The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a rese...The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a research hotspot in the industry. This paper proposes a position and attitude calibration method with error correction based on the combination of the feature point and feature surface. First, the initial value of the spatial position relation-ship between each sensor of MMS is obtained by close-range photogrammetry. Second, the optimal solution for error correction is calculated by feature points in global coordinates jointly measured with International GNSS Service (IGS) stations. Then, the final transformation para-meters are solved by combining the initial values obtained originally, thereby realizing the rapid calibration of the MMS. Finally, it analyzed the RMSE of MMS point cloud after calibration, and the results demonstrate the feasibility of the calibration approach proposed by this method. Under the condition of a single measurement sensor accuracy is low, the plane and elevation absolute accuracy of the point cloud after calibration can reach 0.043 m and 0.072 m, respectively, and the relative accuracy is smaller than 0.02 m. It meets the precision require-ments of data acquisition for MMS. It is of great significance for promoting the development of MMS technology and the application of some novel techniques in the future, such as auton-omous driving, digital twin city, urban brain et al.展开更多
In this paper a label-based simultaneous localization and mapping（ SLAM） system is proposed to provide localization to indoor autonomous robots. In the system quick response（ QR） codes encoded with serial numbers ...In this paper a label-based simultaneous localization and mapping（ SLAM） system is proposed to provide localization to indoor autonomous robots. In the system quick response（ QR） codes encoded with serial numbers are utilized as labels. These labels are captured by two webcams,then the distances and angles between the labels and webcams are computed. Motion estimated from the two rear wheel encoders is adjusted by observing QR codes. Our system uses the extended Kalman filter（ EKF） for the back-end state estimation. The number of deployed labels controls the state estimation dimension. The label-based EKF-SLAM system eliminates complicated processes,such as data association and loop closure detection in traditional feature-based visual SLAM systems. Our experiments include software-simulation and robot-platform test in a real environment. Results demonstrate that the system has the capability of correcting accumulated errors of dead reckoning and therefore has the advantage of superior precision.展开更多
Objective:In this study, the feasibility to evaluate the global myocardial activation and repolarization sequence using the electroanatomical mapping system and MAP recording technique via the modified platinum cathet...Objective:In this study, the feasibility to evaluate the global myocardial activation and repolarization sequence using the electroanatomical mapping system and MAP recording technique via the modified platinum catheter was explored in swine. Methods:Ten healthy pigs (50-55 kg) were anaesthetized with pentobarbital and catamine, intubated and ventilated. Four vascular accesses were obtained. A modified small tip ablation catheter (Navi-Star, Biosense Webster), the end surface of tip electrode was 0.81 mm 2 and 1 mm in diameter, was used for MAP recording. The MAP electrograms were recorded between the tip (exploring electrode) and the ring electrode proximal to the tip (indifferent electrode). The catheter was intentionally positioned perpendicular to endocardium with slight contact pressure to allow MAP recording with a satisfactory amplitude and morphology. All MAP recordings were performed during sinus rhythm.Results:The MAP recordings were obtained from both right atrium and left ventricle in 9 pigs, while the right ventricle was mapped during the same procedure in 2. The MAP electrograms were recorded from both right and left atrium via a patent foramen ovale in 1 pig. Totally, the right atrium was mapped in all the 10 pigs, right ventricle in 2, left atrium in 1 and left ventricle in 9. The MAP electrograms were recorded from 733 sites of right atrium, 179 of right ventricle, 63 of left atrium and 517 of left ventricle. There were 62% of right and 54% left atrial MAPamp satisfied the earlier defined criteria of acceptable MAP, i.e., the MAPamp ≥ 3 mV in atrium, while 32% of right and 38% of left ventricular MAPamp were ≥ 10 mV. The mean MAPamp was 5.7±3.1 mV in right atrium, 12.4±2.5 mV in right ventricle, 4.5±1.9 mV in left atrium and 13.8±4 mV in left ventricle. The local activation was more distinctly and easily defined using MAP recordings with the computer-assisted manual determination, so were the end-of-repolarization points. The global activation and repolarization sequence and MAP duration distribution were constructed in all the pigs both in atrium and in ventricle. The activation sequence both in atrium and ventricle could be determined in all pigs three-dimensionally. In the right atrium two preferential inter-nodal conductions were evident, along the crista terminalis and atrial septum from the sinus node area down to the atrioventricular node. Two main connections, Bachman’s bundle and coronary sinus region, constitute the electrophysiologic pathways for right to left atria activation during sinus rhythm. The earliest ventricular activation was located at the high left ventricular septum and followed by radial activation sequence in both ventricles. The posterior base segments of left and right ventricle were activated latest. In the 4 pigs whose chest was opened after sacrifice, no visual detectable injury or bleeding was found in the endocardium and valvular structure. No perforation and no epicardial effusion were observed either.Conclusion: MAP electrograms recorded using the modified platinum catheter were associated with a stable baseline and higher amplitude. MAP recording in difficult areas in all the four chambers of the swine heart was facilitated by the modification of the tip electrode. The construction of the global myocardial activation and repolarization sequence is feasible using the electroanatomical mapping system and MAP recording technique via the modified catheter. The ability to combine MAP recording and spatial information provides a unique tool for both research and clinical electrophysiology.展开更多
In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camer...In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camera motion of two consecutive RGB-D frames by minimizing the photometric error.To permit outliers and noise,a robust sensor model built upon the t-distribution and an error function mixing depth and photometric errors are used to enhance the accuracy and robustness.Local graph optimization based on key frames is used to reduce the accumulative error and refine the local map.The loop closure detection method,which combines the appearance similarity method and spatial location constraints method,increases the speed of detection.Experimental results demonstrate that the proposed approach achieves higher accuracy on the motion estimation and environment reconstruction compared to the other state-of-the-art methods. Moreover,the proposed approach works in real-time on a laptop without a GPU,which makes it attractive for robots equipped with limited computational resources.展开更多
In the paper researches on a three-dimensional measure-preserving mappingsystem are made,which is the three-dimensional extension of the Keplerian mapping.With formal series method the expressions of the invariant cur...In the paper researches on a three-dimensional measure-preserving mappingsystem are made,which is the three-dimensional extension of the Keplerian mapping.With formal series method the expressions of the invariant curves and invarianttori are obtained,Finally the stability of these in variant manifolds is also discussed.展开更多
Multi-object tracking is a vital problem as many applications require better tracking approaches.Although learning-based detectors are becoming extremely powerful,there are few tracking methods designed to work with t...Multi-object tracking is a vital problem as many applications require better tracking approaches.Although learning-based detectors are becoming extremely powerful,there are few tracking methods designed to work with them in real time.We explored an efficient flexible online vehicle tracking-by-detection framework suitable for real-virtual mapping systems,which combines a non-recursive temporal window search with delayed output and produces stable trajectories despite noisy detection responses.Its computation speed meets the real-time requirements,whereas its performance is comparable with that of state-of-the-art online trackers on the DETRAC dataset.The trajectories from our approach also contain the target class and color information important for virtual vehicle motion reconstruction.展开更多
A low-frequency magnetic lightning mapping system(LFM-LMS)was built during the SHAndong Triggered Lightning Experiment(SHATLE),based on continuous measurements of magnetic field radiation from lightning.The hardware a...A low-frequency magnetic lightning mapping system(LFM-LMS)was built during the SHAndong Triggered Lightning Experiment(SHATLE),based on continuous measurements of magnetic field radiation from lightning.The hardware and source-mapping techniques used by the LFM-LMS were introduced;both Monte Carlo simulations and the observation of rocket-triggered lightning examples were employed to examine the location accuracy and detection effectiveness of the LFM-LMS.We estimated that the system’s location accuracy about 100−200 m horizontally and~200 m vertically.A natural intra-cloud lightning flash and a rocket-triggered lightning flash,both with intricate structures and discharging processes,were examined using the three-dimensional mapping results.The progressing path of negative lightning leaders is usually well-defined,and its propagation speed is estimated to be(0.5−1.4)×10^(6)m/s.In summary,the LFM-LMS can reconstruct the three-dimensional morphology of lightning flashes;this technology provides a efficient method for investigating the characteristics of lightning development,as well as the overall electrical strucuture of thunderstorms.展开更多
The original surveying tools and methods are backward and low efficient and they will also generate lots of errors in the National secondary land surveying. MapSUV rural land surveying palm mapping system (MapSUV palm...The original surveying tools and methods are backward and low efficient and they will also generate lots of errors in the National secondary land surveying. MapSUV rural land surveying palm mapping system (MapSUV palm mapping system) based on 3S techniques, combines MapGIS rural land surveying database management system. It supports the spatial location information collection and attributes data entry. By combining with GPS receiver, it ensures high accuracy in small volume, which greatly facilitates land surveying. This paper main researched system structure, function module design and key techniques. It introduced the practical process of map spot attribute checking and map spot boundary. Then it gave the application assessment. The results shows that this system greatly improves the work efficiency of outdoor surveying and shorten the time of land surveying, database build and updating.展开更多
The micro-beam is a beam of micrometer or sub-micrometer dimension, which allows precise defined quantitiesof ions to be introduced at precisely defined location. It has been a powerful tool for single event effects (...The micro-beam is a beam of micrometer or sub-micrometer dimension, which allows precise defined quantitiesof ions to be introduced at precisely defined location. It has been a powerful tool for single event effects (SEE)study. At the IMP micro-beam facility, we have preliminarily built a SEE mapping system to study the microscopicsensitive areas of SEEs on integrated chips.In order to map the SEE distribution with the ion irradiation, the SEE event signal (E) from the device undertest is detected by the analog input of the SEE mapping system; through the SEE mapping software control, thebeam is scanned with the magnetic scan coil of the microbeam facility and the beam position of the scan coil ofthe microbeam facility is used to register the SEE position (X, Y ); Finally, the SEE distribution is drew with apseudo-color bit image online using (NE, X, Y ), where NE is the number of occurrence of SEE type E at beamposition (X, Y ). The input of the SEE mapping system can support simultaneously detection of up to three SEEsignals.展开更多
Objective:Few studies have been conducted to establish animal models of left bundle branch block by using three-dimensional mapping systems.This research was aimed at creating a canine left bundle branch block model b...Objective:Few studies have been conducted to establish animal models of left bundle branch block by using three-dimensional mapping systems.This research was aimed at creating a canine left bundle branch block model by using a three-dimensional mapping system.Materials and Methods:We used a three-dimensional mapping system to map and ablate the left bundle branch in beagles.Results:Ten canines underwent radiofrequency ablation,among which left bundle branch block was successfully es-tablished in eight,one experienced ventricular fibrillation,and one developed third-degree atrioventricular block.The maximum HV interval measured within the left ventricle was 29.00±2.93 ms,and the LBP-V interval at the ablation site was 20.63±2.77 ms.The LBP-V interval at the ablation target was 71.08%of the maximum HV interval.Conclusion:This three-dimensional mapping system is a reliable and effective guide for ablation of the left bundle branch in dogs.展开更多
Bioclimatic classification(WBCS),which examines the relationship between vegetation distribution and climatic variables such as precipitation and temperature,is essential for understanding the ecological dynamics.This...Bioclimatic classification(WBCS),which examines the relationship between vegetation distribution and climatic variables such as precipitation and temperature,is essential for understanding the ecological dynamics.This research focuses on producing a detailed bioclimatic map of Oaxaca,Mexico,at a spatial resolution of 30 arc-seconds,using the methodology developed by Rivas-Martínez et al.(2011).Oaxaca,characterised by its complex topography and diverse climatic conditions,provides a unique opportunity to study bioclimatic patterns in a tropical region.Using high-resolution climate data from Chelsa database,we identified and mapped different bioclimates,variants,thermotypes and ombrotypes horizons and levels of continentality within the tropical macrobioclimate.Our analysis revealed a rich diversity of bioclimatic zones,reflecting the complex interplay between Oaxaca's physical geography and its bioclimates.The results,presented in high resolution maps,highlight the spatial variability and complexity of Oaxaca's bioclimatic landscape.These findings are crucial for several applications,including biodiversity conservation,agricultural planning and climate change adaptation strategies.By providing an accurate bioclimatic classification,this study makes a significant contribution to bioclimatology and could give valuable insights into climate-vegetation relationships in tropical regions.This detailed bioclimatic map improves our understanding of the current ecological status of Oaxaca and serves as a critical tool for future environmental planning and conservation efforts.Furthermore,it could be the basis for planning in national programs that consider agriculture and forests in Mexico such as Programa Sembrando Vida(PSV).展开更多
Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)feat...Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)featured chromophore(HBT-DPI)that shows flexible emission tunability via the multidimensional regulation of intra-and intermolecular H-bonds.The feature of switchable intramolecular Hbonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule,allowing the“turn on/off”of ESIPT process by forming isomers with distinct intramolecular Hbonds configurations.In response to different external H-bonding environments,the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes,which are mainly guided by the intermolecular H-bonds,exhibiting non-emissive features or emissions ranging from green to orange.Utilizing the feature of intermolecular H-bond guided molecular packing,we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene)(PVDF)membranes and quantitatively estimating the surface hydrophobicity,providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement.Overall,this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications.展开更多
After the fabrication of magnetic resonance superconducting magnets,the magnetic field inhomogeneity needs to be accurately measured for subsequent shimming.However,conventional measurement methods are susceptible to ...After the fabrication of magnetic resonance superconducting magnets,the magnetic field inhomogeneity needs to be accurately measured for subsequent shimming.However,conventional measurement methods are susceptible to magnetic fields,have poor compatibility,and are difficult to adapt to various types of magnets.This paper proposes a new field measuring system based on a three-axis movable platform.The system utilizes non-magnetic materials and an innovative hand-wheel lifting design that can be adapted to various aperture magnets,thus obviating the necessity for electrically driven equipment and addressing safety concerns in strong magnetic fields.In addition,the measurement system offers high accuracy up to 1 mm and a wide measurable range.The fields of 3 T and 7 T magnets were mapped using the designed system with diameter of spherical volume(DSV)of 160 mm and 130 mm,respectively.Experimental results demonstrate that the magnetic field measurement system has strong compatibility and can accurately map the magnetic field at arbitrary positions,which is critical for shimming studies.展开更多
Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultiv...Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultivation management and promoting the sustainable development of the cotton industry.Xinjiang is the primary cotton-producing region in China.However,long-term data of cotton cultiv-ation areas with high spatial resolution are unavailable for Xinjiang,China.Therefore,this study aimed to identify and map an accurate 30-m cotton cultivation area dataset in Xinjiang from 2000 to 2020 by applying a Random Forest(RF)-based method that integrates Landsat and Moderate Resolution Imaging Spectroradiometer(MODIS)images,and validated the applicability and accuracy of dataset at a large spatial scale.Then,this study analyzed the spatiotemporal variations and influencing factors of cotton cultivation in the study period.The results showed that a high classification accuracy was achieved(overall accuracy>85%,F1>0.80),strongly agreeing with county-level agricultural statistical yearbook data(R2>0.72).Significant spatiotemporal variation in the cotton cultivation areas was found in Xinjiang,with a total increase of 1131.26 kha from 2000 to 2020.Notably,cotton cultivation area in southern Xinjiang expan-ded substantially,with that in Aksu increasing from 20.10%in 2000 to 28.17%in 2020,representing an expansion of 374.29 kha.In northern Xinjiang,the cotton areas in the Tacheng region also exhibited significant increased by almost ten percentage points in the same period.In contrast,cotton cultivation in eastern Xinjiang declined,decreasing from 2.22%in 2000 to merely 0.24%in 2020.Standard deviation ellipse analysis revealed a‘northeast-southwest’spatial distribution,with the centroid consistently located in Aksu and shifting 102.96 km over the 20-yr period.Pearson correlation analysis indicated that socioeconomic factors had a stronger influence on cotton cultivation than climatic factors,with effective irrigation area(r=0.963,P<0.05)and total agricultural machinery power(r=0.823)showing significant positive correlations,whereas climatic variables exhibiting weak associations(r<0.200).These results provide valuable scientific data for informed agricultural management,sustainable development,and policymaking.展开更多
Objective To describe a new noncontact balloon catheter mapping system and to assess the clinical utility of this system for guiding endocardial mapping and ablation of tachycardia.Methods Five patients with tachycard...Objective To describe a new noncontact balloon catheter mapping system and to assess the clinical utility of this system for guiding endocardial mapping and ablation of tachycardia.Methods Five patients with tachycardia underwent endocardial mapping and radiofrequency ablation using the noncontact balloon catheter mapping system. A 9 French, 64-electrode balloon catheter and a conventional 7 French electrode catheter for mapping and ablation were positioned in the same ventricular chamber. Ventricular three-dimensional geometry was established by the computerized mapping system. Using a boundary element inverse solution, 3360 virtual endocardial electrograms were computerized and used to derive isopotential maps. The earliest endocardial activation site, the exit site and the activation sequence of tachycardia or the critical isthmus of the reentry circuit were identified. Radiofrequency ablation with circular or linear lesion was performed at the target sites guided by the locator system.Results Six clinical types of tachycardia, 5 of which were ventricular tachycardia and one was concealed fasciculoventricular fiber mediated tachycardia, were induced by programmed stimulation. The mean cycle length of these tachycardias was 336.6±42.69 msec. The earliest activation site and the exit site of 5 mapped tachycardias were all identified using the system. One type of ventricular tachycardia was hemodynamically unstable and difficult to terminate, and could not be mapped. Among the 6 types of tachycardias, radiofrequency ablation was successful in 4. There was no complication during and after the procedure. During the mean follow-up of 6 months, no tachycardia recurred in the patients with a successful ablation.Conclusions The noncontact mapping system described in this study has advantage over conventional mapping techniques for refractory tachycardia. It is not only helpful for understanding the electrophysiologic mechanism of a complex case, but also suitable for mapping hemodynamically-intolerated and nonsustained ventricular tachycardia.展开更多
Among the major natural disasters that occurred in 2010,the Haiti earthquake was a real turning point concerning the availability,dissemination and licensing of a huge quantity of geospatial data.In a few days several...Among the major natural disasters that occurred in 2010,the Haiti earthquake was a real turning point concerning the availability,dissemination and licensing of a huge quantity of geospatial data.In a few days several map products based on the analysis of remotely sensed data-sets were delivered to users.This demonstrated the need for reliable methods to validate the increasing variety of open source data and remote sensing-derived products for crisis management,with the aim to correctly spatially reference and interconnect these data with other global digital archives.As far as building damage assessment is concerned,the need for accurate field data to overcome the limitations of both vertical and oblique view satellite and aerial images was evident.To cope with the aforementioned need,a newly developed Low-Cost Mobile Mapping System(LCMMS)was deployed in Port-au-Prince(Haiti)and tested during a five-day survey in FebruaryMarch 2010.The system allows for acquisition of movies and single georeferenced frames by means of a transportable device easily installable(or adaptable)to every type of vehicle.It is composed of four webcams with a total field of view of about 180 degrees and one Global Positioning System(GPS)receiver,with the main aim to rapidly cover large areas for effective usage in emergency situations.The main technical features of the LCMMS,the operational use in the field(and related issues)and a potential approach to be adopted for the validation of satellite/aerial building damage assessments are thoroughly described in the article.展开更多
基金This research was funded by the National Natural Science Foundation of China[grant number 41971350 and 41571437]Beijing Advanced Innovation Centre for Future Urban Design Project[grant number UDC2019031724]+4 种基金Teacher Support Program for Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture[grant number JDJQ20200307]State Key Laboratory of Geo-Information Engineering[grant number SKLGIE2019-Z-3-1]Open Research Fund Program of LIESMARS[grant number 19E01]National Key Research and Development Program of China[grant number 2019YFC1520100]The Fundamental Research Funds for Beijing University of Civil Engineering and Architecture[grant number X18050].
文摘The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a research hotspot in the industry. This paper proposes a position and attitude calibration method with error correction based on the combination of the feature point and feature surface. First, the initial value of the spatial position relation-ship between each sensor of MMS is obtained by close-range photogrammetry. Second, the optimal solution for error correction is calculated by feature points in global coordinates jointly measured with International GNSS Service (IGS) stations. Then, the final transformation para-meters are solved by combining the initial values obtained originally, thereby realizing the rapid calibration of the MMS. Finally, it analyzed the RMSE of MMS point cloud after calibration, and the results demonstrate the feasibility of the calibration approach proposed by this method. Under the condition of a single measurement sensor accuracy is low, the plane and elevation absolute accuracy of the point cloud after calibration can reach 0.043 m and 0.072 m, respectively, and the relative accuracy is smaller than 0.02 m. It meets the precision require-ments of data acquisition for MMS. It is of great significance for promoting the development of MMS technology and the application of some novel techniques in the future, such as auton-omous driving, digital twin city, urban brain et al.
基金Supported by Program for Changjiang Scholars and Innovative Research Team in University,National Science Foundation of China(61105092)the National Natural Science Foundation of China(61473042)
文摘In this paper a label-based simultaneous localization and mapping（ SLAM） system is proposed to provide localization to indoor autonomous robots. In the system quick response（ QR） codes encoded with serial numbers are utilized as labels. These labels are captured by two webcams,then the distances and angles between the labels and webcams are computed. Motion estimated from the two rear wheel encoders is adjusted by observing QR codes. Our system uses the extended Kalman filter（ EKF） for the back-end state estimation. The number of deployed labels controls the state estimation dimension. The label-based EKF-SLAM system eliminates complicated processes,such as data association and loop closure detection in traditional feature-based visual SLAM systems. Our experiments include software-simulation and robot-platform test in a real environment. Results demonstrate that the system has the capability of correcting accumulated errors of dead reckoning and therefore has the advantage of superior precision.
文摘Objective:In this study, the feasibility to evaluate the global myocardial activation and repolarization sequence using the electroanatomical mapping system and MAP recording technique via the modified platinum catheter was explored in swine. Methods:Ten healthy pigs (50-55 kg) were anaesthetized with pentobarbital and catamine, intubated and ventilated. Four vascular accesses were obtained. A modified small tip ablation catheter (Navi-Star, Biosense Webster), the end surface of tip electrode was 0.81 mm 2 and 1 mm in diameter, was used for MAP recording. The MAP electrograms were recorded between the tip (exploring electrode) and the ring electrode proximal to the tip (indifferent electrode). The catheter was intentionally positioned perpendicular to endocardium with slight contact pressure to allow MAP recording with a satisfactory amplitude and morphology. All MAP recordings were performed during sinus rhythm.Results:The MAP recordings were obtained from both right atrium and left ventricle in 9 pigs, while the right ventricle was mapped during the same procedure in 2. The MAP electrograms were recorded from both right and left atrium via a patent foramen ovale in 1 pig. Totally, the right atrium was mapped in all the 10 pigs, right ventricle in 2, left atrium in 1 and left ventricle in 9. The MAP electrograms were recorded from 733 sites of right atrium, 179 of right ventricle, 63 of left atrium and 517 of left ventricle. There were 62% of right and 54% left atrial MAPamp satisfied the earlier defined criteria of acceptable MAP, i.e., the MAPamp ≥ 3 mV in atrium, while 32% of right and 38% of left ventricular MAPamp were ≥ 10 mV. The mean MAPamp was 5.7±3.1 mV in right atrium, 12.4±2.5 mV in right ventricle, 4.5±1.9 mV in left atrium and 13.8±4 mV in left ventricle. The local activation was more distinctly and easily defined using MAP recordings with the computer-assisted manual determination, so were the end-of-repolarization points. The global activation and repolarization sequence and MAP duration distribution were constructed in all the pigs both in atrium and in ventricle. The activation sequence both in atrium and ventricle could be determined in all pigs three-dimensionally. In the right atrium two preferential inter-nodal conductions were evident, along the crista terminalis and atrial septum from the sinus node area down to the atrioventricular node. Two main connections, Bachman’s bundle and coronary sinus region, constitute the electrophysiologic pathways for right to left atria activation during sinus rhythm. The earliest ventricular activation was located at the high left ventricular septum and followed by radial activation sequence in both ventricles. The posterior base segments of left and right ventricle were activated latest. In the 4 pigs whose chest was opened after sacrifice, no visual detectable injury or bleeding was found in the endocardium and valvular structure. No perforation and no epicardial effusion were observed either.Conclusion: MAP electrograms recorded using the modified platinum catheter were associated with a stable baseline and higher amplitude. MAP recording in difficult areas in all the four chambers of the swine heart was facilitated by the modification of the tip electrode. The construction of the global myocardial activation and repolarization sequence is feasible using the electroanatomical mapping system and MAP recording technique via the modified catheter. The ability to combine MAP recording and spatial information provides a unique tool for both research and clinical electrophysiology.
基金Supported by the National Natural Science Foundation of China(61501034)
文摘In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camera motion of two consecutive RGB-D frames by minimizing the photometric error.To permit outliers and noise,a robust sensor model built upon the t-distribution and an error function mixing depth and photometric errors are used to enhance the accuracy and robustness.Local graph optimization based on key frames is used to reduce the accumulative error and refine the local map.The loop closure detection method,which combines the appearance similarity method and spatial location constraints method,increases the speed of detection.Experimental results demonstrate that the proposed approach achieves higher accuracy on the motion estimation and environment reconstruction compared to the other state-of-the-art methods. Moreover,the proposed approach works in real-time on a laptop without a GPU,which makes it attractive for robots equipped with limited computational resources.
文摘In the paper researches on a three-dimensional measure-preserving mappingsystem are made,which is the three-dimensional extension of the Keplerian mapping.With formal series method the expressions of the invariant curves and invarianttori are obtained,Finally the stability of these in variant manifolds is also discussed.
文摘Multi-object tracking is a vital problem as many applications require better tracking approaches.Although learning-based detectors are becoming extremely powerful,there are few tracking methods designed to work with them in real time.We explored an efficient flexible online vehicle tracking-by-detection framework suitable for real-virtual mapping systems,which combines a non-recursive temporal window search with delayed output and produces stable trajectories despite noisy detection responses.Its computation speed meets the real-time requirements,whereas its performance is comparable with that of state-of-the-art online trackers on the DETRAC dataset.The trajectories from our approach also contain the target class and color information important for virtual vehicle motion reconstruction.
基金the National Key R&D Program of China(2017YFC1501501)the CAS Project of Stable Support for Youth Team in Basic Research Field(YSRR-018)+3 种基金the Youth Innovation Fund project of the university(WK2080000172)the National Natural Science Foundation of China(41875006,U1938115)the Chinese Meridian Projectthe International Partnership Program of Chinese Academy of Sciences(183311KYSB20200003).
文摘A low-frequency magnetic lightning mapping system(LFM-LMS)was built during the SHAndong Triggered Lightning Experiment(SHATLE),based on continuous measurements of magnetic field radiation from lightning.The hardware and source-mapping techniques used by the LFM-LMS were introduced;both Monte Carlo simulations and the observation of rocket-triggered lightning examples were employed to examine the location accuracy and detection effectiveness of the LFM-LMS.We estimated that the system’s location accuracy about 100−200 m horizontally and~200 m vertically.A natural intra-cloud lightning flash and a rocket-triggered lightning flash,both with intricate structures and discharging processes,were examined using the three-dimensional mapping results.The progressing path of negative lightning leaders is usually well-defined,and its propagation speed is estimated to be(0.5−1.4)×10^(6)m/s.In summary,the LFM-LMS can reconstruct the three-dimensional morphology of lightning flashes;this technology provides a efficient method for investigating the characteristics of lightning development,as well as the overall electrical strucuture of thunderstorms.
文摘The original surveying tools and methods are backward and low efficient and they will also generate lots of errors in the National secondary land surveying. MapSUV rural land surveying palm mapping system (MapSUV palm mapping system) based on 3S techniques, combines MapGIS rural land surveying database management system. It supports the spatial location information collection and attributes data entry. By combining with GPS receiver, it ensures high accuracy in small volume, which greatly facilitates land surveying. This paper main researched system structure, function module design and key techniques. It introduced the practical process of map spot attribute checking and map spot boundary. Then it gave the application assessment. The results shows that this system greatly improves the work efficiency of outdoor surveying and shorten the time of land surveying, database build and updating.
文摘The micro-beam is a beam of micrometer or sub-micrometer dimension, which allows precise defined quantitiesof ions to be introduced at precisely defined location. It has been a powerful tool for single event effects (SEE)study. At the IMP micro-beam facility, we have preliminarily built a SEE mapping system to study the microscopicsensitive areas of SEEs on integrated chips.In order to map the SEE distribution with the ion irradiation, the SEE event signal (E) from the device undertest is detected by the analog input of the SEE mapping system; through the SEE mapping software control, thebeam is scanned with the magnetic scan coil of the microbeam facility and the beam position of the scan coil ofthe microbeam facility is used to register the SEE position (X, Y ); Finally, the SEE distribution is drew with apseudo-color bit image online using (NE, X, Y ), where NE is the number of occurrence of SEE type E at beamposition (X, Y ). The input of the SEE mapping system can support simultaneously detection of up to three SEEsignals.
基金This work was supported by the National Science Foundation for Young Researchers of China(grant Nos:82000315,82000325 and 82100325).
文摘Objective:Few studies have been conducted to establish animal models of left bundle branch block by using three-dimensional mapping systems.This research was aimed at creating a canine left bundle branch block model by using a three-dimensional mapping system.Materials and Methods:We used a three-dimensional mapping system to map and ablate the left bundle branch in beagles.Results:Ten canines underwent radiofrequency ablation,among which left bundle branch block was successfully es-tablished in eight,one experienced ventricular fibrillation,and one developed third-degree atrioventricular block.The maximum HV interval measured within the left ventricle was 29.00±2.93 ms,and the LBP-V interval at the ablation site was 20.63±2.77 ms.The LBP-V interval at the ablation target was 71.08%of the maximum HV interval.Conclusion:This three-dimensional mapping system is a reliable and effective guide for ablation of the left bundle branch in dogs.
基金support is acknowledged from Universidad Nacional Autónoma de México Project:DGAPA-PAPIIT IN105721,Project IN229325 DGAPAUNAM and Posdoc scholarship for Alejandro González-Pérez(UNAM-DGAPA Postdoctoral Program).
文摘Bioclimatic classification(WBCS),which examines the relationship between vegetation distribution and climatic variables such as precipitation and temperature,is essential for understanding the ecological dynamics.This research focuses on producing a detailed bioclimatic map of Oaxaca,Mexico,at a spatial resolution of 30 arc-seconds,using the methodology developed by Rivas-Martínez et al.(2011).Oaxaca,characterised by its complex topography and diverse climatic conditions,provides a unique opportunity to study bioclimatic patterns in a tropical region.Using high-resolution climate data from Chelsa database,we identified and mapped different bioclimates,variants,thermotypes and ombrotypes horizons and levels of continentality within the tropical macrobioclimate.Our analysis revealed a rich diversity of bioclimatic zones,reflecting the complex interplay between Oaxaca's physical geography and its bioclimates.The results,presented in high resolution maps,highlight the spatial variability and complexity of Oaxaca's bioclimatic landscape.These findings are crucial for several applications,including biodiversity conservation,agricultural planning and climate change adaptation strategies.By providing an accurate bioclimatic classification,this study makes a significant contribution to bioclimatology and could give valuable insights into climate-vegetation relationships in tropical regions.This detailed bioclimatic map improves our understanding of the current ecological status of Oaxaca and serves as a critical tool for future environmental planning and conservation efforts.Furthermore,it could be the basis for planning in national programs that consider agriculture and forests in Mexico such as Programa Sembrando Vida(PSV).
基金supported by the National Key R&D Program of China(No.2021YFC2103600)the National Natural Science Foundation of China(Nos.21878156,21978131,22275085,and 22278224)+2 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20200089 and BK20200691)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the State Key Laboratory of Materials-Oriented Chemical Engineering(No.KL21-08).
文摘Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)featured chromophore(HBT-DPI)that shows flexible emission tunability via the multidimensional regulation of intra-and intermolecular H-bonds.The feature of switchable intramolecular Hbonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule,allowing the“turn on/off”of ESIPT process by forming isomers with distinct intramolecular Hbonds configurations.In response to different external H-bonding environments,the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes,which are mainly guided by the intermolecular H-bonds,exhibiting non-emissive features or emissions ranging from green to orange.Utilizing the feature of intermolecular H-bond guided molecular packing,we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene)(PVDF)membranes and quantitatively estimating the surface hydrophobicity,providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement.Overall,this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications.
基金supported by the National Science Foundation of China(Grant No.52293423 and Grant No.52277031).
文摘After the fabrication of magnetic resonance superconducting magnets,the magnetic field inhomogeneity needs to be accurately measured for subsequent shimming.However,conventional measurement methods are susceptible to magnetic fields,have poor compatibility,and are difficult to adapt to various types of magnets.This paper proposes a new field measuring system based on a three-axis movable platform.The system utilizes non-magnetic materials and an innovative hand-wheel lifting design that can be adapted to various aperture magnets,thus obviating the necessity for electrically driven equipment and addressing safety concerns in strong magnetic fields.In addition,the measurement system offers high accuracy up to 1 mm and a wide measurable range.The fields of 3 T and 7 T magnets were mapped using the designed system with diameter of spherical volume(DSV)of 160 mm and 130 mm,respectively.Experimental results demonstrate that the magnetic field measurement system has strong compatibility and can accurately map the magnetic field at arbitrary positions,which is critical for shimming studies.
基金Under the auspices of the National Natural Science Foundation of China(No.42101342,U2243205)the Third Comprehensive Scientific Expedition to Xinjiang(No.2021XJKK1403)。
文摘Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultivation management and promoting the sustainable development of the cotton industry.Xinjiang is the primary cotton-producing region in China.However,long-term data of cotton cultiv-ation areas with high spatial resolution are unavailable for Xinjiang,China.Therefore,this study aimed to identify and map an accurate 30-m cotton cultivation area dataset in Xinjiang from 2000 to 2020 by applying a Random Forest(RF)-based method that integrates Landsat and Moderate Resolution Imaging Spectroradiometer(MODIS)images,and validated the applicability and accuracy of dataset at a large spatial scale.Then,this study analyzed the spatiotemporal variations and influencing factors of cotton cultivation in the study period.The results showed that a high classification accuracy was achieved(overall accuracy>85%,F1>0.80),strongly agreeing with county-level agricultural statistical yearbook data(R2>0.72).Significant spatiotemporal variation in the cotton cultivation areas was found in Xinjiang,with a total increase of 1131.26 kha from 2000 to 2020.Notably,cotton cultivation area in southern Xinjiang expan-ded substantially,with that in Aksu increasing from 20.10%in 2000 to 28.17%in 2020,representing an expansion of 374.29 kha.In northern Xinjiang,the cotton areas in the Tacheng region also exhibited significant increased by almost ten percentage points in the same period.In contrast,cotton cultivation in eastern Xinjiang declined,decreasing from 2.22%in 2000 to merely 0.24%in 2020.Standard deviation ellipse analysis revealed a‘northeast-southwest’spatial distribution,with the centroid consistently located in Aksu and shifting 102.96 km over the 20-yr period.Pearson correlation analysis indicated that socioeconomic factors had a stronger influence on cotton cultivation than climatic factors,with effective irrigation area(r=0.963,P<0.05)and total agricultural machinery power(r=0.823)showing significant positive correlations,whereas climatic variables exhibiting weak associations(r<0.200).These results provide valuable scientific data for informed agricultural management,sustainable development,and policymaking.
文摘Objective To describe a new noncontact balloon catheter mapping system and to assess the clinical utility of this system for guiding endocardial mapping and ablation of tachycardia.Methods Five patients with tachycardia underwent endocardial mapping and radiofrequency ablation using the noncontact balloon catheter mapping system. A 9 French, 64-electrode balloon catheter and a conventional 7 French electrode catheter for mapping and ablation were positioned in the same ventricular chamber. Ventricular three-dimensional geometry was established by the computerized mapping system. Using a boundary element inverse solution, 3360 virtual endocardial electrograms were computerized and used to derive isopotential maps. The earliest endocardial activation site, the exit site and the activation sequence of tachycardia or the critical isthmus of the reentry circuit were identified. Radiofrequency ablation with circular or linear lesion was performed at the target sites guided by the locator system.Results Six clinical types of tachycardia, 5 of which were ventricular tachycardia and one was concealed fasciculoventricular fiber mediated tachycardia, were induced by programmed stimulation. The mean cycle length of these tachycardias was 336.6±42.69 msec. The earliest activation site and the exit site of 5 mapped tachycardias were all identified using the system. One type of ventricular tachycardia was hemodynamically unstable and difficult to terminate, and could not be mapped. Among the 6 types of tachycardias, radiofrequency ablation was successful in 4. There was no complication during and after the procedure. During the mean follow-up of 6 months, no tachycardia recurred in the patients with a successful ablation.Conclusions The noncontact mapping system described in this study has advantage over conventional mapping techniques for refractory tachycardia. It is not only helpful for understanding the electrophysiologic mechanism of a complex case, but also suitable for mapping hemodynamically-intolerated and nonsustained ventricular tachycardia.
文摘Among the major natural disasters that occurred in 2010,the Haiti earthquake was a real turning point concerning the availability,dissemination and licensing of a huge quantity of geospatial data.In a few days several map products based on the analysis of remotely sensed data-sets were delivered to users.This demonstrated the need for reliable methods to validate the increasing variety of open source data and remote sensing-derived products for crisis management,with the aim to correctly spatially reference and interconnect these data with other global digital archives.As far as building damage assessment is concerned,the need for accurate field data to overcome the limitations of both vertical and oblique view satellite and aerial images was evident.To cope with the aforementioned need,a newly developed Low-Cost Mobile Mapping System(LCMMS)was deployed in Port-au-Prince(Haiti)and tested during a five-day survey in FebruaryMarch 2010.The system allows for acquisition of movies and single georeferenced frames by means of a transportable device easily installable(or adaptable)to every type of vehicle.It is composed of four webcams with a total field of view of about 180 degrees and one Global Positioning System(GPS)receiver,with the main aim to rapidly cover large areas for effective usage in emergency situations.The main technical features of the LCMMS,the operational use in the field(and related issues)and a potential approach to be adopted for the validation of satellite/aerial building damage assessments are thoroughly described in the article.
