolution analysis.With the present method,the strains caused by random loads and daily sunlight can be accurately extracted from the monitored strains.The decomposed components of the monitored strains show that the amplitudes of the strains caused by random loads,daily sunlight,and annual temperature effect,are about 5με,25με,and 50μεrespectively.The structural response under random load is smaller than the other parts.
文摘The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-arid ecosystems. The present study determined the dynamism of the Zagros forests in Iran using Remote Sensing and Geographic Information System techniques and statistical science. The results show that the density of trees varied from 10 to 53 % according to the physio- graphic and climatic conditions of semi-arid regions. The best and lowest correlation between vegetation indices and forest density were obtained for the global environmental monitoring index （GEMI; R2 = 0.94） and soil adjust vegetation index （R2 = 0.81）, respectively. GEMI is used to monitor land use changes over a 10-year period. Results show that 2720 ha2 of forest have been destroyed by human interference and tillage on steep slopes during this period which also resulted in the loss of the fertile soil layer. GEMI determined the areas with a biomass of trees and could normally separate border regions with low bio- mass density of trees from regions without canopy cover. The results revealed that assessment of forest and vegetation cover in arid and semi-arid arduous forest regions using satellite digital numbers and ordinary sampling is subject to uncertainty. A stratified grouping procedure should be established to increase the accuracy of assessment.
文摘This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the freshwater tidal part, which embraces the largest seaport of the world: Rotterdam, as well as the largest national park of the Netherlands. It reports especially about a young mans endeavor in half a century real time monitoring of some land(scape) units with simple means.
文摘In general,the material properties,loads,resistance of the prestressed concrete continuous rigid frame bridge in different construction stages are time-varying.So,it is essential to monitor the internal force state when the bridge is in construction.Among them,how to assess the safety is one of the challenges.As the continuous monitoring over a long-term period can increase the reliability of the assessment,so,based on a large number of monitored strain data collected from the structural health monitoring system(SHMS)during construction,a calculation method of the punctiform time-varying reliability is proposed in this paper to evaluate the stress state of this type bridge in cantilever construction stage by using the basic reliability theory.At the same time,the optimal stress distribution function in the bridge mid-span base plate is determined when the bridge is closed.This method can provide basis and direction for the internal force control of this type bridge in construction process.So,it can reduce the bridge safety and quality accidents in construction stages.
文摘When the bridge components needing maintenance are the world problem at present,and the health monitoring system is considered to be a very helpful tool for solving this problem.In this paper,a large number of strain data acquired from the structural health monitoring system(SHMS)installed on a continuous rigid frame bridge are adopted to do reliability assessment.Firstly,a calculation method of punctiform time-dependent reliability is proposed based on the basic reliability theory,and introduced how to calculate reliability of the bridge by using the stress data transformed from the strain data.Secondly,combined with“Three Sigma”principle and the basic pressure safety reserve requirement,the critical load effects distribution function of the bridge is defined,and then the maintenance reliability threshold for controlling the unfavorable load state which appears in the early operation stage of this type bridge is suggested,and then the combination of bridge maintenance management and health monitoring system is realized.Finally,the transformed stress distribution certifies that the load effects of concrete bridges practically have a normal distribution;as for the concrete continuous rigid frame bridge with C50 strength grade concrete,the retrofit reliability threshold should be valued at 6.13.The methodology suggested in this article can help bridge engineers do effective maintenance of bridges,which can effectively extend the service life of the bridge and bring better economic and social benefits.
基金supported by the Fundamental Research Funds for the Central Universities (N090303005)Key National Science and Technology Special Project (2010ZX04014-014)
文摘With the development of the monitoring technology,it is more and more common that the system is continuously monitored.Therefore,the research on the maintenance optimization of the continuously monitored deterioration system is important.The deterioration process of the discussed system is described by a Gamma process.The predictive maintenance is considered to be imperfect and formulated.The expected interval of two continuous preventive maintenances is derived.Then,the maintenance optimization model of the continuously monitored deterioration system is presented.In the model,the minimization of the expected operational cost per unit time and the maximization of the system availability are the optimization objectives.The improved ideal point method with the normalized objective functions is employed to solve the proposed model.The validity and sensitivity of the proposed multiobjective maintenance optimization model are analyzed by a numerical example.
基金The author N.I.Giannoccaro received funds from the Department of Innovation Engineering,University of Salento,for acquiring the tool Structural Health Monitoring.
文摘The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a goal of extreme and current interest.In the present work,the results obtained from the processing of experimental data of a real structure are shown.The analyzed structure is a lattice structure approximately 9 m high,monitored with 18 uniaxial accelerometers positioned in pairs on 9 different levels.The data used refer to continuous monitoring that lasted for a total of 1 year,during which minor damage was caused to the structure by alternatively removing some bracings and repositioning them in the structure.Two methodologies detecting damage based on decomposition techniques of the acquired data were used and tested,as well as a methodology combining the two techniques.The results obtained are extremely interesting,as all the minor damage caused to the structure was identified by the processing methods used,based solely on the monitored data and without any knowledge of the real structure being analyzed.The results use 15 acquisitions in environmental conditions lasting 10 min each,a reasonable amount of time to get immediate feedback on possible damage to the structure.
基金funded by multidisciplinary MDT diagnosis and treatment fund for glioma and academic discipline boosting of Xijing Hospital.
文摘Background:Awake craniotomy(AC)has become gold standard in surgical resection of gliomas located in eloquent areas.The conscious sedation techniques in AC include both monitored anesthesia care(MAC)and asleep-awake-asleep(AAA).The choice of optimal anesthetic method depends on the preferences of the surgical team(mainly anesthesiologist and neurosurgeon).The aim of this study was to compare the difference in physiological and blood gas data,dosage of different drugs,the probability of switching to endotracheal intubation,and extent of tumor resection and dysfunction after operation between AAA and MAC anesthetic management for resection of gliomas in eloquent brain areas.Methods:Two-hundred and twenty-five patients with super-tentorial tumor located in eloquent areas underwent AC from 2009 to 2021 in Xijing Hospital.Forty-one patients underwent AAA technique,and the rest one-hundred eighty-four patients underwent MAC technique.Anesthetic management,dosage of different drugs,intraoperative complications,postoperative outcomes,adverse events,extent of resection and motor,and sensory and language dysfunction after operation were compared between MAC and AAA.Result:There was no significant difference in gender,KPS score,MMSE score,glioma grade,type,and growth site between the patients in the two groups,except the older age of patients in MAC group than that in AAA group.During the whole process of operation,there were greater pulse pressure difference(P=0.046),shorter operation time(P=0.039),less dosage of remifentanil(P=0.000),more dosage of dexmedetomidine(P=0.013),more use of antiemetics(81%,P=0.0067),lower use of vasoactive agent(45.1%,P=0.010),and lower probability of conversion to general anesthesia(GA,P=0.027)in MAC group than that in AAA group.Blood gas analysis showed that PetCO2(P=0.000),Glu concentration(P=0.000),and PaCO2(P=0.000)were higher,but SPO2(P=0.002)and PaO2(P=0.000)were lower in MAC group than that in AAA group.In the postoperative recovery stage,compared with that of AAA group,the probability of dysfunction in MAC group at 1,3,5,and 7 days after operation was lower,which were 27.8%vs 53.6%(P=0.003),31%vs 68.3%(P=0.000),28.8%vs 63.4%(P=0.000),and 25.6%vs 58.5%(P=0.000),respectively.Conclusion:Compared with AAA,it seems that MAC has more advantages in the management for resection of gliomas in eloquent brain areas,and MAC combined with multiple monitoring such as cerebral cortical mapping,neuronavigation,and ultrasonic detection is worthy of popularization for the resection of gliomas in eloquent brain areas.
基金supported by the Key Technologies Research and Development Program under Grant 2021YFB1600300.
文摘To examine stress redistribution phenomena in bridges subjected to varying operational conditions,this study conducts a comprehensive analysis of three years of monitoring data from a 153-m double-deck road–rail steel arch bridge.An initial statistical comparison of sensor data distributions reveals clear temporal variations in stress redistribution patterns.XGBoost(eXtreme Gradient Boosting),a gradient-boosting machine learning(ML)algorithm,was employed not only for predictive modeling but also to uncover the underlying mechanisms of stress evolution.Unlike traditional numerical models that rely on extensive assumptions and idealizations,XGBoost effectively captures nonlinear and time-varying relationships between stress states and operational/environmental factors,such as temperature,traffic load,and structural geometry.This approach allows for the identification of critical periods and conditions under which stress redistribution becomes significant.Results indicate a clear shift of stress concentrations frombeamends toward mid-span regions following the commencement of metro operations,reflecting both structural adaptation and localized overstress near arch ribs.Furthermore,the model generates robust predictions of stress evolution,demonstrating potential applications in early warning systems and fatigue risk assessment.This work represents the first application of interpretable gradient-boosting techniques to stress redistribution modeling in double-deck bridges.In addition,a Stress Redistribution Index(SRI)is proposed,derived from this monitoring study and finite-element-based transverse load distributions,to quantify temporal stress shifts between midspan and edge beams.The results provide both theoretical contributions and practical guidance for the design,inspection,and maintenance of complex bridge structures.
基金funded by Princess Nourah bint Abdulrahman University Researchers Support-ing Project number(PNURSP2026R346)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Motor imbalance is a critical failure mode in rotating machinery,potentially causing severe equipment damage if undetected.Traditional vibration-based diagnostic methods rely on direct sensor contact,leading to installation challenges and measurement artifacts that can compromise accuracy.This study presents a novel radar-based framework for non-contact motor imbalance detection using 24 GHz continuous-wave radar.A dataset of 1802 experimental trials was sourced,covering four imbalance levels(0,10,20,30 g)across varying motor speeds(500–1500 rpm)and load torques(0–3 Nm).Dual-channel in-phase and quadrature radar signals were captured at 10,000 samples per second for 30-s intervals,preserving both amplitude and phase information for analysis.A multi-domain feature extraction methodology captured imbalance signatures in time,frequency,and complex signal domains.From 65 initial features,statistical analysis using Kruskal–Wallis tests identified significant descriptors,and recursive feature elimination with Random Forest reduced the feature set to 20 dimensions,achieving 69%dimensionality reduction without loss of performance.Six machine learning algorithms,Random Forest,Extra Trees Classifier,Extreme Gradient Boosting,Categorical Boosting,Support Vector Machine with radial basis function kernel,and k-Nearest Neighbors were evaluated with grid-search hyperparameter optimization and five-fold cross-validation.The Extra Trees Classifier achieved the best performance with 98.52%test accuracy,98%cross-validation accuracy,and minimal variance,maintaining per-class precision and recall above 97%.Its superior performance is attributed to its randomized split selection and full bootstrapping strategy,which reduce variance and overfitting while effectively capturing the nonlinear feature interactions and non-normal distributions present in the dataset.The model’s average inference time of 70 ms enables near real-time deployment.Comparative analysis demonstrates that the radar-based framework matches or exceeds traditional contact-based methods while eliminating their inherent limitations,providing a robust,scalable,and noninvasive solution for industrial motor condition monitoring,particularly in hazardous or space-constrained environments.
基金support of the National Natural Science Foundation of China(No.52274176)the Guangdong Province Key Areas R&D Program(No.2022B0101070001)+5 种基金Chongqing Elite Innovation and Entrepreneurship Leading talent Project(No.CQYC20220302517)the Chongqing Natural Science Foundation Innovation and Development Joint Fund(No.CSTB2022NSCQ-LZX0079)the National Key Research and Development Program Young Scientists Project(No.2022YFC2905700)the Chongqing Municipal Education Commission“Shuangcheng Economic Circle Construction in Chengdu-Chongqing Area”Science and Technology Innovation Project(No.KJCX2020031)the Fundamental Research Funds for the Central Universities(No.2024CDJGF-009)the Key Project for Technological Innovation and Application Development in Chongqing(No.CSTB2025TIAD-KPX0029).
文摘An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.
