This paper presents an untethered pneumatic soft robot which can crawl both in horizontal and vertical pipes with different sizes and cross sections.This robot uses modular origami inspired soft-rigid hybrid actuator ...This paper presents an untethered pneumatic soft robot which can crawl both in horizontal and vertical pipes with different sizes and cross sections.This robot uses modular origami inspired soft-rigid hybrid actuator to produce telescoping and anchoring movements powered by vacuum pressure.The introduction of grooves to valley crease significantly lowers the full contraction vacuum pressure and improves the response,allowing the system can be driven by an onboard micro vacuum pump,enabling the possibility of miniaturization,integration,and untethered operation of the robot.A series of crawling experiments in pipes with different sizes and cross sections constructed by acrylic are conducted to validate the crawling performance of the robot.Within square cross-section pipes,the robot can achieve a velocity of 9.4 mm/s in horizontal crawling and 7.7 mm/s in vertical upward crawling.For horizontal crawling in circular pipes,it can reach a velocity of 8.0 mm/s.When fully charged,the robot can crawl for 40 min with a mileage of 16.649 m,which is sufficient for most drainage and industrial pipelines detection tasks.The robot demonstrates excellent endurance and speed performance that exceed most existing untethered soft pipe crawling robots.展开更多
In this study,we present a small,integrated jumping-crawling robot capable of intermittent jumping and self-resetting.Compared to robots with a single mode of locomotion,this multi-modal robot exhibits enhanced obstac...In this study,we present a small,integrated jumping-crawling robot capable of intermittent jumping and self-resetting.Compared to robots with a single mode of locomotion,this multi-modal robot exhibits enhanced obstacle-surmounting capabilities.To achieve this,the robot employs a novel combination of a jumping module and a crawling module.The jumping module features improved energy storage capacity and an active clutch.Within the constraints of structural robustness,the jumping module maximizes the explosive power of the linear spring by utilizing the mechanical advantage of a closed-loop mechanism and controls the energy flow of the jumping module through an active clutch mechanism.Furthermore,inspired by the limb movements of tortoises during crawling and self-righting,a single-degree-of-freedom spatial four-bar crawling mechanism was designed to enable crawling,steering,and resetting functions.To demonstrate its practicality,the integrated jumping-crawling robot was tested in a laboratory environment for functions such as jumping,crawling,self-resetting,and steering.Experimental results confirmed the feasibility of the proposed integrated jumping-crawling robot.展开更多
A novel three-dimensional-fiber reinforced soft pneumatic actuator(3D-FRSPA)inspired by crab claw and human hand structure that can bend and deform independently in each segment is proposed.It has an omni-directional ...A novel three-dimensional-fiber reinforced soft pneumatic actuator(3D-FRSPA)inspired by crab claw and human hand structure that can bend and deform independently in each segment is proposed.It has an omni-directional bending configuration,and the fibers twined symmetrically on both sides to improve the bending performance of FRSPA.In this paper,the static and kinematic analysis of 3D-FRSPA are carried out in detail.The effects of fiber,pneumatic chamber and segment length,and circular air chamber radius of 3D-FRSPA on the mechanical performance of the actuator are discussed,respectively.The soft mobile robot composed of 3D-FRSPA has the ability to crawl.Finally,the crawling processes of the soft mobile robot on different road conditions are studied,respectively,and the motion mechanism of the mobile actuator is shown.The numerical results show that the soft mobile robots have a good comprehensive performance,which verifies the correctness of the proposedmodel.This work shows that the proposed structures have great potential in complex road conditions,unknown space detection and other operations.展开更多
This paper focuses on a newly developed transmission for a milli-scale eight-legged crawling robot called OriSCO.The transmission allows intuitive steering by directly changing the direction of the propulsion force.Th...This paper focuses on a newly developed transmission for a milli-scale eight-legged crawling robot called OriSCO.The transmission allows intuitive steering by directly changing the direction of the propulsion force.The transmission is based on the constrained spherical six-bar linkage.The constrained spherical six-bar linkage passes only reciprocating motion out of the motor’s rotating motion,allowing the crawling legs to kick the ground and obtain propulsion.Steering is achieved by adjusting the geometric constraints of the spherical six-bar using a servomotor,allowing the direction of propulsion to be changed.As a result,the OriSCO can move along the ground at a speed of 2.15 body lengths/s,and the robot is 60 mm long.展开更多
Purpose To determine the association between lower-body strength and lower-body power capacities with sprint swimming performance in adolescent competitive swimmers.Methods A total of 44 front crawl swimmers(27 males ...Purpose To determine the association between lower-body strength and lower-body power capacities with sprint swimming performance in adolescent competitive swimmers.Methods A total of 44 front crawl swimmers(27 males and 17 females)performed anthropometric assessments,lower-body strength tests(half squat maximum isometric strength,dynamic half squat with 20,30 and 40%of the maximum isometric strength,and knee extension maximum isometric strength)and lower-body power tests(squat jump[SJ],countermovement jump[CMJ]and Abalakov jump).Further front crawl swimming best times in 50 and 100 m were recorded from official swimming competitions and front crawl technique was assessed by an experienced coach using a visual analogue scale.Results Swimming performance was correlated with lower-body power variables(SJ[r=−0.573 for 50 m and−0.642 for 100 m],CMJ[r=−0.497 for 50 m and−0.544 for 100 m],and Abalakov jump[r=−0.452 for 50 m and−0.415 for 100 m];p≤0.05)and lower-body strength(half squat maximum isometric strength[r=−0.430 for 50 m and−0.443 for 100 m];p≤0.05)in males but not in females.Further linear regression models showed that only lower-body power predicted both 50 m(Abalakov jump;r^(2)=0.58;change in r^(2)=0.18)and 100 m(SJ;r^(2)=0.66;change in r^(2)=0.15)performance in male swimmers.Conclusions This study emphasizes the greater association between lower-body power and sprint front crawl performance in adolescent males compared to females.Practical tests(i.e.,SJ and Abalakov jump)are shown to predict front crawl swimming performance,which may facilitate the performance control by coaches and trainers.展开更多
Abstract—Focused crawlers （also known as subjectoriented crawlers）, as the core part of vertical search engine, collect topic-specific web pages as many as they can to form a subject-oriented corpus for the latter ...Abstract—Focused crawlers （also known as subjectoriented crawlers）, as the core part of vertical search engine, collect topic-specific web pages as many as they can to form a subject-oriented corpus for the latter data analyzing or user querying. This paper demonstrates that the popular algorithms utilized at the process of focused web crawling, basically refer to webpage analyzing algorithms and crawling strategies （prioritize the uniform resource locator （URLs） in the queue）. Advantages and disadvantages of three crawling strategies are shown in the first experiment, which indicates that the best-first search with an appropriate heuristics is a smart choice for topic-oriented crawlingwhile the depth-first search is helpless in focused crawling. Besides, another experiment on comparison of improved ones （with a webpage analyzing algorithm added） is carried out to verify that crawling strategies alone are not quite efficient for focused crawling and in most cases their mutual efforts are taken into consideration. In light of the experiment results and recent researches, some points on the research tendency of focused crawler algorithms are suggested.展开更多
In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dyna...In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driv- ing for the vehicle, a control strategy of the clutch was designed. The strategy increased the.slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was de- signed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.展开更多
Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoele...Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoelectric effect of piezoelectric ceramics was proposed.The three legs of the robot were equipped with piezoelectric bimorphs as drivers,respectively.The motion principles were analyzed and the overall force analysis was carried out with the theoretical mechanics method.The natural frequency,mode shape and amplitude were analyzed with simulation software COMSOL Multiphysics,the optimal size was determined through parametric analysis,and then the micro three-legged crawling robot was manufactured.The effects of different driving voltages,different driving frequencies,different motion bases and different loads on the motion speed of the robot were tested.It is shown that the maximum speed of single-leg driving was 35.41 cm/s,the switching ability between different motion directions was measured,and the movements in six different directions were achieved.It is demonstrated the feasibility of multi-directional motion of the structure.The research may provide a reference for the design and development of miniature piezoelectric three-legged crawling robots.展开更多
Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused cra...Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused crawler which directly affects the search quality. This paper first introduces several traditional topic-specific crawling algorithms, then an inverse link based topic-specific crawling algorithm is put forward. Comparison experiment proves that this algorithm has a good performance in recall, obviously better than traditional Breadth-First and Shark-Search algorithms. The experiment also proves that this algorithm has a good precision.展开更多
Web crawlers have evolved from performing a meagre task of collecting statistics,security testing,web indexing and numerous other examples.The size and dynamism of the web are making crawling an interesting and challe...Web crawlers have evolved from performing a meagre task of collecting statistics,security testing,web indexing and numerous other examples.The size and dynamism of the web are making crawling an interesting and challenging task.Researchers have tackled various issues and challenges related to web crawling.One such issue is efficiently discovering hidden web data.Web crawler’s inability to work with form-based data,lack of benchmarks and standards for both performance measures and datasets for evaluation of the web crawlers make it still an immature research domain.The applications like vertical portals and data integration require hidden web crawling.Most of the existing methods are based on returning top k matches that makes exhaustive crawling difficult.The documents which are ranked high will be returned multiple times.The low ranked documents have slim chances of being retrieved.Discovering the hidden web sources and ranking them based on relevance is a core component of hidden web crawlers.The problem of ranking bias,heuristic approach and saturation of ranking algorithm led to low coverage.This research represents an enhanced ranking algorithm based on the triplet formula for prioritizing hidden websites to increase the coverage of the hidden web crawler.展开更多
Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature ...Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature and catalyst size are controlled. The data corroborate that it is possible to obtain clean vertical nanowire arrays while avoiding the crawling growth. 0% the other hand, crawling growth can be manipulated to obtain root-interconnected nanowire arrays, which could be useful for certain applications. Our results also imply that the previously suggested growth mechanism for the wire-on-wall hybridstructure might be incorrect. Finally, we show the formation of sub-millimeter long, straight ZnO nanowalls by combining a gold-catalyzed epitaxial growth of vertical nanowires and their mergence due to a confined crawling growth. These unconventional nanostructures might have unique electric or optical transport properties.展开更多
The indoor mould concentration depends not only on the outdoor mould source but also on the indoor mould source. The mould source is not only on the interior surface but also in the concealed spaces: a crawl space, a ...The indoor mould concentration depends not only on the outdoor mould source but also on the indoor mould source. The mould source is not only on the interior surface but also in the concealed spaces: a crawl space, a beam space, a wall cavity etc. Most detached houses in Japan have crawl spaces under the first floor. The humidity is high from spring to autumn in crawl spaces. Therefore the concentration of mould spore is very high in most crawl spaces. Prefabricated bathrooms called “bath-units” are installed in most Japanese houses. The authors showed in the previous studies that there are infiltration routes between bath-units and walls that the routes may lead chemical compounds from crawl space to indoor space. In this study, the influence of mould infiltration from crawl space upon indoor mould concentration is investigated using a test house which consists of a lavatory and a bathroom. The structure of the house is wooden post-and-beam. The house is airtight and insulated according to the latest building code for save energy. The mould concentrations were measured in the crawl space and the indoor spaces continuously using a mould multi-sampling system with a pump, valves and impingers. Before the measurements, the indoor mould concentration was made low using an air cleaner. The air flow rates were measured using tracer gases. After the exhaust fan was switched on, the mould concentration increased. The number of infiltrated mould was calculated using air flow rates and mould concentrations. The results showed that mould infiltration ratio may be one of the important indicators of indoor air quality.展开更多
Soft crawling robots have been widely studied and applied because of their excellent environmental adaptability and flexible movement.However,most existing soft crawling robots typically exhibit a single-motion mode a...Soft crawling robots have been widely studied and applied because of their excellent environmental adaptability and flexible movement.However,most existing soft crawling robots typically exhibit a single-motion mode and lack diverse capabilities.Inspired by Drosophila larvae,this paper proposes a compact soft crawling robot(weight,13 g;length,165 mm;diameter,35 mm)with multimodal locomotion(forward,turning,rolling,and twisting).Each robot module uses 4 sets of high-power-density shape memory alloy actuators,endowing it with 4 degrees of motion freedom.We analyze the mechanical characteristics of the robot modules through experiments and simulation analysis.The plug-and-play modules can be quickly assembled to meet different motion and task requirements.The soft crawling robot can be remotely operated with an external controller,showcasing multimodal motion on various material surfaces.In a narrow maze,the robot demonstrates agile movement and effective maneuvering around obstacles.In addition,leveraging the inherent bistable characteristics of the robot modules,we used the robot modules as anchoring units and installed a microcamera on the robot's head for pipeline detection.The robot completed the inspection in horizontal,vertical,curved,and branched pipelines,adjusted the camera view,and twisted a valve in the pipeline for the first time.Our research highlights the robot's superior locomotion and application capabilities,providing an innovative strategy for the development of lightweight,compact,and multifunctional soft crawling robots.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
基金supported by National Natural Science Foundation of China under Grant no.52475067.
文摘This paper presents an untethered pneumatic soft robot which can crawl both in horizontal and vertical pipes with different sizes and cross sections.This robot uses modular origami inspired soft-rigid hybrid actuator to produce telescoping and anchoring movements powered by vacuum pressure.The introduction of grooves to valley crease significantly lowers the full contraction vacuum pressure and improves the response,allowing the system can be driven by an onboard micro vacuum pump,enabling the possibility of miniaturization,integration,and untethered operation of the robot.A series of crawling experiments in pipes with different sizes and cross sections constructed by acrylic are conducted to validate the crawling performance of the robot.Within square cross-section pipes,the robot can achieve a velocity of 9.4 mm/s in horizontal crawling and 7.7 mm/s in vertical upward crawling.For horizontal crawling in circular pipes,it can reach a velocity of 8.0 mm/s.When fully charged,the robot can crawl for 40 min with a mileage of 16.649 m,which is sufficient for most drainage and industrial pipelines detection tasks.The robot demonstrates excellent endurance and speed performance that exceed most existing untethered soft pipe crawling robots.
基金supported by the National Natural Science Foundation of China(Nos.51375383).
文摘In this study,we present a small,integrated jumping-crawling robot capable of intermittent jumping and self-resetting.Compared to robots with a single mode of locomotion,this multi-modal robot exhibits enhanced obstacle-surmounting capabilities.To achieve this,the robot employs a novel combination of a jumping module and a crawling module.The jumping module features improved energy storage capacity and an active clutch.Within the constraints of structural robustness,the jumping module maximizes the explosive power of the linear spring by utilizing the mechanical advantage of a closed-loop mechanism and controls the energy flow of the jumping module through an active clutch mechanism.Furthermore,inspired by the limb movements of tortoises during crawling and self-righting,a single-degree-of-freedom spatial four-bar crawling mechanism was designed to enable crawling,steering,and resetting functions.To demonstrate its practicality,the integrated jumping-crawling robot was tested in a laboratory environment for functions such as jumping,crawling,self-resetting,and steering.Experimental results confirmed the feasibility of the proposed integrated jumping-crawling robot.
基金work is supported by the Fundamental Research Funds for the Central Universities(Grant No.B230205021)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(GrantNo.KYCX22_0592).The financial supports are gratefully acknowl-edged.
文摘A novel three-dimensional-fiber reinforced soft pneumatic actuator(3D-FRSPA)inspired by crab claw and human hand structure that can bend and deform independently in each segment is proposed.It has an omni-directional bending configuration,and the fibers twined symmetrically on both sides to improve the bending performance of FRSPA.In this paper,the static and kinematic analysis of 3D-FRSPA are carried out in detail.The effects of fiber,pneumatic chamber and segment length,and circular air chamber radius of 3D-FRSPA on the mechanical performance of the actuator are discussed,respectively.The soft mobile robot composed of 3D-FRSPA has the ability to crawl.Finally,the crawling processes of the soft mobile robot on different road conditions are studied,respectively,and the motion mechanism of the mobile actuator is shown.The numerical results show that the soft mobile robots have a good comprehensive performance,which verifies the correctness of the proposedmodel.This work shows that the proposed structures have great potential in complex road conditions,unknown space detection and other operations.
基金supported by the Research Program funded by the SeoulTech(Seoul National University of Science and Technology).
文摘This paper focuses on a newly developed transmission for a milli-scale eight-legged crawling robot called OriSCO.The transmission allows intuitive steering by directly changing the direction of the propulsion force.The transmission is based on the constrained spherical six-bar linkage.The constrained spherical six-bar linkage passes only reciprocating motion out of the motor’s rotating motion,allowing the crawling legs to kick the ground and obtain propulsion.Steering is achieved by adjusting the geometric constraints of the spherical six-bar using a servomotor,allowing the direction of propulsion to be changed.As a result,the OriSCO can move along the ground at a speed of 2.15 body lengths/s,and the robot is 60 mm long.
基金funded by Spanish‘Ministerio de Economía y Competitividad’‘Plan Nacional I+D+i 2008–2011(Project DEP DEP2011-29093)’and the“Fondo Europeo de Desarrollo Regional”(MICINN-FEDER)for supporting this project.
文摘Purpose To determine the association between lower-body strength and lower-body power capacities with sprint swimming performance in adolescent competitive swimmers.Methods A total of 44 front crawl swimmers(27 males and 17 females)performed anthropometric assessments,lower-body strength tests(half squat maximum isometric strength,dynamic half squat with 20,30 and 40%of the maximum isometric strength,and knee extension maximum isometric strength)and lower-body power tests(squat jump[SJ],countermovement jump[CMJ]and Abalakov jump).Further front crawl swimming best times in 50 and 100 m were recorded from official swimming competitions and front crawl technique was assessed by an experienced coach using a visual analogue scale.Results Swimming performance was correlated with lower-body power variables(SJ[r=−0.573 for 50 m and−0.642 for 100 m],CMJ[r=−0.497 for 50 m and−0.544 for 100 m],and Abalakov jump[r=−0.452 for 50 m and−0.415 for 100 m];p≤0.05)and lower-body strength(half squat maximum isometric strength[r=−0.430 for 50 m and−0.443 for 100 m];p≤0.05)in males but not in females.Further linear regression models showed that only lower-body power predicted both 50 m(Abalakov jump;r^(2)=0.58;change in r^(2)=0.18)and 100 m(SJ;r^(2)=0.66;change in r^(2)=0.15)performance in male swimmers.Conclusions This study emphasizes the greater association between lower-body power and sprint front crawl performance in adolescent males compared to females.Practical tests(i.e.,SJ and Abalakov jump)are shown to predict front crawl swimming performance,which may facilitate the performance control by coaches and trainers.
基金supported by the Research Fund for International Young Scientists of National Natural Science Foundation of China under Grant No.61550110248Tibet Autonomous Region Key Scientific Research Projects under Grant No.Z2014A18G2-13
文摘Abstract—Focused crawlers （also known as subjectoriented crawlers）, as the core part of vertical search engine, collect topic-specific web pages as many as they can to form a subject-oriented corpus for the latter data analyzing or user querying. This paper demonstrates that the popular algorithms utilized at the process of focused web crawling, basically refer to webpage analyzing algorithms and crawling strategies （prioritize the uniform resource locator （URLs） in the queue）. Advantages and disadvantages of three crawling strategies are shown in the first experiment, which indicates that the best-first search with an appropriate heuristics is a smart choice for topic-oriented crawlingwhile the depth-first search is helpless in focused crawling. Besides, another experiment on comparison of improved ones （with a webpage analyzing algorithm added） is carried out to verify that crawling strategies alone are not quite efficient for focused crawling and in most cases their mutual efforts are taken into consideration. In light of the experiment results and recent researches, some points on the research tendency of focused crawler algorithms are suggested.
基金Supported by the National Natural Science Foundation of China ( 51205209)
文摘In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driv- ing for the vehicle, a control strategy of the clutch was designed. The strategy increased the.slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was de- signed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.
基金supported by the National Natural Science Foundation of China (grant no.51505133)by Key Research Project in Colleges and Universities of Henan Province (23A460010)by Opening Project of Henan Engineering Laboratory of Photoelectric Sensor and Intelligent Measurement and Control,Henan Polytechnic University (grant no.HELPSIMC-2020-006).
文摘Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoelectric effect of piezoelectric ceramics was proposed.The three legs of the robot were equipped with piezoelectric bimorphs as drivers,respectively.The motion principles were analyzed and the overall force analysis was carried out with the theoretical mechanics method.The natural frequency,mode shape and amplitude were analyzed with simulation software COMSOL Multiphysics,the optimal size was determined through parametric analysis,and then the micro three-legged crawling robot was manufactured.The effects of different driving voltages,different driving frequencies,different motion bases and different loads on the motion speed of the robot were tested.It is shown that the maximum speed of single-leg driving was 35.41 cm/s,the switching ability between different motion directions was measured,and the movements in six different directions were achieved.It is demonstrated the feasibility of multi-directional motion of the structure.The research may provide a reference for the design and development of miniature piezoelectric three-legged crawling robots.
文摘Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused crawler which directly affects the search quality. This paper first introduces several traditional topic-specific crawling algorithms, then an inverse link based topic-specific crawling algorithm is put forward. Comparison experiment proves that this algorithm has a good performance in recall, obviously better than traditional Breadth-First and Shark-Search algorithms. The experiment also proves that this algorithm has a good precision.
基金Taif University Researchers Supporting Project number(TURSP-2020/98),Taif University,Taif,Saudi Arabia.
文摘Web crawlers have evolved from performing a meagre task of collecting statistics,security testing,web indexing and numerous other examples.The size and dynamism of the web are making crawling an interesting and challenging task.Researchers have tackled various issues and challenges related to web crawling.One such issue is efficiently discovering hidden web data.Web crawler’s inability to work with form-based data,lack of benchmarks and standards for both performance measures and datasets for evaluation of the web crawlers make it still an immature research domain.The applications like vertical portals and data integration require hidden web crawling.Most of the existing methods are based on returning top k matches that makes exhaustive crawling difficult.The documents which are ranked high will be returned multiple times.The low ranked documents have slim chances of being retrieved.Discovering the hidden web sources and ranking them based on relevance is a core component of hidden web crawlers.The problem of ranking bias,heuristic approach and saturation of ranking algorithm led to low coverage.This research represents an enhanced ranking algorithm based on the triplet formula for prioritizing hidden websites to increase the coverage of the hidden web crawler.
文摘Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature and catalyst size are controlled. The data corroborate that it is possible to obtain clean vertical nanowire arrays while avoiding the crawling growth. 0% the other hand, crawling growth can be manipulated to obtain root-interconnected nanowire arrays, which could be useful for certain applications. Our results also imply that the previously suggested growth mechanism for the wire-on-wall hybridstructure might be incorrect. Finally, we show the formation of sub-millimeter long, straight ZnO nanowalls by combining a gold-catalyzed epitaxial growth of vertical nanowires and their mergence due to a confined crawling growth. These unconventional nanostructures might have unique electric or optical transport properties.
文摘The indoor mould concentration depends not only on the outdoor mould source but also on the indoor mould source. The mould source is not only on the interior surface but also in the concealed spaces: a crawl space, a beam space, a wall cavity etc. Most detached houses in Japan have crawl spaces under the first floor. The humidity is high from spring to autumn in crawl spaces. Therefore the concentration of mould spore is very high in most crawl spaces. Prefabricated bathrooms called “bath-units” are installed in most Japanese houses. The authors showed in the previous studies that there are infiltration routes between bath-units and walls that the routes may lead chemical compounds from crawl space to indoor space. In this study, the influence of mould infiltration from crawl space upon indoor mould concentration is investigated using a test house which consists of a lavatory and a bathroom. The structure of the house is wooden post-and-beam. The house is airtight and insulated according to the latest building code for save energy. The mould concentrations were measured in the crawl space and the indoor spaces continuously using a mould multi-sampling system with a pump, valves and impingers. Before the measurements, the indoor mould concentration was made low using an air cleaner. The air flow rates were measured using tracer gases. After the exhaust fan was switched on, the mould concentration increased. The number of infiltrated mould was calculated using air flow rates and mould concentrations. The results showed that mould infiltration ratio may be one of the important indicators of indoor air quality.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LD22E-050007)National Natural Science Foundation of China(T2293724 and 62303407)the Key R&D Program of Zhejiang(2022C01022).
文摘Soft crawling robots have been widely studied and applied because of their excellent environmental adaptability and flexible movement.However,most existing soft crawling robots typically exhibit a single-motion mode and lack diverse capabilities.Inspired by Drosophila larvae,this paper proposes a compact soft crawling robot(weight,13 g;length,165 mm;diameter,35 mm)with multimodal locomotion(forward,turning,rolling,and twisting).Each robot module uses 4 sets of high-power-density shape memory alloy actuators,endowing it with 4 degrees of motion freedom.We analyze the mechanical characteristics of the robot modules through experiments and simulation analysis.The plug-and-play modules can be quickly assembled to meet different motion and task requirements.The soft crawling robot can be remotely operated with an external controller,showcasing multimodal motion on various material surfaces.In a narrow maze,the robot demonstrates agile movement and effective maneuvering around obstacles.In addition,leveraging the inherent bistable characteristics of the robot modules,we used the robot modules as anchoring units and installed a microcamera on the robot's head for pipeline detection.The robot completed the inspection in horizontal,vertical,curved,and branched pipelines,adjusted the camera view,and twisted a valve in the pipeline for the first time.Our research highlights the robot's superior locomotion and application capabilities,providing an innovative strategy for the development of lightweight,compact,and multifunctional soft crawling robots.
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.
