Background Deep convolutional neural networks have garnered considerable attention in numerous machine learning applications,particularly in visual recognition tasks such as image and video analyses.There is a growing...Background Deep convolutional neural networks have garnered considerable attention in numerous machine learning applications,particularly in visual recognition tasks such as image and video analyses.There is a growing interest in applying this technology to diverse applications in medical image analysis.Automated three dimensional Breast Ultrasound is a vital tool for detecting breast cancer,and computer-assisted diagnosis software,developed based on deep learning,can effectively assist radiologists in diagnosis.However,the network model is prone to overfitting during training,owing to challenges such as insufficient training data.This study attempts to solve the problem caused by small datasets and improve model detection performance.Methods We propose a breast cancer detection framework based on deep learning(a transfer learning method based on cross-organ cancer detection)and a contrastive learning method based on breast imaging reporting and data systems(BI-RADS).Results When using cross organ transfer learning and BIRADS based contrastive learning,the average sensitivity of the model increased by a maximum of 16.05%.Conclusion Our experiments have demonstrated that the parameters and experiences of cross-organ cancer detection can be mutually referenced,and contrastive learning method based on BI-RADS can improve the detection performance of the model.展开更多
Background In recent years, with the rapid development of mobile Internet and Web3D technologies, a large number of web-based online 3D visualization applications have emerged. Web3D applications, including Web3D onli...Background In recent years, with the rapid development of mobile Internet and Web3D technologies, a large number of web-based online 3D visualization applications have emerged. Web3D applications, including Web3D online tourism, Web3D online architecture, Web3D online education environment, Web3D online medical care, and Web3D online shopping are examples of these applications that leverage 3D rendering on the web. These applications have pushed the boundaries of traditional web applications that use text, sound, image, video, and 2D animation as their main communication media, and resorted to 3D virtual scenes as the main interaction object, enabling a user experience that delivers a strong sense of immersion. This paper approached the emerging Web3D applications that generate stronger impacts on people's lives through “real-time rendering technology”, which is the core technology of Web3D. This paper discusses all the major 3D graphics APIs of Web3D and the well-known Web3D engines at home and abroad and classify the real-time rendering frameworks of Web3D applications into different categories. Results Finally, this study analyzed the specific demand posed by different fields to Web3D applications by referring to the representative Web3D applications in each particular field. Conclusions Our survey results show that Web3D applications based on real-time rendering have in-depth sectors of society and even family, which is a trend that has influence on every line of industry.展开更多
Objective To investigate the surgical technique and outcomes of replacement of chordae tendineae in mitral valve repair,and evaluate the value of real-time three-di-mensional transesophageal echocardiography in the pe...Objective To investigate the surgical technique and outcomes of replacement of chordae tendineae in mitral valve repair,and evaluate the value of real-time three-di-mensional transesophageal echocardiography in the perioperative period. Methods Thirty-one patients with mitral valve prolapse underwent mitral valve repair using chordae tendineae replacement concomitant with implantation展开更多
Liver metastases and hepatocellular carcinomas are two of the most common causes of cancer deaths in the world.Radiofrequency ablation(RFA) is a well recognized,effective and minimally invasive means of treating malig...Liver metastases and hepatocellular carcinomas are two of the most common causes of cancer deaths in the world.Radiofrequency ablation(RFA) is a well recognized,effective and minimally invasive means of treating malignant hepatic tumors.This article describes the use of contrast-enhanced 3D ultrasound(CE-3DUS) in the staging,targeting and follow-up of patients with liver tumors undergoing RFA.In particular,its value in the management of large hepatic lesions will be illustrated.Current limitations of CE-3DUS and future developments in the technique will also be discussed.In summary,CE-3DUS is useful in the RFA of liver tumors with improved detection and display of occult lesions and recurrence,in the assessment of lesional geometry and orientation for a more accurate planning and guidance of multiple RFA needle electrodes in large tumors and in the evaluation of residual or recurrent disease within the immediate and/or subsequent follow-up periods.展开更多
Landslides have occurred frequently in the Luoshan mining area because of disordered mining.This paper discusses the landforms and physiognomy,hydro-meteorology,formation lithology,and geologic structure of the Luosha...Landslides have occurred frequently in the Luoshan mining area because of disordered mining.This paper discusses the landforms and physiognomy,hydro-meteorology,formation lithology,and geologic structure of the Luoshan mining area.It also describes the factors influencing the slope stability of landslide No.Ⅲ,determines the general parameters and typical section plane,analyzes the stress-strain state of the No.Ⅲ slope,and calculates its safety factors with FLAC3 D under saturated and natural conditions.Based on a stability analysis,a remote real-time monitoring system was applied to the No.Ⅲ slope,and these monitoring data were collected and analyzed.展开更多
Objectives: This study focused on evaluating the value of transvaginal 3D ultrasound for the diagnosis and prognostic assessment of post-cesarean section uterine diverticulum. Materials and Methods: We retrospectively...Objectives: This study focused on evaluating the value of transvaginal 3D ultrasound for the diagnosis and prognostic assessment of post-cesarean section uterine diverticulum. Materials and Methods: We retrospectively analyzed the data from 32 patients with post-cesarean section uterine diverticulum over three recent years. In all patients, transvaginal 3D ultrasound was used to measure the size of the uterine diverticulum and the thickness of the lower uterine segment (LUS) and myometrium. Patients with a LUS with a myometrial thickness under 4 mm underwent resection and repair surgery;those with a LUS with a myometrial thickness over 4 mm underwent hysteroscopic resection. The postoperative sonograms were compared with preoperative images to evaluate the efficacy of various treatments. Results: The mean length, width and depth of the uterine diverticula were 18.30 ± 2.80 mm, 9.14 ± 3.20 mm and 11.49 ± 2.71 mm, respectively. The average LUS myometrial thickness was 3.40 ± 0.80 mm (with a range of 1.6 mm - 6.3 mm). After surgery, two patients’ sonograms still showed diverticula at the post-cesarean section scar, measuring 6 mm × 7 mm × 6 mm and 6 mm × 8 mm × 4 mm. There were significant differences in the size of uterine diverticula between preoperative and postoperative sonograms (P < 0.05) and the effective rate of surgery was 93.75% (30/32). Conclusions: Transvaginal 3D ultrasound is an accurate method for detecting post-cesarean section uterine diverticulum and is helpful for assessing surgical options and prognosis. The LUS myometrial thickness, which is considered as an optional index of post-cesarean section uterine diverticulum, should be measured routinely.展开更多
Purpose: This review examines the diagnostic value of transvaginal 3D ultrasound image texture analysis for the diagnosis of uterine adhesions. Materials and Methods: The total clinical data of 53 patients with uterin...Purpose: This review examines the diagnostic value of transvaginal 3D ultrasound image texture analysis for the diagnosis of uterine adhesions. Materials and Methods: The total clinical data of 53 patients with uterine adhesions diagnosed by hysteroscopy and the imaging data of transvaginal three-dimensional ultrasound from the Second Affiliated Hospital of Chongqing Medical University from June 2022 to August 2023 were retrospectively analysed. Based on hysteroscopic surgical records, patients were divided into two independent groups: normal endometrium and uterine adhesion sites. The samples were divided into a training set and a test set, and the transvaginal 3D ultrasound was used to outline the region of interest (ROI) and extract texture features for normal endometrium and uterine adhesions based on hysteroscopic surgical recordings, the training set data were feature screened and modelled using lasso regression and cross-validation, and the diagnostic efficacy of the model was assessed by applying the subjects’ operating characteristic (ROC) curves. Results: For each group, 290 texture feature parameters were extracted and three higher values were screened out, and the area under the curve of the constructed ultrasonographic scoring model was 0.658 and 0.720 in the training and test sets, respectively. Conclusion Relative clinical value of transvaginal three-dimensional ultrasound image texture analysis for the diagnosis of uterine adhesions.展开更多
This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, i...This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, it is not found to apply to gas simulation, since those methods based on SPH can't be used in real-time simulation due to their enormous particles and huge computation. This paper proposes a method for gas simulation based on SPH with a small number of particles. Firstly, the method computes the position and density of each particle in each point-in-time, and outlines the shape of the simulated gas based on those particles. Secondly the method uses the grid technique to refine the shape with the diffusion of particle's density under the control of grid, and get more lifelike simulation result. Each grid will be assigned density according to the particles in it. The density determines the final appearance of the grid. For ensuring the natural transition of the color between adjacent grids, we give a diffuse process of density between these grids and assign appropriate values to vertexes of these grids. The experimental results show that the proposed method can give better gas simulation and meet the request of real-time.展开更多
A real-time monitoring and 3D visualization analysis system is proposed for dam foundation curtain grouting. Based on the real-time control technology, the optimization method and the set theory, a mathematical model ...A real-time monitoring and 3D visualization analysis system is proposed for dam foundation curtain grouting. Based on the real-time control technology, the optimization method and the set theory, a mathematical model of the system is established. The real-time collection and transmission technology of the grouting data provides a data foundation for the system. The real-time grouting monitoring and dynamic alarming method helps the system control the grouting quality during the grouting process, thus, the abnormalities of grouting, such as jacking and hydraulic uplift, can be effectively controlled. In addition, the 3D grouting visualization analysis technology is proposed to establish the grouting information model(GIM). The GIM provides a platform to visualize and analyze the grouting process and results. The system has been applied to a hydraulic project of China as a case study, and the application results indicate that the real-time grouting monitoring and 3D visualization analysis for the grouting process can help engineers control the grouting quality more efficiently.展开更多
Fire rescue challenges and solutions have evolved from straightfor-ward plane rescue to encompass 3D space due to the rise of high-rise city buildings.Hence,this study facilitates a system with quick and simplified on...Fire rescue challenges and solutions have evolved from straightfor-ward plane rescue to encompass 3D space due to the rise of high-rise city buildings.Hence,this study facilitates a system with quick and simplified on-site launching and generates real-time location data,enabling fire rescuers to arrive at the intended spot faster and correctly for effective and precise rescue.Auto-positioning with step-by-step instructions is proposed when launching the locating system,while no extra measuring instrument like Total Station(TS)is needed.Real-time location tracking is provided via a 3D space real-time locating system(RTLS)constructed using Ultra-wide Bandwidth technology(UWB),which requires electromagnetic waves to pass through concrete walls.A hybrid weighted least squares with a time difference of arrival(WLS/TDOA)positioning method is proposed to address real path-tracking issues in 3D space and to meet RTLS requirements for quick computing in real-world applications.The 3D WLS/TDOA algorithm is theoretically constructed with the Cramer-Rao lower bound(CRLB).The computing complexity is reduced to the lower bound for embedded hardware to directly compute the time differential of the arriving signals using the time-to-digital converter(TDC).The results of the experiments show that the errors are controlled when the positioning algorithm is applied in various complicated situations to fulfill the requirements of engineering applications.The statistical analysis of the data reveals that the proposed UWB RTLS auto-positioning system can track target tags with an accuracy of 0.20 m.展开更多
Endoscopic ultrasound (EUS) has recently evolved through technological improvement of equipment,with a major clinical impact in digestive and mediastinal diseases.State-of-the-art EUS equipment now includes real-time ...Endoscopic ultrasound (EUS) has recently evolved through technological improvement of equipment,with a major clinical impact in digestive and mediastinal diseases.State-of-the-art EUS equipment now includes real-time sono-elastography,which might be useful for a better characterization of lesions and increased accuracy of differential diagnosis (for e.g.lymph nodes or focal pancreatic lesions).Contrast-enhanced EUS imaging is also available,and is already being used for the differential diagnosis of focal pancreatic masses.The recent development of low mechanical index contrast harmonic EUS imaging offers hope for improved diagnosis,staging and monitoring of anti-angiogenic treatment.Tridimensional EUS (3D-EUS) techniques can be applied to enhance the spatial understanding of EUS anatomy,especially for improved staging of tumors,obtained through a better assessment of the relationship with major surrounding vessels.Despite the progress gained through all these imaging techniques,they cannot replace cytological or histological diagnosis.However,real-time optical histological diagnosis can be achieved through the use of single-fiber confocal laser endomicroscopy techniques placed under real-time EUS-guidance through a 22G needle.Last,but not least,EUS-assisted natural orifice transluminal endoscopic surgery (NOTES) procedures offer a whole new area of imaging applications,used either for combination of NOTES peritoneoscopy and intraperitoneal EUS,but also for access of retroperitoneal organs through posterior EUS guidance.展开更多
Objective:?The study’s objective was to assess the accuracy of using prenatal 3-dimensional power Doppler analysis of vascular placental indices to accurately diagnose morbidly adherent placenta objectively. Backgrou...Objective:?The study’s objective was to assess the accuracy of using prenatal 3-dimensional power Doppler analysis of vascular placental indices to accurately diagnose morbidly adherent placenta objectively. Background:?Traditionally, 2D ultrasound was used for the diagnosis of a suspected morbidly adherent placenta (MAP) previa. More objective techniques like 3D power Doppler haven’t been well studied. Study Design:?A prospective cohort study?is?designed for women with gestational age between 28 and?32 weeks with suspected placenta previa. Patients were examined by 2D ultrasound which was used in management decisions.?3D Power Doppler’s VI, FI and VFI were measured during the same examination after manual tracing of placenta;data were blinded to obstetricians. Histopathology was performed to confirm MAP. Results: Our results showed that the 3D power Doppler VI ≥ 16 predicted the diagnosis of MAP with 100% sensitivity, 100% specificity which is better than those of 2D ultrasound. While VI > 33.1 measured by 3D Doppler predicted severe MAP with a sensitivity of 73.9% and specificity of 86.4%, which was superior to 2D ultrasound. Conclusion:?In patients with placenta previa, the 3D Doppler’s vascular index accurately predicts MAP. Furthermore, vascular and vascular flow indices of 3D Doppler were more predictive of severe cases of MAP compared to 2D ultrasound.展开更多
How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model mus...How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.展开更多
<strong>Background:</strong><span style="font-family:Verdana;"> Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA)</span><span style="font-family:""><...<strong>Background:</strong><span style="font-family:Verdana;"> Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA)</span><span style="font-family:""><span style="font-family:Verdana;"> syndrome is a rare congenital condition of the female urogenital tract, presenting intraoperative challenges. We demonstrate the utility of three dimensional intraoperative ultrasound to better delineate anatomy and aid in optimal resection of the vaginal septum. </span><b><span style="font-family:Verdana;">Case:</span></b><span style="font-family:Verdana;"> A 12-year-old female was referred to pediatric and adolescent gynecology for irregular periods and evaluation of her gynecologic organs. Imaging studies confirmed OHVIRA syndrome. She underwent uncomplicated vaginal septum resection, guided by three dimensional intraoperative ultrasound. </span><b><span style="font-family:Verdana;">Summary and Conclusion:</span></b><span style="font-family:Verdana;"> Intraoperative ultrasound can better delineate challenging anatomy. We show that three dimensional intraoperative ultrasound offers significant advantages over traditional two dimensional ultrasound and is a supplement to MRI, which may be helpful in complex anatomical cases like OHVIRA syndrome.</span></span>展开更多
基金Macao Polytechnic University Grant(RP/FCSD-01/2022RP/FCA-05/2022)Science and Technology Development Fund of Macao(0105/2022/A).
文摘Background Deep convolutional neural networks have garnered considerable attention in numerous machine learning applications,particularly in visual recognition tasks such as image and video analyses.There is a growing interest in applying this technology to diverse applications in medical image analysis.Automated three dimensional Breast Ultrasound is a vital tool for detecting breast cancer,and computer-assisted diagnosis software,developed based on deep learning,can effectively assist radiologists in diagnosis.However,the network model is prone to overfitting during training,owing to challenges such as insufficient training data.This study attempts to solve the problem caused by small datasets and improve model detection performance.Methods We propose a breast cancer detection framework based on deep learning(a transfer learning method based on cross-organ cancer detection)and a contrastive learning method based on breast imaging reporting and data systems(BI-RADS).Results When using cross organ transfer learning and BIRADS based contrastive learning,the average sensitivity of the model increased by a maximum of 16.05%.Conclusion Our experiments have demonstrated that the parameters and experiences of cross-organ cancer detection can be mutually referenced,and contrastive learning method based on BI-RADS can improve the detection performance of the model.
基金the Science and Technology Program of Educational Commission of Jiangxi Province,China(DA202104172)the Innovation and Entrepreneurship Course Program of Nanchang Hangkong University(KCPY1910)the Teaching Reform Research Program of Nanchang Hangkong University(JY21040).
文摘Background In recent years, with the rapid development of mobile Internet and Web3D technologies, a large number of web-based online 3D visualization applications have emerged. Web3D applications, including Web3D online tourism, Web3D online architecture, Web3D online education environment, Web3D online medical care, and Web3D online shopping are examples of these applications that leverage 3D rendering on the web. These applications have pushed the boundaries of traditional web applications that use text, sound, image, video, and 2D animation as their main communication media, and resorted to 3D virtual scenes as the main interaction object, enabling a user experience that delivers a strong sense of immersion. This paper approached the emerging Web3D applications that generate stronger impacts on people's lives through “real-time rendering technology”, which is the core technology of Web3D. This paper discusses all the major 3D graphics APIs of Web3D and the well-known Web3D engines at home and abroad and classify the real-time rendering frameworks of Web3D applications into different categories. Results Finally, this study analyzed the specific demand posed by different fields to Web3D applications by referring to the representative Web3D applications in each particular field. Conclusions Our survey results show that Web3D applications based on real-time rendering have in-depth sectors of society and even family, which is a trend that has influence on every line of industry.
文摘Objective To investigate the surgical technique and outcomes of replacement of chordae tendineae in mitral valve repair,and evaluate the value of real-time three-di-mensional transesophageal echocardiography in the perioperative period. Methods Thirty-one patients with mitral valve prolapse underwent mitral valve repair using chordae tendineae replacement concomitant with implantation
文摘Liver metastases and hepatocellular carcinomas are two of the most common causes of cancer deaths in the world.Radiofrequency ablation(RFA) is a well recognized,effective and minimally invasive means of treating malignant hepatic tumors.This article describes the use of contrast-enhanced 3D ultrasound(CE-3DUS) in the staging,targeting and follow-up of patients with liver tumors undergoing RFA.In particular,its value in the management of large hepatic lesions will be illustrated.Current limitations of CE-3DUS and future developments in the technique will also be discussed.In summary,CE-3DUS is useful in the RFA of liver tumors with improved detection and display of occult lesions and recurrence,in the assessment of lesional geometry and orientation for a more accurate planning and guidance of multiple RFA needle electrodes in large tumors and in the evaluation of residual or recurrent disease within the immediate and/or subsequent follow-up periods.
文摘Landslides have occurred frequently in the Luoshan mining area because of disordered mining.This paper discusses the landforms and physiognomy,hydro-meteorology,formation lithology,and geologic structure of the Luoshan mining area.It also describes the factors influencing the slope stability of landslide No.Ⅲ,determines the general parameters and typical section plane,analyzes the stress-strain state of the No.Ⅲ slope,and calculates its safety factors with FLAC3 D under saturated and natural conditions.Based on a stability analysis,a remote real-time monitoring system was applied to the No.Ⅲ slope,and these monitoring data were collected and analyzed.
文摘Objectives: This study focused on evaluating the value of transvaginal 3D ultrasound for the diagnosis and prognostic assessment of post-cesarean section uterine diverticulum. Materials and Methods: We retrospectively analyzed the data from 32 patients with post-cesarean section uterine diverticulum over three recent years. In all patients, transvaginal 3D ultrasound was used to measure the size of the uterine diverticulum and the thickness of the lower uterine segment (LUS) and myometrium. Patients with a LUS with a myometrial thickness under 4 mm underwent resection and repair surgery;those with a LUS with a myometrial thickness over 4 mm underwent hysteroscopic resection. The postoperative sonograms were compared with preoperative images to evaluate the efficacy of various treatments. Results: The mean length, width and depth of the uterine diverticula were 18.30 ± 2.80 mm, 9.14 ± 3.20 mm and 11.49 ± 2.71 mm, respectively. The average LUS myometrial thickness was 3.40 ± 0.80 mm (with a range of 1.6 mm - 6.3 mm). After surgery, two patients’ sonograms still showed diverticula at the post-cesarean section scar, measuring 6 mm × 7 mm × 6 mm and 6 mm × 8 mm × 4 mm. There were significant differences in the size of uterine diverticula between preoperative and postoperative sonograms (P < 0.05) and the effective rate of surgery was 93.75% (30/32). Conclusions: Transvaginal 3D ultrasound is an accurate method for detecting post-cesarean section uterine diverticulum and is helpful for assessing surgical options and prognosis. The LUS myometrial thickness, which is considered as an optional index of post-cesarean section uterine diverticulum, should be measured routinely.
文摘Purpose: This review examines the diagnostic value of transvaginal 3D ultrasound image texture analysis for the diagnosis of uterine adhesions. Materials and Methods: The total clinical data of 53 patients with uterine adhesions diagnosed by hysteroscopy and the imaging data of transvaginal three-dimensional ultrasound from the Second Affiliated Hospital of Chongqing Medical University from June 2022 to August 2023 were retrospectively analysed. Based on hysteroscopic surgical records, patients were divided into two independent groups: normal endometrium and uterine adhesion sites. The samples were divided into a training set and a test set, and the transvaginal 3D ultrasound was used to outline the region of interest (ROI) and extract texture features for normal endometrium and uterine adhesions based on hysteroscopic surgical recordings, the training set data were feature screened and modelled using lasso regression and cross-validation, and the diagnostic efficacy of the model was assessed by applying the subjects’ operating characteristic (ROC) curves. Results: For each group, 290 texture feature parameters were extracted and three higher values were screened out, and the area under the curve of the constructed ultrasonographic scoring model was 0.658 and 0.720 in the training and test sets, respectively. Conclusion Relative clinical value of transvaginal three-dimensional ultrasound image texture analysis for the diagnosis of uterine adhesions.
基金Supported by National Natural Science Foundation of China(No.61272024)
文摘This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, it is not found to apply to gas simulation, since those methods based on SPH can't be used in real-time simulation due to their enormous particles and huge computation. This paper proposes a method for gas simulation based on SPH with a small number of particles. Firstly, the method computes the position and density of each particle in each point-in-time, and outlines the shape of the simulated gas based on those particles. Secondly the method uses the grid technique to refine the shape with the diffusion of particle's density under the control of grid, and get more lifelike simulation result. Each grid will be assigned density according to the particles in it. The density determines the final appearance of the grid. For ensuring the natural transition of the color between adjacent grids, we give a diffuse process of density between these grids and assign appropriate values to vertexes of these grids. The experimental results show that the proposed method can give better gas simulation and meet the request of real-time.
基金Supported by the Innovative Research Groups of the National Natural Science Foundation of China(No.51321065)the National Natural Science Foundation of China(No.51339003 and No.51439005)
文摘A real-time monitoring and 3D visualization analysis system is proposed for dam foundation curtain grouting. Based on the real-time control technology, the optimization method and the set theory, a mathematical model of the system is established. The real-time collection and transmission technology of the grouting data provides a data foundation for the system. The real-time grouting monitoring and dynamic alarming method helps the system control the grouting quality during the grouting process, thus, the abnormalities of grouting, such as jacking and hydraulic uplift, can be effectively controlled. In addition, the 3D grouting visualization analysis technology is proposed to establish the grouting information model(GIM). The GIM provides a platform to visualize and analyze the grouting process and results. The system has been applied to a hydraulic project of China as a case study, and the application results indicate that the real-time grouting monitoring and 3D visualization analysis for the grouting process can help engineers control the grouting quality more efficiently.
文摘Fire rescue challenges and solutions have evolved from straightfor-ward plane rescue to encompass 3D space due to the rise of high-rise city buildings.Hence,this study facilitates a system with quick and simplified on-site launching and generates real-time location data,enabling fire rescuers to arrive at the intended spot faster and correctly for effective and precise rescue.Auto-positioning with step-by-step instructions is proposed when launching the locating system,while no extra measuring instrument like Total Station(TS)is needed.Real-time location tracking is provided via a 3D space real-time locating system(RTLS)constructed using Ultra-wide Bandwidth technology(UWB),which requires electromagnetic waves to pass through concrete walls.A hybrid weighted least squares with a time difference of arrival(WLS/TDOA)positioning method is proposed to address real path-tracking issues in 3D space and to meet RTLS requirements for quick computing in real-world applications.The 3D WLS/TDOA algorithm is theoretically constructed with the Cramer-Rao lower bound(CRLB).The computing complexity is reduced to the lower bound for embedded hardware to directly compute the time differential of the arriving signals using the time-to-digital converter(TDC).The results of the experiments show that the errors are controlled when the positioning algorithm is applied in various complicated situations to fulfill the requirements of engineering applications.The statistical analysis of the data reveals that the proposed UWB RTLS auto-positioning system can track target tags with an accuracy of 0.20 m.
基金Supported by "Utility of EUS and OCT for the minimal invasive evaluation of tumour neo-angiogenesis in the patients with digestive cancers" financed by the Romanian Ministry of Educationand Research-National University Research Council UEFISCSU-Ideas Program, No.239/2007
文摘Endoscopic ultrasound (EUS) has recently evolved through technological improvement of equipment,with a major clinical impact in digestive and mediastinal diseases.State-of-the-art EUS equipment now includes real-time sono-elastography,which might be useful for a better characterization of lesions and increased accuracy of differential diagnosis (for e.g.lymph nodes or focal pancreatic lesions).Contrast-enhanced EUS imaging is also available,and is already being used for the differential diagnosis of focal pancreatic masses.The recent development of low mechanical index contrast harmonic EUS imaging offers hope for improved diagnosis,staging and monitoring of anti-angiogenic treatment.Tridimensional EUS (3D-EUS) techniques can be applied to enhance the spatial understanding of EUS anatomy,especially for improved staging of tumors,obtained through a better assessment of the relationship with major surrounding vessels.Despite the progress gained through all these imaging techniques,they cannot replace cytological or histological diagnosis.However,real-time optical histological diagnosis can be achieved through the use of single-fiber confocal laser endomicroscopy techniques placed under real-time EUS-guidance through a 22G needle.Last,but not least,EUS-assisted natural orifice transluminal endoscopic surgery (NOTES) procedures offer a whole new area of imaging applications,used either for combination of NOTES peritoneoscopy and intraperitoneal EUS,but also for access of retroperitoneal organs through posterior EUS guidance.
文摘Objective:?The study’s objective was to assess the accuracy of using prenatal 3-dimensional power Doppler analysis of vascular placental indices to accurately diagnose morbidly adherent placenta objectively. Background:?Traditionally, 2D ultrasound was used for the diagnosis of a suspected morbidly adherent placenta (MAP) previa. More objective techniques like 3D power Doppler haven’t been well studied. Study Design:?A prospective cohort study?is?designed for women with gestational age between 28 and?32 weeks with suspected placenta previa. Patients were examined by 2D ultrasound which was used in management decisions.?3D Power Doppler’s VI, FI and VFI were measured during the same examination after manual tracing of placenta;data were blinded to obstetricians. Histopathology was performed to confirm MAP. Results: Our results showed that the 3D power Doppler VI ≥ 16 predicted the diagnosis of MAP with 100% sensitivity, 100% specificity which is better than those of 2D ultrasound. While VI > 33.1 measured by 3D Doppler predicted severe MAP with a sensitivity of 73.9% and specificity of 86.4%, which was superior to 2D ultrasound. Conclusion:?In patients with placenta previa, the 3D Doppler’s vascular index accurately predicts MAP. Furthermore, vascular and vascular flow indices of 3D Doppler were more predictive of severe cases of MAP compared to 2D ultrasound.
文摘How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.
文摘<strong>Background:</strong><span style="font-family:Verdana;"> Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA)</span><span style="font-family:""><span style="font-family:Verdana;"> syndrome is a rare congenital condition of the female urogenital tract, presenting intraoperative challenges. We demonstrate the utility of three dimensional intraoperative ultrasound to better delineate anatomy and aid in optimal resection of the vaginal septum. </span><b><span style="font-family:Verdana;">Case:</span></b><span style="font-family:Verdana;"> A 12-year-old female was referred to pediatric and adolescent gynecology for irregular periods and evaluation of her gynecologic organs. Imaging studies confirmed OHVIRA syndrome. She underwent uncomplicated vaginal septum resection, guided by three dimensional intraoperative ultrasound. </span><b><span style="font-family:Verdana;">Summary and Conclusion:</span></b><span style="font-family:Verdana;"> Intraoperative ultrasound can better delineate challenging anatomy. We show that three dimensional intraoperative ultrasound offers significant advantages over traditional two dimensional ultrasound and is a supplement to MRI, which may be helpful in complex anatomical cases like OHVIRA syndrome.</span></span>