This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe...This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.展开更多
The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlle...The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.展开更多
This paper presents a Nonlinear Model Predictive Controller(NMPC)for the path following of autonomous vehicles and an algorithm to adaptively adjust the preview distance.The prediction model includes vehicle dynamics,...This paper presents a Nonlinear Model Predictive Controller(NMPC)for the path following of autonomous vehicles and an algorithm to adaptively adjust the preview distance.The prediction model includes vehicle dynamics,path following dynamics,and system input dynamics.The single-track vehicle model considers the vehicle’s coupled lateral and longitudinal dynamics,as well as nonlinear tire forces.The tracking error dynamics are derived based on the curvilinear coordinates.The cost function is designed to minimize path tracking errors and control effort while considering constraints such as actuator bounds and tire grip limits.An algorithm that utilizes the optimal preview distance vector to query the corresponding reference curvature and reference speed.The length of the preview path is adaptively adjusted based on the vehicle speed,heading error,and path curvature.We validate the controller performance in a simulation environment with the autonomous racing scenario.The simulation results show that the vehicle accurately follows the highly dynamic path with small tracking errors.The maximum preview distance can be prior estimated and guidance the selection of the prediction horizon for NMPC.展开更多
Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest f...Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects.展开更多
Introduction: Despite the known benefits of newborn follow-up clinics, attendance has historically been difficult. Infants with reported follow-up difficulty have a greater incidence of severe sensorimotor and cogniti...Introduction: Despite the known benefits of newborn follow-up clinics, attendance has historically been difficult. Infants with reported follow-up difficulty have a greater incidence of severe sensorimotor and cognitive deficits and poorer access to early intervention programs. Our objective was to determine the parent-reported reasons for loss-to-follow up in patients hospitalised at the neonatology unit of Laquintinie Hospital. Methodology: We carried out a cross-sectional study through phone interviews with parents/caregivers of patients hospitalised at Laquintinie over a 2-year period from 1st January 2021 to 31st December 2022. A non-standardised structured interview guide was used for data collection. Loss-to-follow up referred to absence to at least one visit as recorded in the neonatal follow-up chart. All necessary administrative and ethical considerations were duly respected. Results: Most neonates were born through vaginal delivery (n = 313, 69.45%). The neonates were admitted at a median gestational age of 33 weeks (Q1-Q3;32 - 35) and the median duration of hospitalisation was 12 days (Q1 - Q3;8 - 18). A total of 23 neonates had died at the time of interview giving a mortality rate of 5.1%. The three most reported reasons for loss-to-follow-up was lack of money (n = 310, 68.13%), assumption that follow-up had ended (n = 37, 8.13%), and newborn that died (n = 23, 5.1%). Conclusion: This study highlights the significant impact of financial constraints and absence of a robust follow-up system on poor uptake of neonatal follow-up post-discharge in resource limited settings like Cameroon. Our results serve as advocacy for national health insurance especially in neonates.展开更多
描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重...描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重要的内容,由于文法中终结符和非终结符个数很多,考虑 FIRST 和 FOLLOW 集合的并行处理方法,对并行编译处理和提高效率有其理论和现实意义。展开更多
A novel neuMOS source follower circuit is presented.The cell can complete the s ource follower function even if the input voltage is lower than the threshold of the source follower,thus high-precision operation of th...A novel neuMOS source follower circuit is presented.The cell can complete the s ource follower function even if the input voltage is lower than the threshold of the source follower,thus high-precision operation of the circuit is achieved. The simulation and the measurement results show that its precision is higher tha n that of other neuMOS source follower circuits.展开更多
A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic...A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic running and abnormal information input from the sensors are chosen out. In addition, the functions of real-time display, information exchanging interface, determination and operation interweaving in the 3 user services are separated into 5 object-oriented classes. Moreover, the 5 classes are organized in the visual development environment. At last, experimental result proves the validity and reliability of the control application.展开更多
A model following adaptive control system for CSIM is presented in this paper. A dynamic mathematical model of slip control based system is obtained. With the help of model reducing technique, full order model is ...A model following adaptive control system for CSIM is presented in this paper. A dynamic mathematical model of slip control based system is obtained. With the help of model reducing technique, full order model is reduced to simplify the design without degrading much of the performance. Model following adaptive control laws in discrete form are derived. These laws satisfy the hyperstability condition for taking care of the load and machine parameter changes of the drive. A microprocessor 8098 is used to develop the speed controller. The implementation of the control system uses only available variables of the reference model and the controlled plant. Experimental results are given to demonstrate the good performance of the system.展开更多
AIM: To investigate the prevalence of and risk factors for non-alcoholic fatty liver disease(NAFLD) in a Chinese population.METHODS: A total of 1948 adults from China was followed for 8 years. A cross-sectional study ...AIM: To investigate the prevalence of and risk factors for non-alcoholic fatty liver disease(NAFLD) in a Chinese population.METHODS: A total of 1948 adults from China was followed for 8 years. A cross-sectional study was performed to investigate the prevalence of NAFLD at baseline, and then the participants were followed for 8 years to investigate risk factors for the development of NAFLD.RESULTS: A total of 1948 participants were enrolled at baseline, of whom 691 were diagnosed with NAFLD. During the 8-year follow-up, 337 baseline NAFLD-free participants developed NAFLD. They had a greaterincrease in body mass index(BMI), serum uric acid, fasting plasma glucose, very low-density lipoprotein cholesterol and a considerable decrease in high-density lipoprotein cholesterol. 123 participants who had NAFLD at baseline lost NAFLD during the 8-year follow-up period. They had a greater decrease in BMI, fasting plasma glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase.CONCLUSION: NAFLD is prevalent in Chinese population with a rapidly increasing tendency. It can be reversed when patients lose their weight, control their hyperlipidemia and hyperglycemia, and reduce the liver enzyme levels.展开更多
Gastric cancer remains the second most frequent cause of cancer-related mortality in the world. Screening programs in some Asian countries are impractical in the majority of other countries worldwide. Therefore, follo...Gastric cancer remains the second most frequent cause of cancer-related mortality in the world. Screening programs in some Asian countries are impractical in the majority of other countries worldwide. Therefore, follow-up of precancerous lesions is advisable for secondary gastric cancer prevention. Intestinal metaplasia (IM) is recognized as a precancerous lesion for gastric cancer, increasing the risk by 6-fold. IM is highly prevalent in the general population, being detected in nearly 1 of every 4 patients undergoing upper endoscopy. The IM prevalence rate is significantly higher in patients with Helicobacter pylori (H. pylori) infection, in first-degree relatives of gastric cancer patients, in smokers and it increases with patient age. IM is the "breaking point" in the gastric carcinogenesis cascade and does not appear to regress following H. pylori eradication, although the cure of infection may slow its progression. Gastric cancer risk is higher in patients with incomplete-type IM, in those with both antral and gastric body involvement, and the risk significantly increases with IM extension over 20% of the gastric mucosa. Scheduled endoscopic control could be cost-effective in IM patients, depending on the yearly incidence of gastric cancer in IM patients, the stage of gastric cancer at diagnosis discovered at surveillance, and the cost of endoscopy. As a pragmatic behavior, yearly endoscopic control would appear justified in all IM patients with at least one of these conditions: (1) IM extension > 20%; (2) the presence of incomplete type IM; (3) first-degree relative of gastric cancer patients; and (4) smokers. In the remaining IM patients, a less intensive (2-3 years) could be proposed.展开更多
In this study we evaluate the oncological and functional results of the largest cohort of patients in China treated by laparoscopic radical prostatectomy （LRP） and with at least 3 years of follow-up. 126 inconsecuti...In this study we evaluate the oncological and functional results of the largest cohort of patients in China treated by laparoscopic radical prostatectomy （LRP） and with at least 3 years of follow-up. 126 inconsecutive patients （range 56-78 years, median 62.5） who had an LRP were retrospectively analyzed. The mean prostate specific antigen level and Gleason score was 13.4 ng mL^-1 and 6.4, respectively. Twenty-seven patients had unilateral or bilateral nerve preservation and 29 had pelvic lymphadenectomy. Multivariate analysis was used to adjust for differences in clinical and pathological features when comparing the risk for biochemical progression-free survival （bPFS）. Urinary continence was assessed by incontinence questionnaire and erectile function by the Sexual Health Inventory for Men score. The mean operative duration was 250 min and blood loss 354 mL. Five patients received blood transfusion and nine had complications, including rectal injury （two）, ureteral injury （one）, active bleeding （one）, bladder neck stenosis （two）, paralytic ileus （one）, subcutaneous hematoma （one） and port-site hernia （one）. The overall positive surgical margin rate was 20.6% and correlated with pathological stage and Gleason score respectively （P = 0.03, P 〈 0.001 respectively）. All patients had 〉 3 years of follow-up （range 3-6.75 years, mean 4.6, median 4.75）. At 3 years of follow-up, the overall survival rate was 100% and the bPFS was 81.0% in all patients; 124 patients （98.4%） were continent; 22 of 27 patients （81.5%） who underwent nerve preservation retained erectile function. Our series confirms that LRP is an effective, safe and precise technique at Chinese institution.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62173312 and 61803348in part by the National Major Scientific Instruments Development Project under Grant No.61927807+3 种基金in part by the Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi Province Science Foundation for Excellent Youthsin part by the Shanxi"1331 Project"Key Subjects Construction(1331KSC)in part by Graduate Innovation Project of Shanxi Province under Grant No.2021Y617。
文摘This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.
基金supported by the National Natural Science Foundation of China(62073019)。
文摘The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.
基金“National Science and Technology Council”(NSTC 111-2221-E-027-088)。
文摘This paper presents a Nonlinear Model Predictive Controller(NMPC)for the path following of autonomous vehicles and an algorithm to adaptively adjust the preview distance.The prediction model includes vehicle dynamics,path following dynamics,and system input dynamics.The single-track vehicle model considers the vehicle’s coupled lateral and longitudinal dynamics,as well as nonlinear tire forces.The tracking error dynamics are derived based on the curvilinear coordinates.The cost function is designed to minimize path tracking errors and control effort while considering constraints such as actuator bounds and tire grip limits.An algorithm that utilizes the optimal preview distance vector to query the corresponding reference curvature and reference speed.The length of the preview path is adaptively adjusted based on the vehicle speed,heading error,and path curvature.We validate the controller performance in a simulation environment with the autonomous racing scenario.The simulation results show that the vehicle accurately follows the highly dynamic path with small tracking errors.The maximum preview distance can be prior estimated and guidance the selection of the prediction horizon for NMPC.
文摘Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects.
文摘Introduction: Despite the known benefits of newborn follow-up clinics, attendance has historically been difficult. Infants with reported follow-up difficulty have a greater incidence of severe sensorimotor and cognitive deficits and poorer access to early intervention programs. Our objective was to determine the parent-reported reasons for loss-to-follow up in patients hospitalised at the neonatology unit of Laquintinie Hospital. Methodology: We carried out a cross-sectional study through phone interviews with parents/caregivers of patients hospitalised at Laquintinie over a 2-year period from 1st January 2021 to 31st December 2022. A non-standardised structured interview guide was used for data collection. Loss-to-follow up referred to absence to at least one visit as recorded in the neonatal follow-up chart. All necessary administrative and ethical considerations were duly respected. Results: Most neonates were born through vaginal delivery (n = 313, 69.45%). The neonates were admitted at a median gestational age of 33 weeks (Q1-Q3;32 - 35) and the median duration of hospitalisation was 12 days (Q1 - Q3;8 - 18). A total of 23 neonates had died at the time of interview giving a mortality rate of 5.1%. The three most reported reasons for loss-to-follow-up was lack of money (n = 310, 68.13%), assumption that follow-up had ended (n = 37, 8.13%), and newborn that died (n = 23, 5.1%). Conclusion: This study highlights the significant impact of financial constraints and absence of a robust follow-up system on poor uptake of neonatal follow-up post-discharge in resource limited settings like Cameroon. Our results serve as advocacy for national health insurance especially in neonates.
文摘描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重要的内容,由于文法中终结符和非终结符个数很多,考虑 FIRST 和 FOLLOW 集合的并行处理方法,对并行编译处理和提高效率有其理论和现实意义。
文摘A novel neuMOS source follower circuit is presented.The cell can complete the s ource follower function even if the input voltage is lower than the threshold of the source follower,thus high-precision operation of the circuit is achieved. The simulation and the measurement results show that its precision is higher tha n that of other neuMOS source follower circuits.
文摘A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic running and abnormal information input from the sensors are chosen out. In addition, the functions of real-time display, information exchanging interface, determination and operation interweaving in the 3 user services are separated into 5 object-oriented classes. Moreover, the 5 classes are organized in the visual development environment. At last, experimental result proves the validity and reliability of the control application.
文摘A model following adaptive control system for CSIM is presented in this paper. A dynamic mathematical model of slip control based system is obtained. With the help of model reducing technique, full order model is reduced to simplify the design without degrading much of the performance. Model following adaptive control laws in discrete form are derived. These laws satisfy the hyperstability condition for taking care of the load and machine parameter changes of the drive. A microprocessor 8098 is used to develop the speed controller. The implementation of the control system uses only available variables of the reference model and the controlled plant. Experimental results are given to demonstrate the good performance of the system.
基金Supported by the National Natural Science Foundation of China,No.81372425 and No.81460634the Key Lab Project of the Xinjiang Science and Technology Bureau,No.2014KL002
文摘AIM: To investigate the prevalence of and risk factors for non-alcoholic fatty liver disease(NAFLD) in a Chinese population.METHODS: A total of 1948 adults from China was followed for 8 years. A cross-sectional study was performed to investigate the prevalence of NAFLD at baseline, and then the participants were followed for 8 years to investigate risk factors for the development of NAFLD.RESULTS: A total of 1948 participants were enrolled at baseline, of whom 691 were diagnosed with NAFLD. During the 8-year follow-up, 337 baseline NAFLD-free participants developed NAFLD. They had a greaterincrease in body mass index(BMI), serum uric acid, fasting plasma glucose, very low-density lipoprotein cholesterol and a considerable decrease in high-density lipoprotein cholesterol. 123 participants who had NAFLD at baseline lost NAFLD during the 8-year follow-up period. They had a greater decrease in BMI, fasting plasma glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase.CONCLUSION: NAFLD is prevalent in Chinese population with a rapidly increasing tendency. It can be reversed when patients lose their weight, control their hyperlipidemia and hyperglycemia, and reduce the liver enzyme levels.
文摘Gastric cancer remains the second most frequent cause of cancer-related mortality in the world. Screening programs in some Asian countries are impractical in the majority of other countries worldwide. Therefore, follow-up of precancerous lesions is advisable for secondary gastric cancer prevention. Intestinal metaplasia (IM) is recognized as a precancerous lesion for gastric cancer, increasing the risk by 6-fold. IM is highly prevalent in the general population, being detected in nearly 1 of every 4 patients undergoing upper endoscopy. The IM prevalence rate is significantly higher in patients with Helicobacter pylori (H. pylori) infection, in first-degree relatives of gastric cancer patients, in smokers and it increases with patient age. IM is the "breaking point" in the gastric carcinogenesis cascade and does not appear to regress following H. pylori eradication, although the cure of infection may slow its progression. Gastric cancer risk is higher in patients with incomplete-type IM, in those with both antral and gastric body involvement, and the risk significantly increases with IM extension over 20% of the gastric mucosa. Scheduled endoscopic control could be cost-effective in IM patients, depending on the yearly incidence of gastric cancer in IM patients, the stage of gastric cancer at diagnosis discovered at surveillance, and the cost of endoscopy. As a pragmatic behavior, yearly endoscopic control would appear justified in all IM patients with at least one of these conditions: (1) IM extension > 20%; (2) the presence of incomplete type IM; (3) first-degree relative of gastric cancer patients; and (4) smokers. In the remaining IM patients, a less intensive (2-3 years) could be proposed.
基金Acknowledgment This study was supported by the National Natural Science Foundation of China （30772178）, Research Fund for the Doctoral Program of Higher Education of China （20060558032）, Natural Science Foundation of Guangdong Province （7117362） and the Program of 5010 of SunYat-Sen University （2007028）. The authors declare no conflict of interest.
文摘In this study we evaluate the oncological and functional results of the largest cohort of patients in China treated by laparoscopic radical prostatectomy （LRP） and with at least 3 years of follow-up. 126 inconsecutive patients （range 56-78 years, median 62.5） who had an LRP were retrospectively analyzed. The mean prostate specific antigen level and Gleason score was 13.4 ng mL^-1 and 6.4, respectively. Twenty-seven patients had unilateral or bilateral nerve preservation and 29 had pelvic lymphadenectomy. Multivariate analysis was used to adjust for differences in clinical and pathological features when comparing the risk for biochemical progression-free survival （bPFS）. Urinary continence was assessed by incontinence questionnaire and erectile function by the Sexual Health Inventory for Men score. The mean operative duration was 250 min and blood loss 354 mL. Five patients received blood transfusion and nine had complications, including rectal injury （two）, ureteral injury （one）, active bleeding （one）, bladder neck stenosis （two）, paralytic ileus （one）, subcutaneous hematoma （one） and port-site hernia （one）. The overall positive surgical margin rate was 20.6% and correlated with pathological stage and Gleason score respectively （P = 0.03, P 〈 0.001 respectively）. All patients had 〉 3 years of follow-up （range 3-6.75 years, mean 4.6, median 4.75）. At 3 years of follow-up, the overall survival rate was 100% and the bPFS was 81.0% in all patients; 124 patients （98.4%） were continent; 22 of 27 patients （81.5%） who underwent nerve preservation retained erectile function. Our series confirms that LRP is an effective, safe and precise technique at Chinese institution.
