Controlling multiple multi-joint fish-like robots has long captivated the attention of engineers and biologists,for which a fundamental but challenging topic is to robustly track the postures of the individuals in rea...Controlling multiple multi-joint fish-like robots has long captivated the attention of engineers and biologists,for which a fundamental but challenging topic is to robustly track the postures of the individuals in real time.This requires detecting multiple robots,estimating multi-joint postures,and tracking identities,as well as processing fast in real time.To the best of our knowledge,this challenge has not been tackled in the previous studies.In this paper,to precisely track the planar postures of multiple swimming multi-joint fish-like robots in real time,we propose a novel deep neural network-based method,named TAB-IOL.Its TAB part fuses the top-down and bottom-up approaches for vision-based pose estimation,while the IOL part with long short-term memory considers the motion constraints among joints for precise pose tracking.The satisfying performance of our TAB-IOL is verified by testing on a group of freely swimming fish-like robots in various scenarios with strong disturbances and by a deed comparison of accuracy,speed,and robustness with most state-of-the-art algorithms.Further,based on the precise pose estimation and tracking realized by our TAB-IOL,several formation control experiments are conducted for the group of fish-like robots.The results clearly demonstrate that our TAB-IOL lays a solid foundation for the coordination control of multiple fish-like robots in a real working environment.We believe our proposed method will facilitate the growth and development of related fields.展开更多
Ship.to.ship, ship.to.shore radio links empowered by Wi Fi, Wi MAX etc have been recently exploited to build maritime multi.hop mesh networks to provide internet services to on.ship users. However, because of the mobi...Ship.to.ship, ship.to.shore radio links empowered by Wi Fi, Wi MAX etc have been recently exploited to build maritime multi.hop mesh networks to provide internet services to on.ship users. However, because of the mobility of the vessels/ships and the large inter.ship distances, nodes in the maritime network are frequently disconnected, forcing data communication in the maritime mesh networks to be opportunistic and delay.tolerant. In this paper, we present Lane Post, an optimization approach for maritime delay.tolerant routing protocol. We exploit the shipping lane information to predict the rendezvous opportunities of the ships to optimize the route selection in delay.tolerant routing. In particular, we show that when the shipping lane information is available, an opportunistic routing graph(ORG) for each ship can be constructed to predict its multi.hop data routing opportunities to the other ships or to the shore. Based on the ORG, we develop an optimal route protocol(i.e., Lane Post) for each ship to minimize its delay of multi.hop packet delivery via dynamic programming. We discussed the ways of collecting shipping lane information by centralized method or distributed method.The proposed Lane Post protocol was evaluated by ONE, an open.source delay.tolerant network simulator, which shows its dramatic performance improvement in terms of delay reduction compared to the state.of.the.art opportunistic routing protocols.展开更多
Can a robotic gripper only operate when attached to a robotic arm?The application space of the traditional gripper is limited by the robotic arm.Giving robot grippers the ability to move will expand their range of app...Can a robotic gripper only operate when attached to a robotic arm?The application space of the traditional gripper is limited by the robotic arm.Giving robot grippers the ability to move will expand their range of applications.Inspired by rich behavioral repertoire observed in octopus,we implement an integrated multifunctional soft robotic gripper with 6 independently controlled Arms.It can execute 8 different gripping actions for different objects,such as irregular rigid/soft objects,elongated objects with arbitrary orientation,and plane/curved objects with larger sizes than the grippers.Moreover,the soft gripper can realize omnidirectional crawling and swimming by itself.The soft gripper can perform highly integrated tasks of releasing,crawling,swimming,grasping,and retrieving objects in a confined underwater environment.Experimental results demonstrate that the integrated capabilities of multimodal adaptive grasping and omnidirectional motions enable dexterous manipulations that traditional robotic arms cannot achieve.The soft gripper may apply to highly integrated and labor-intensive tasks in unstructured underwater environments,including ocean litter collecting,capture fishery,and archeological exploration.展开更多
Background:Serum human chorionic gonadotrophin(hCG)is higher in twin than that in singleton pregnancies.As hCG stimulates the thyroid to produce more free thyroxine(FT4),which may lead to decreased thyroid-stimulating...Background:Serum human chorionic gonadotrophin(hCG)is higher in twin than that in singleton pregnancies.As hCG stimulates the thyroid to produce more free thyroxine(FT4),which may lead to decreased thyroid-stimulating hormone(TSH)levels,the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester.This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies.Methods:Data of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018;160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges.We screened 480(3:1 paired)women with singleton pregnancies from the same database as controls.The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies.Results:First-trimester reference ranges(4–12 gestational weeks)for twin pregnancies were:TSH 0.69(0.01–3.35)mIU/L and FT416.38(12.45–23.34)pmol/L.Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks(0.62 vs.0.96 mIU/L,Z=-1.964,P=0.049);FT4 was not significantly different between the two groups.Compared to singleton pregnancies,median TSH was significantly lower(0.69 vs.1.27 mIU/L,Z=-6.538,P=0.000),and FT4 was significantly higher(16.38 vs.14.85 pmol/L,Z=-7.399,P=0.000)in twin pregnancies in the first trimester.Conclusions:Specific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction.Moreover,establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered.展开更多
People often have to queue for a busy service in many places around a city, and knowing the queue time can be helpful for making better activity plans to avoid long queues. Traditional solutions to the queue time moni...People often have to queue for a busy service in many places around a city, and knowing the queue time can be helpful for making better activity plans to avoid long queues. Traditional solutions to the queue time monitoring are based on pre-deployed infrastructures, such as cameras and infrared sensors, which are costly and fail to deliver the queue time information to scattered citizens. This paper presents CrowdQTE, a mobile crowdsensing system, which utilizes the sensor-enhanced mobile devices and crowd hu- man intelligence to monitor and provide real-time queue time information for various queuing scenarios. When people are waiting in a line, we utilize the accelerometer sensor data and ambient contexts to automatically detect the queueing behav- ior and calculate the queue time. When people are not waiting in a line, it estimates the queue time based on the information reported manually by participants. We evaluate the perfor- mance of the system with a two-week and 12-person deploy- ment using commercially-available smartphones. The results demonstrate that CrowdQTE is effective in estimating queu- ing status.展开更多
To simulate the passenger behavior in subway system, a Dynamic Parameters Cellular Automaton(DPCA) model is put forward in this paper. Pedestrian traffic flows during waiting, getting on or off, and traveling can be s...To simulate the passenger behavior in subway system, a Dynamic Parameters Cellular Automaton(DPCA) model is put forward in this paper. Pedestrian traffic flows during waiting, getting on or off, and traveling can be simulated. The typical scenario in Beijing Subway Line 13 is modeled to analyze the passenger behavior in subway system. By comparing simulation results with statistical ones, the correctness and practicality of the DPCA model are verified. At last, the additional results made by DPCA model can make contribution to passenger comfort analysis and pedestrian facility planning and guidance.展开更多
基金This work was supported in part by the National Natural Science Foundation of China(61973007,61633002).
文摘Controlling multiple multi-joint fish-like robots has long captivated the attention of engineers and biologists,for which a fundamental but challenging topic is to robustly track the postures of the individuals in real time.This requires detecting multiple robots,estimating multi-joint postures,and tracking identities,as well as processing fast in real time.To the best of our knowledge,this challenge has not been tackled in the previous studies.In this paper,to precisely track the planar postures of multiple swimming multi-joint fish-like robots in real time,we propose a novel deep neural network-based method,named TAB-IOL.Its TAB part fuses the top-down and bottom-up approaches for vision-based pose estimation,while the IOL part with long short-term memory considers the motion constraints among joints for precise pose tracking.The satisfying performance of our TAB-IOL is verified by testing on a group of freely swimming fish-like robots in various scenarios with strong disturbances and by a deed comparison of accuracy,speed,and robustness with most state-of-the-art algorithms.Further,based on the precise pose estimation and tracking realized by our TAB-IOL,several formation control experiments are conducted for the group of fish-like robots.The results clearly demonstrate that our TAB-IOL lays a solid foundation for the coordination control of multiple fish-like robots in a real working environment.We believe our proposed method will facilitate the growth and development of related fields.
基金supported in part by National Natural Science Foundation of China Grant 61672524the Fundamental Research Funds for the Central University+1 种基金the Research Funds of Renmin University of China, 2015030273National Key Technology Support Program 2014BAK12B06
文摘Ship.to.ship, ship.to.shore radio links empowered by Wi Fi, Wi MAX etc have been recently exploited to build maritime multi.hop mesh networks to provide internet services to on.ship users. However, because of the mobility of the vessels/ships and the large inter.ship distances, nodes in the maritime network are frequently disconnected, forcing data communication in the maritime mesh networks to be opportunistic and delay.tolerant. In this paper, we present Lane Post, an optimization approach for maritime delay.tolerant routing protocol. We exploit the shipping lane information to predict the rendezvous opportunities of the ships to optimize the route selection in delay.tolerant routing. In particular, we show that when the shipping lane information is available, an opportunistic routing graph(ORG) for each ship can be constructed to predict its multi.hop data routing opportunities to the other ships or to the shore. Based on the ORG, we develop an optimal route protocol(i.e., Lane Post) for each ship to minimize its delay of multi.hop packet delivery via dynamic programming. We discussed the ways of collecting shipping lane information by centralized method or distributed method.The proposed Lane Post protocol was evaluated by ONE, an open.source delay.tolerant network simulator, which shows its dramatic performance improvement in terms of delay reduction compared to the state.of.the.art opportunistic routing protocols.
基金supported in part by the National Natural Science Foundation of China under grants U22A2062,U23B2037,12272008,and 61973007in part by the Beijing Natural Science Foundation under grant 3242003。
文摘Can a robotic gripper only operate when attached to a robotic arm?The application space of the traditional gripper is limited by the robotic arm.Giving robot grippers the ability to move will expand their range of applications.Inspired by rich behavioral repertoire observed in octopus,we implement an integrated multifunctional soft robotic gripper with 6 independently controlled Arms.It can execute 8 different gripping actions for different objects,such as irregular rigid/soft objects,elongated objects with arbitrary orientation,and plane/curved objects with larger sizes than the grippers.Moreover,the soft gripper can realize omnidirectional crawling and swimming by itself.The soft gripper can perform highly integrated tasks of releasing,crawling,swimming,grasping,and retrieving objects in a confined underwater environment.Experimental results demonstrate that the integrated capabilities of multimodal adaptive grasping and omnidirectional motions enable dexterous manipulations that traditional robotic arms cannot achieve.The soft gripper may apply to highly integrated and labor-intensive tasks in unstructured underwater environments,including ocean litter collecting,capture fishery,and archeological exploration.
基金This work was supported by grants from the Interdisci-plinary Clinical Research Project of Peking University First Hospital(No.2017CR27)the Capital Foundation of Medical Developments(No.2018-4-4077)the Clinical Medicine Plus X-Young Scholars Project of Peking University(supported by the Fundamental Research Funds for the Central Universities).
文摘Background:Serum human chorionic gonadotrophin(hCG)is higher in twin than that in singleton pregnancies.As hCG stimulates the thyroid to produce more free thyroxine(FT4),which may lead to decreased thyroid-stimulating hormone(TSH)levels,the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester.This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies.Methods:Data of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018;160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges.We screened 480(3:1 paired)women with singleton pregnancies from the same database as controls.The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies.Results:First-trimester reference ranges(4–12 gestational weeks)for twin pregnancies were:TSH 0.69(0.01–3.35)mIU/L and FT416.38(12.45–23.34)pmol/L.Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks(0.62 vs.0.96 mIU/L,Z=-1.964,P=0.049);FT4 was not significantly different between the two groups.Compared to singleton pregnancies,median TSH was significantly lower(0.69 vs.1.27 mIU/L,Z=-6.538,P=0.000),and FT4 was significantly higher(16.38 vs.14.85 pmol/L,Z=-7.399,P=0.000)in twin pregnancies in the first trimester.Conclusions:Specific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction.Moreover,establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered.
基金This work was mainly funded by the National Natural Science Foundation of China （Grant No. 61572048）, Research Fund from China Electric Power Research Institute （JS71-16-005）, and Microsoft Col- laboration Research Grant. Besides, the work was partially supported by the Fundamental Research Funds for the Central Universities （106112015CD-JXY180001）, Open Research Fund Program of Shenzhen Key Laboratory of Spatial Smart Sensing and Services （Shenzhen University, China）, and Chongqing Basic and Frontier Research Program （cstc2015jcyjA00016）.
文摘People often have to queue for a busy service in many places around a city, and knowing the queue time can be helpful for making better activity plans to avoid long queues. Traditional solutions to the queue time monitoring are based on pre-deployed infrastructures, such as cameras and infrared sensors, which are costly and fail to deliver the queue time information to scattered citizens. This paper presents CrowdQTE, a mobile crowdsensing system, which utilizes the sensor-enhanced mobile devices and crowd hu- man intelligence to monitor and provide real-time queue time information for various queuing scenarios. When people are waiting in a line, we utilize the accelerometer sensor data and ambient contexts to automatically detect the queueing behav- ior and calculate the queue time. When people are not waiting in a line, it estimates the queue time based on the information reported manually by participants. We evaluate the perfor- mance of the system with a two-week and 12-person deploy- ment using commercially-available smartphones. The results demonstrate that CrowdQTE is effective in estimating queu- ing status.
基金partially supported by the National Key Basic Research and Development (973) Program of China (No. 2012CB725405)the National HighTech Research and Development (863) Program of China (No. 2012AA112305)the National Natural Science Foundation of China (No. 61273238)
文摘To simulate the passenger behavior in subway system, a Dynamic Parameters Cellular Automaton(DPCA) model is put forward in this paper. Pedestrian traffic flows during waiting, getting on or off, and traveling can be simulated. The typical scenario in Beijing Subway Line 13 is modeled to analyze the passenger behavior in subway system. By comparing simulation results with statistical ones, the correctness and practicality of the DPCA model are verified. At last, the additional results made by DPCA model can make contribution to passenger comfort analysis and pedestrian facility planning and guidance.
