The main idea of reinforcement learning is evaluating the chosen action depending on the current reward.According to this concept,many algorithms achieved proper performance on classic Atari 2600 games.The main challe...The main idea of reinforcement learning is evaluating the chosen action depending on the current reward.According to this concept,many algorithms achieved proper performance on classic Atari 2600 games.The main challenge is when the reward is sparse or missing.Such environments are complex exploration environments likeMontezuma’s Revenge,Pitfall,and Private Eye games.Approaches built to deal with such challenges were very demanding.This work introduced a different reward system that enables the simple classical algorithm to learn fast and achieve high performance in hard exploration environments.Moreover,we added some simple enhancements to several hyperparameters,such as the number of actions and the sampling ratio that helped improve performance.We include the extra reward within the human demonstrations.After that,we used Prioritized Double Deep Q-Networks(Prioritized DDQN)to learning from these demonstrations.Our approach enabled the Prioritized DDQNwith a short learning time to finish the first level of Montezuma’s Revenge game and to perform well in both Pitfall and Private Eye.We used the same games to compare our results with several baselines,such as the Rainbow and Deep Q-learning from demonstrations(DQfD)algorithm.The results showed that the new rewards system enabled Prioritized DDQN to out-perform the baselines in the hard exploration games with short learning time.展开更多
This paper is a record of an interview discussion.It explains the demonstration process of the Three Gorges pro-ject in aspects of flood control and navigation,investment,settlement,sediment,ecological environment,geo...This paper is a record of an interview discussion.It explains the demonstration process of the Three Gorges pro-ject in aspects of flood control and navigation,investment,settlement,sediment,ecological environment,geological disasters,science and technology and democratic way of demonstration work.It shows clearly that the demonstra-tional conclusion is fully in conformity with the actual situation.展开更多
In this paper, we propose a new prediction from expert demonstration （PED） methodology to improve reliability and safety in tele-surgery. Data was collected from expert （clinician） demonstrations for the procedure...In this paper, we propose a new prediction from expert demonstration （PED） methodology to improve reliability and safety in tele-surgery. Data was collected from expert （clinician） demonstrations for the procedure of trocar insertion. We encoded a set of force, torque and penetration trajectories by using a Gaussian mixture model （GMM）. A generalization of these profiles and associated parameters were retrieved by Gaussian mixture regression （GMR）. We validated the proposed methodology for tele-robotic placement of the trocar in two stages. First, we tested the efficacy of the proposed PED approach for handling transmission error and latency. Our results showed that for the average case （12% packet error and 1070 loss of packet）, a 58.8~0 improvement in performance was obtained in comparison to using an extended Kalman filter. Next, we validated the methodology for surgical assistance on 15 participants. A haptic assistance mode was devised based on the proposed PED model to assist inexperienced operators to perform the procedure. The PED model was tested for instrument deviation, penetration force and penetration depth. Preliminary study results showed that participants with PED assistance performed the task with more consistency and exerted lesser penetration force than subjects without assistance.展开更多
Autonomous planning is a significant development direction of the space manipulator,and learning from demonstrations(LfD)is a potential strategy for complex tasks in the field.However,separating control from planning ...Autonomous planning is a significant development direction of the space manipulator,and learning from demonstrations(LfD)is a potential strategy for complex tasks in the field.However,separating control from planning may cause large torque fluctuations and energy consumptions,even instability or danger in control of space manipulators,especially for the planning based on the human demonstrations.Therefore,we present an autonomous planning and control strategy for space manipulators based on LfD and focus on the dynamics uncertainty problem,a common problem of actual manipulators.The process can be divided into three stages:firstly,we reproduced the stochastic directed trajectory based on the Gaussian process-based LfD;secondly,we built the model of the stochastic dynamics of the actual manipulator with Gaussian process;thirdly,we designed an optimal controller based on the dynamics model to obtain the improved commanded torques and trajectory,and used the separation theorem to deal with stochastic characteristics during control.We evaluated the strategy with locating pre-screwed bolts experiment by Tiangong-2 manipulator system on the ground.The result showed that,compared with other strategies,the strategy proposed in this paper could significantly reduce torque fluctuations and energy consumptions,and its precision can meet the task requirements.展开更多
In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, cont...In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, contrast, and width of the Fano resonance are analyzed. As the transmission coefficient of the capillary resonator increases, the absolute value of the slope of Fano resonances increases to reach its maximum, which is useful for sensors with an ultra-high sensitivity. There occurs another phenomenon of electromagnetically induced transparency when the reflectivity at the capillary–environment interface is close to 100%. We also experimentally demonstrated its capability for temperature and refractive index sensing, with a sensitivity of 10.9 pm∕°C and 431 d B∕RIU basedon the Fano resonance and the Lorentzian line shape, respectively.展开更多
In actor-critic reinforcement learning(RL)algorithms,function estimation errors are known to cause ineffective random exploration at the beginning of training,and lead to overestimated value estimates and suboptimal p...In actor-critic reinforcement learning(RL)algorithms,function estimation errors are known to cause ineffective random exploration at the beginning of training,and lead to overestimated value estimates and suboptimal policies.In this paper,we address the problem by executing advantage rectification with imperfect demonstrations,thus reducing the function estimation errors.Pretraining with expert demonstrations has been widely adopted to accelerate the learning process of deep reinforcement learning when simulations are expensive to obtain.However,existing methods,such as behavior cloning,often assume the demonstrations contain other information or labels with regard to performances,such as optimal assumption,which is usually incorrect and useless in the real world.In this paper,we explicitly handle imperfect demonstrations within the actor-critic RL frameworks,and propose a new method called learning from imperfect demonstrations with advantage rectification(LIDAR).LIDAR utilizes a rectified loss function to merely learn from selective demonstrations,which is derived from a minimal assumption that the demonstrating policies have better performances than our current policy.LIDAR learns from contradictions caused by estimation errors,and in turn reduces estimation errors.We apply LIDAR to three popular actor-critic algorithms,DDPG,TD3 and SAC,and experiments show that our method can observably reduce the function estimation errors,effectively leverage demonstrations far from the optimal,and outperform state-of-the-art baselines consistently in all the scenarios.展开更多
A research arena(WARA-PS)for sensing,data fusion,user interaction,planning and control of collaborative autonomous aerial and surface vehicles in public safety applications is presented.The objective is to demonstrate...A research arena(WARA-PS)for sensing,data fusion,user interaction,planning and control of collaborative autonomous aerial and surface vehicles in public safety applications is presented.The objective is to demonstrate scientific discoveries and to generate new directions for future research on autonomous systems for societal challenges.The enabler is a computational infrastructure with a core system architecture for industrial and academic collaboration.This includes a control and command system together with a framework for planning and executing tasks for unmanned surface vehicles and aerial vehicles.The motivating application for the demonstration is marine search and rescue operations.A state-of-art delegation framework for the mission planning together with three specific applications is also presented.The first one concerns model predictive control for cooperative rendezvous of autonomous unmanned aerial and surface vehicles.The second project is about learning to make safe real-time decisions under uncertainty for autonomous vehicles,and the third one is on robust terrain-aided navigation through sensor fusion and virtual reality tele-operation to support a GPS-free positioning system in marine environments.The research results have been experimentally evaluated and demonstrated to industry and public sector audiences at a marine test facility.It would be most difficult to do experiments on this large scale without the WARA-PS research arena.Furthermore,these demonstrator activities have resulted in effective research dissemination with high public visibility,business impact and new research collaborations between academia and industry.展开更多
CT:As the first ITMA ASIA+CITME exhibition held in Singapore,what are the highlights of this show?Are there any activities planned for the exhibition?Charles Beauduin:The first combined exhibition in Singapore will fe...CT:As the first ITMA ASIA+CITME exhibition held in Singapore,what are the highlights of this show?Are there any activities planned for the exhibition?Charles Beauduin:The first combined exhibition in Singapore will feature the unique selling proposition of an ITMA exhibition,such as live machinery demonstrations,and exhibits clustered in product sectors.As it is only a four-day exhibition,our exhibitors would like to concentrate on business and to present their technologies and solutions to the region’s buyers who don’t visit our Europe or China exhibitions.There is a highlight which will add value to our participants’experience-The ITMA Sustainability Forum which is presented by CEMATEX on the third day of the exhibition.展开更多
The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In ...The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.展开更多
Founded in 1993,Zhejiang Rifa Textile Machinery Co.,Ltd.is a national key high-tech enterprise,a leading enterprise in China’s machinery industry,a CIMS engineering demonstration enterprise under the 863 Program,a na...Founded in 1993,Zhejiang Rifa Textile Machinery Co.,Ltd.is a national key high-tech enterprise,a leading enterprise in China’s machinery industry,a CIMS engineering demonstration enterprise under the 863 Program,a national CAD application engineering demonstration enterprise,a hightech enterprise of the National Torch Plan,and a vice president unit of the China Textile Machinery Association.It currently runs three subsidiaries,namely,Shandong Rifa Textile Machinery Co.,Ltd.,Anhui Rifa Textile Machinery Co.,Ltd.and Zhejiang Rifa Textile Machinery Tech Co.,Ltd.展开更多
The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,wo...The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.展开更多
[Objectives]To address the weeding challenges within the corn and soybean strip intercropping field and identify appropriate herbicide types and application methods suitable for the corn and soybean strip intercroppin...[Objectives]To address the weeding challenges within the corn and soybean strip intercropping field and identify appropriate herbicide types and application methods suitable for the corn and soybean strip intercropping fields in Siyang County.[Methods]The trial comprised six herbicide treatments and one blank control,with investigations conducted to assess efficacy,safety,and yield.[Results]Each herbicide treatment effectively controlled weeds,demonstrated high safety,and enhanced the yields of both soybeans and corn.The combined application of soil sealing with stem and leaf spray exhibited superior overall weed control compared to soil sealing alone.At 28 d following stem and leaf spray,the plant control effect and fresh weight control effect against weeds in the combined treatment of soil sealing with stem and leaf spray all exceeded 89%.[Conclusions]This study offers technical support for advancing the practice of strip intercropping between corn and soybeans.展开更多
IntuiGrasp is a novel three-fingered dexterous hand that pioneers bio-inspired demonstrations with intuitive priors(BDIP)to bridge the gap between human tactile intuition and robotic execution.Unlike conven-tional pro...IntuiGrasp is a novel three-fingered dexterous hand that pioneers bio-inspired demonstrations with intuitive priors(BDIP)to bridge the gap between human tactile intuition and robotic execution.Unlike conven-tional programming,BDIP leverages human's innate priors(e.g.,“A pack of tissues requires gentle grasps,cups demand firm contact”)by enabling real-time transfer of gesture and force policies during physical demon-stration.When a human demonstrator wears IntuiGrasp,driven rings provide real-time haptic feedback on contact stress and slip,while inte-grated tactile sensors translate these human policies into image data,offering valuable data for imitation learning.In this study,human teachers use IntuiGrasp to demonstrate how to grasp three types of objects:a cup,a crumpled tissue pack,and a thin playing card.IntuiGrasp translates the policies for grasping these objects into image information that describes tactile sensations in real time.展开更多
Under the blazing sun of Kamuli District in Uganda’s Eastern Region,a group of young farmers gathered around a patch of freshly turned red soil.Cameras rolled as Uganda’s First Deputy Prime Minister Rebecca Kadaga j...Under the blazing sun of Kamuli District in Uganda’s Eastern Region,a group of young farmers gathered around a patch of freshly turned red soil.Cameras rolled as Uganda’s First Deputy Prime Minister Rebecca Kadaga joined local youth to plant the first chilli seedlings on a 10-acre(4.05 hectares)demonstration farm.The live broadcast,aired on the national agricultural television programme Kungula,marked not only the launch of a digital farming project led by AMPA Media,but also symbolised Africa’s growing ambition to unite tradition with technology.展开更多
The diffusion of industrial robot technology has coincided with increasing divergence in firms’market shares,potentially leading to enhanced market power and shifts in the distribution of factor income.This paper inv...The diffusion of industrial robot technology has coincided with increasing divergence in firms’market shares,potentially leading to enhanced market power and shifts in the distribution of factor income.This paper investigates the impact of industrial robot adoption on firms’labor income share and explores the underlying mechanisms,with particular attention to the rise of superstar firms.The findings suggest that,overall,the use of industrial robots contributes to an increase in labor’s income share,reflecting a generally favorable trend for labor’s position in primary income distribution.This effect,however,is markedly heterogeneous across different types of firms,regions,and industries.A significant concern is that robot adoption strengthens firms’relative market power within industries,fueling the emergence of superstar firms.These firms jointly influence labor income share through both a competition effect and a demonstration effect:the former is the main cause of declining labor shares,while the latter introduces a new channel through which labor’s share is further reduced.Although antitrust policies can help improve labor’s income share,they are not well-suited to curbing the market power expansion driven by industrial robot adoption.Thus,the concern over superstar firms’suppression of labor income remains.Amid the intensifying trend of“machines replacing humans”,this paper offers empirical insights into how to address the distributional implications brought about by the rise of superstar firms.展开更多
Within the context of the"Window of Qingtian"initiative for constructing beautiful countryside in the new era,this study focuses on Malingjiao Village in Zhenbu Town,Qingtian County,exploring innovative appr...Within the context of the"Window of Qingtian"initiative for constructing beautiful countryside in the new era,this study focuses on Malingjiao Village in Zhenbu Town,Qingtian County,exploring innovative approaches and practical models for rural revitalization in mountainous areas.By employing a combination of field research,policy analysis,and case studies,this research deeply analyzes the specific measures implemented in Malingjiao Village,including infrastructure enhancement,integration of primary,secondary,and tertiary industries,revitalization of collective assets,ecological conservation,and cultural heritage preservation.The results indicate that,by pursuing strategies of shared prosperity,agricultural-tourism integration,and integrated development of primary,secondary,and tertiary industries,the village has successfully optimized its industrial structure,expanded the collective economy,increased villager incomes,and improved the ecological environment.This study not only provides a referential demonstration model for beautiful countryside construction throughout Qingtian County but also offers empirical and theoretical support for rural revitalization in mountainous regions across southwestern Zhejiang and even the entire province.展开更多
Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and acce...Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and accessibility.Compared with summer tourism and vacation tourism,summer residential tourism had got less attention and lacks in prospective and preventive research.Hence,this study focused on potential assessment,pattern recognition and phase segmentation of 32 residential tourism destinations in China selected from 4 lists.An index system of 16 indicators from 5 dimensions was established as Summer Residence Index(SRI),and Range method,Entropy weight method and Composite index method were chosen as the core methods.Three main conclusions were as follows.(1)Only 2 typical districts’SRI value were near to 0.6,and 4 destinations were below 0.1,about 26 destinations were at medium-level,which indicated that China’s summer residential tourism was not so popular and only few destinations have stepped into a higher level.(2)Seven patterns could be recognized based on the contribution of the 5 dimensions to SRI value,including 3 single-factor driven patterns and 4 compound factors driven patterns.(3)Like tourist area life cycle(TALC),Unconscious stage,Initial stage,Developmental stage and Maturity stage could be segmented for summer residential destinations with the value of below 0.1,0.1-0.3,0.3-0.5,and above 0.5.Four destinations were under Unconscious stage.Twenty-two destinations were at initiate stage.Only 4 destinations have stepped into development stage and 2 at maturity stage.China’summer residential tourism has just started and has a better prospect.This study is just an attempt and needs further consideration,for example,a tracking study of SRI calculation for each year will be carried to justify the effectiveness of SRI and to check the rationality of the empirical results.As time goes on,policies in housing,residential estate and other aspects should be included as a factor in the SRI index.Data availability should be optimized because of better data sources and new technologies.Some other districts or cities in 2 batches of national Comprehensive Tourism Demonstration Zones(CTDZs)pilots and provincial CTDZs will be further selections of summer residential tourism destinations.展开更多
词汇习得研究是语料库语言学界的研究热点,作为语料库驱动的短语研究的重要描述机制,扩展意义单位模型为研究词汇的整体性意义提供了新的研究视角。本研究利用美国当代英语语料库(COCA),以动词“demonstrate”为节点词,探讨了该词的扩...词汇习得研究是语料库语言学界的研究热点,作为语料库驱动的短语研究的重要描述机制,扩展意义单位模型为研究词汇的整体性意义提供了新的研究视角。本研究利用美国当代英语语料库(COCA),以动词“demonstrate”为节点词,探讨了该词的扩展意义单位,即该动词的搭配、类联接特点、搭配词的语义倾向,以及整个复合词项的语义韵信息。研究发现,动词“demonstrate”常出现在学术文章中,常与带有“研究”词义的词汇搭配,多用于书面语。同时,该词能够与名词、形容词、副词和介词等词性进行不同的类联接,从而构成丰富多样的句法结构。此外,该词与形容词、副词和介词搭配时,分别体现积极、中性和消极的语义倾向,整个复合词项分别呈现出褒义、中立和贬义的语义韵。通过研究词汇的扩展意义单位,二语学习者可以发现整个扩展意义单位所传达的态度意义,从而提高自身的语言表达能力。The study of vocabulary acquisition has become a hot topic in the corpus linguistics community. As an important descriptive mechanism for corpus-driven phrase research, the extended unit of meaning model provides a new research perspective on the holistic meaning of vocabulary. This study utilizes the Corpus of Contemporary American English (COCA) to investigate the extended unit of meaning of the verb “demonstrate”. This includes its collocation, colligation, semantic preference and semantic prosody. The results of the study indicate that the verb “demonstrate” frequently appears in academic articles, often collocates with words carrying the meaning of research, and is predominantly used in written language. Furthermore, this verb is able to form various syntactic structures through different collocations with nouns, adjectives, adverbs, and prepositions. Additionally, when collocating with adjectives, adverbs, and prepositions, the verb exhibits positive, neutral, and negative semantic preferences, respectively, resulting in a positive, neutral, and negative semantic prosody. By studying the expanded semantic units of vocabulary, second language learners can uncover the attitudinal meanings conveyed by the extended unit of meaning, thereby enhancing their own language expression abilities.展开更多
To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflectio...To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflection-intelligent reflecting surface(STAR-IRS),has been proposed in this work.A Harris Hawks optimizer algorithm(HHOA)-based two-stage alternating iteration algorithm(TSAIA)is presented to jointly optimize the magnitude and uniformity of the received optical power.Besides,to demonstrate the superiority of the proposed strategy,several benchmark schemes are simulated and compared.Results showed that compared to other optimization strategies,the TSAIA scheme is more capable of balancing the average value and variance of the received optical power,when the maximal ratio combining(MRC)strategy is adopted at the receiver.Moreover,as the number of the STAR-IRS elements increases,the optical power variance of the system optimized by TSAIA scheme would become smaller while the average optical power would get larger.This study will benefit the design of received optical power distribution for indoor VLC systems.展开更多
The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic pe...The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.展开更多
文摘The main idea of reinforcement learning is evaluating the chosen action depending on the current reward.According to this concept,many algorithms achieved proper performance on classic Atari 2600 games.The main challenge is when the reward is sparse or missing.Such environments are complex exploration environments likeMontezuma’s Revenge,Pitfall,and Private Eye games.Approaches built to deal with such challenges were very demanding.This work introduced a different reward system that enables the simple classical algorithm to learn fast and achieve high performance in hard exploration environments.Moreover,we added some simple enhancements to several hyperparameters,such as the number of actions and the sampling ratio that helped improve performance.We include the extra reward within the human demonstrations.After that,we used Prioritized Double Deep Q-Networks(Prioritized DDQN)to learning from these demonstrations.Our approach enabled the Prioritized DDQNwith a short learning time to finish the first level of Montezuma’s Revenge game and to perform well in both Pitfall and Private Eye.We used the same games to compare our results with several baselines,such as the Rainbow and Deep Q-learning from demonstrations(DQfD)algorithm.The results showed that the new rewards system enabled Prioritized DDQN to out-perform the baselines in the hard exploration games with short learning time.
文摘This paper is a record of an interview discussion.It explains the demonstration process of the Three Gorges pro-ject in aspects of flood control and navigation,investment,settlement,sediment,ecological environment,geological disasters,science and technology and democratic way of demonstration work.It shows clearly that the demonstra-tional conclusion is fully in conformity with the actual situation.
基金supported in part by the"Juan de la Cierva"Spanish Program
文摘In this paper, we propose a new prediction from expert demonstration （PED） methodology to improve reliability and safety in tele-surgery. Data was collected from expert （clinician） demonstrations for the procedure of trocar insertion. We encoded a set of force, torque and penetration trajectories by using a Gaussian mixture model （GMM）. A generalization of these profiles and associated parameters were retrieved by Gaussian mixture regression （GMR）. We validated the proposed methodology for tele-robotic placement of the trocar in two stages. First, we tested the efficacy of the proposed PED approach for handling transmission error and latency. Our results showed that for the average case （12% packet error and 1070 loss of packet）, a 58.8~0 improvement in performance was obtained in comparison to using an extended Kalman filter. Next, we validated the methodology for surgical assistance on 15 participants. A haptic assistance mode was devised based on the proposed PED model to assist inexperienced operators to perform the procedure. The PED model was tested for instrument deviation, penetration force and penetration depth. Preliminary study results showed that participants with PED assistance performed the task with more consistency and exerted lesser penetration force than subjects without assistance.
基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.51521003)the National Natural Science Foundation of China(Grant No.61803124)the Post-doctor Research Startup Foundation of Heilongjiang Province。
文摘Autonomous planning is a significant development direction of the space manipulator,and learning from demonstrations(LfD)is a potential strategy for complex tasks in the field.However,separating control from planning may cause large torque fluctuations and energy consumptions,even instability or danger in control of space manipulators,especially for the planning based on the human demonstrations.Therefore,we present an autonomous planning and control strategy for space manipulators based on LfD and focus on the dynamics uncertainty problem,a common problem of actual manipulators.The process can be divided into three stages:firstly,we reproduced the stochastic directed trajectory based on the Gaussian process-based LfD;secondly,we built the model of the stochastic dynamics of the actual manipulator with Gaussian process;thirdly,we designed an optimal controller based on the dynamics model to obtain the improved commanded torques and trajectory,and used the separation theorem to deal with stochastic characteristics during control.We evaluated the strategy with locating pre-screwed bolts experiment by Tiangong-2 manipulator system on the ground.The result showed that,compared with other strategies,the strategy proposed in this paper could significantly reduce torque fluctuations and energy consumptions,and its precision can meet the task requirements.
基金National Natural Science Foundation of China(NSFC)(61377081,61675126)
文摘In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, contrast, and width of the Fano resonance are analyzed. As the transmission coefficient of the capillary resonator increases, the absolute value of the slope of Fano resonances increases to reach its maximum, which is useful for sensors with an ultra-high sensitivity. There occurs another phenomenon of electromagnetically induced transparency when the reflectivity at the capillary–environment interface is close to 100%. We also experimentally demonstrated its capability for temperature and refractive index sensing, with a sensitivity of 10.9 pm∕°C and 431 d B∕RIU basedon the Fano resonance and the Lorentzian line shape, respectively.
基金This work was supported by the National Key R&D Plan(2016YFB0100901)the National Natural Science Foundation of China(Grant Nos.U20B2062&61673237)the Beijing Municipal Science&Technology Project(Z191100007419001).
文摘In actor-critic reinforcement learning(RL)algorithms,function estimation errors are known to cause ineffective random exploration at the beginning of training,and lead to overestimated value estimates and suboptimal policies.In this paper,we address the problem by executing advantage rectification with imperfect demonstrations,thus reducing the function estimation errors.Pretraining with expert demonstrations has been widely adopted to accelerate the learning process of deep reinforcement learning when simulations are expensive to obtain.However,existing methods,such as behavior cloning,often assume the demonstrations contain other information or labels with regard to performances,such as optimal assumption,which is usually incorrect and useless in the real world.In this paper,we explicitly handle imperfect demonstrations within the actor-critic RL frameworks,and propose a new method called learning from imperfect demonstrations with advantage rectification(LIDAR).LIDAR utilizes a rectified loss function to merely learn from selective demonstrations,which is derived from a minimal assumption that the demonstrating policies have better performances than our current policy.LIDAR learns from contradictions caused by estimation errors,and in turn reduces estimation errors.We apply LIDAR to three popular actor-critic algorithms,DDPG,TD3 and SAC,and experiments show that our method can observably reduce the function estimation errors,effectively leverage demonstrations far from the optimal,and outperform state-of-the-art baselines consistently in all the scenarios.
基金All authors are partially supported by the Wallenberg AI,Autonomous Systems and Software Program(WASP)funded by the Knut and Alice Wallenberg Foundation.The first and second authors are additionally supported by the ELLIIT Network Organization for Information and Communication Technology,Swedenthe Swedish Foundation for Strategic Research SSF(Smart Systems Project RIT15-0097)+1 种基金The second author is also supported by a RExperts Program Grant 2020A1313030098 from the Guangdong Department of Science and Technology,ChinaThe fifth and eighth authors are additionally supported by the Swedish Research Council.
文摘A research arena(WARA-PS)for sensing,data fusion,user interaction,planning and control of collaborative autonomous aerial and surface vehicles in public safety applications is presented.The objective is to demonstrate scientific discoveries and to generate new directions for future research on autonomous systems for societal challenges.The enabler is a computational infrastructure with a core system architecture for industrial and academic collaboration.This includes a control and command system together with a framework for planning and executing tasks for unmanned surface vehicles and aerial vehicles.The motivating application for the demonstration is marine search and rescue operations.A state-of-art delegation framework for the mission planning together with three specific applications is also presented.The first one concerns model predictive control for cooperative rendezvous of autonomous unmanned aerial and surface vehicles.The second project is about learning to make safe real-time decisions under uncertainty for autonomous vehicles,and the third one is on robust terrain-aided navigation through sensor fusion and virtual reality tele-operation to support a GPS-free positioning system in marine environments.The research results have been experimentally evaluated and demonstrated to industry and public sector audiences at a marine test facility.It would be most difficult to do experiments on this large scale without the WARA-PS research arena.Furthermore,these demonstrator activities have resulted in effective research dissemination with high public visibility,business impact and new research collaborations between academia and industry.
文摘CT:As the first ITMA ASIA+CITME exhibition held in Singapore,what are the highlights of this show?Are there any activities planned for the exhibition?Charles Beauduin:The first combined exhibition in Singapore will feature the unique selling proposition of an ITMA exhibition,such as live machinery demonstrations,and exhibits clustered in product sectors.As it is only a four-day exhibition,our exhibitors would like to concentrate on business and to present their technologies and solutions to the region’s buyers who don’t visit our Europe or China exhibitions.There is a highlight which will add value to our participants’experience-The ITMA Sustainability Forum which is presented by CEMATEX on the third day of the exhibition.
基金co-supported by the National Natural Science Foundation of China(No.12372045)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023B1515120018)the Shenzhen Science and Technology Program,China(No.JCYJ20220818102207015).
文摘The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.
文摘Founded in 1993,Zhejiang Rifa Textile Machinery Co.,Ltd.is a national key high-tech enterprise,a leading enterprise in China’s machinery industry,a CIMS engineering demonstration enterprise under the 863 Program,a national CAD application engineering demonstration enterprise,a hightech enterprise of the National Torch Plan,and a vice president unit of the China Textile Machinery Association.It currently runs three subsidiaries,namely,Shandong Rifa Textile Machinery Co.,Ltd.,Anhui Rifa Textile Machinery Co.,Ltd.and Zhejiang Rifa Textile Machinery Tech Co.,Ltd.
基金Supported by 2025 Gansu Provincial Party School(Institute of Administration)System Social Science Planning Project(QSDXYB2025046).
文摘The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.
文摘[Objectives]To address the weeding challenges within the corn and soybean strip intercropping field and identify appropriate herbicide types and application methods suitable for the corn and soybean strip intercropping fields in Siyang County.[Methods]The trial comprised six herbicide treatments and one blank control,with investigations conducted to assess efficacy,safety,and yield.[Results]Each herbicide treatment effectively controlled weeds,demonstrated high safety,and enhanced the yields of both soybeans and corn.The combined application of soil sealing with stem and leaf spray exhibited superior overall weed control compared to soil sealing alone.At 28 d following stem and leaf spray,the plant control effect and fresh weight control effect against weeds in the combined treatment of soil sealing with stem and leaf spray all exceeded 89%.[Conclusions]This study offers technical support for advancing the practice of strip intercropping between corn and soybeans.
文摘IntuiGrasp is a novel three-fingered dexterous hand that pioneers bio-inspired demonstrations with intuitive priors(BDIP)to bridge the gap between human tactile intuition and robotic execution.Unlike conven-tional programming,BDIP leverages human's innate priors(e.g.,“A pack of tissues requires gentle grasps,cups demand firm contact”)by enabling real-time transfer of gesture and force policies during physical demon-stration.When a human demonstrator wears IntuiGrasp,driven rings provide real-time haptic feedback on contact stress and slip,while inte-grated tactile sensors translate these human policies into image data,offering valuable data for imitation learning.In this study,human teachers use IntuiGrasp to demonstrate how to grasp three types of objects:a cup,a crumpled tissue pack,and a thin playing card.IntuiGrasp translates the policies for grasping these objects into image information that describes tactile sensations in real time.
文摘Under the blazing sun of Kamuli District in Uganda’s Eastern Region,a group of young farmers gathered around a patch of freshly turned red soil.Cameras rolled as Uganda’s First Deputy Prime Minister Rebecca Kadaga joined local youth to plant the first chilli seedlings on a 10-acre(4.05 hectares)demonstration farm.The live broadcast,aired on the national agricultural television programme Kungula,marked not only the launch of a digital farming project led by AMPA Media,but also symbolised Africa’s growing ambition to unite tradition with technology.
基金supported by General Project of the National Social Science Fund of China(NSSFC),“Mechanisms and Strategies of Artificial Intelligence’s Impact on Inter-firm Wage Disparities”(Grant No.21BJY097).
文摘The diffusion of industrial robot technology has coincided with increasing divergence in firms’market shares,potentially leading to enhanced market power and shifts in the distribution of factor income.This paper investigates the impact of industrial robot adoption on firms’labor income share and explores the underlying mechanisms,with particular attention to the rise of superstar firms.The findings suggest that,overall,the use of industrial robots contributes to an increase in labor’s income share,reflecting a generally favorable trend for labor’s position in primary income distribution.This effect,however,is markedly heterogeneous across different types of firms,regions,and industries.A significant concern is that robot adoption strengthens firms’relative market power within industries,fueling the emergence of superstar firms.These firms jointly influence labor income share through both a competition effect and a demonstration effect:the former is the main cause of declining labor shares,while the latter introduces a new channel through which labor’s share is further reduced.Although antitrust policies can help improve labor’s income share,they are not well-suited to curbing the market power expansion driven by industrial robot adoption.Thus,the concern over superstar firms’suppression of labor income remains.Amid the intensifying trend of“machines replacing humans”,this paper offers empirical insights into how to address the distributional implications brought about by the rise of superstar firms.
基金Basic Scientific Research Operating Funds Program for Provincial Higher Education Institutions of Zhejiang College of Construction.
文摘Within the context of the"Window of Qingtian"initiative for constructing beautiful countryside in the new era,this study focuses on Malingjiao Village in Zhenbu Town,Qingtian County,exploring innovative approaches and practical models for rural revitalization in mountainous areas.By employing a combination of field research,policy analysis,and case studies,this research deeply analyzes the specific measures implemented in Malingjiao Village,including infrastructure enhancement,integration of primary,secondary,and tertiary industries,revitalization of collective assets,ecological conservation,and cultural heritage preservation.The results indicate that,by pursuing strategies of shared prosperity,agricultural-tourism integration,and integrated development of primary,secondary,and tertiary industries,the village has successfully optimized its industrial structure,expanded the collective economy,increased villager incomes,and improved the ecological environment.This study not only provides a referential demonstration model for beautiful countryside construction throughout Qingtian County but also offers empirical and theoretical support for rural revitalization in mountainous regions across southwestern Zhejiang and even the entire province.
基金Supported by Ningxia Natural Science Foundation(2024AAC03100).
文摘Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and accessibility.Compared with summer tourism and vacation tourism,summer residential tourism had got less attention and lacks in prospective and preventive research.Hence,this study focused on potential assessment,pattern recognition and phase segmentation of 32 residential tourism destinations in China selected from 4 lists.An index system of 16 indicators from 5 dimensions was established as Summer Residence Index(SRI),and Range method,Entropy weight method and Composite index method were chosen as the core methods.Three main conclusions were as follows.(1)Only 2 typical districts’SRI value were near to 0.6,and 4 destinations were below 0.1,about 26 destinations were at medium-level,which indicated that China’s summer residential tourism was not so popular and only few destinations have stepped into a higher level.(2)Seven patterns could be recognized based on the contribution of the 5 dimensions to SRI value,including 3 single-factor driven patterns and 4 compound factors driven patterns.(3)Like tourist area life cycle(TALC),Unconscious stage,Initial stage,Developmental stage and Maturity stage could be segmented for summer residential destinations with the value of below 0.1,0.1-0.3,0.3-0.5,and above 0.5.Four destinations were under Unconscious stage.Twenty-two destinations were at initiate stage.Only 4 destinations have stepped into development stage and 2 at maturity stage.China’summer residential tourism has just started and has a better prospect.This study is just an attempt and needs further consideration,for example,a tracking study of SRI calculation for each year will be carried to justify the effectiveness of SRI and to check the rationality of the empirical results.As time goes on,policies in housing,residential estate and other aspects should be included as a factor in the SRI index.Data availability should be optimized because of better data sources and new technologies.Some other districts or cities in 2 batches of national Comprehensive Tourism Demonstration Zones(CTDZs)pilots and provincial CTDZs will be further selections of summer residential tourism destinations.
文摘词汇习得研究是语料库语言学界的研究热点,作为语料库驱动的短语研究的重要描述机制,扩展意义单位模型为研究词汇的整体性意义提供了新的研究视角。本研究利用美国当代英语语料库(COCA),以动词“demonstrate”为节点词,探讨了该词的扩展意义单位,即该动词的搭配、类联接特点、搭配词的语义倾向,以及整个复合词项的语义韵信息。研究发现,动词“demonstrate”常出现在学术文章中,常与带有“研究”词义的词汇搭配,多用于书面语。同时,该词能够与名词、形容词、副词和介词等词性进行不同的类联接,从而构成丰富多样的句法结构。此外,该词与形容词、副词和介词搭配时,分别体现积极、中性和消极的语义倾向,整个复合词项分别呈现出褒义、中立和贬义的语义韵。通过研究词汇的扩展意义单位,二语学习者可以发现整个扩展意义单位所传达的态度意义,从而提高自身的语言表达能力。The study of vocabulary acquisition has become a hot topic in the corpus linguistics community. As an important descriptive mechanism for corpus-driven phrase research, the extended unit of meaning model provides a new research perspective on the holistic meaning of vocabulary. This study utilizes the Corpus of Contemporary American English (COCA) to investigate the extended unit of meaning of the verb “demonstrate”. This includes its collocation, colligation, semantic preference and semantic prosody. The results of the study indicate that the verb “demonstrate” frequently appears in academic articles, often collocates with words carrying the meaning of research, and is predominantly used in written language. Furthermore, this verb is able to form various syntactic structures through different collocations with nouns, adjectives, adverbs, and prepositions. Additionally, when collocating with adjectives, adverbs, and prepositions, the verb exhibits positive, neutral, and negative semantic preferences, respectively, resulting in a positive, neutral, and negative semantic prosody. By studying the expanded semantic units of vocabulary, second language learners can uncover the attitudinal meanings conveyed by the extended unit of meaning, thereby enhancing their own language expression abilities.
基金supported by the National Natural Science Foundation of China(No.62071365)the Key Research and Development Program of Shaanxi Province(No.2017ZDCXL-GY-06-02).
文摘To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflection-intelligent reflecting surface(STAR-IRS),has been proposed in this work.A Harris Hawks optimizer algorithm(HHOA)-based two-stage alternating iteration algorithm(TSAIA)is presented to jointly optimize the magnitude and uniformity of the received optical power.Besides,to demonstrate the superiority of the proposed strategy,several benchmark schemes are simulated and compared.Results showed that compared to other optimization strategies,the TSAIA scheme is more capable of balancing the average value and variance of the received optical power,when the maximal ratio combining(MRC)strategy is adopted at the receiver.Moreover,as the number of the STAR-IRS elements increases,the optical power variance of the system optimized by TSAIA scheme would become smaller while the average optical power would get larger.This study will benefit the design of received optical power distribution for indoor VLC systems.
基金Supported by " Research on The Control Technology of Subtropical Agriculture Pollution System" Special Project of National Environment Protection Public Welfare Industry Science Research "Research on The Construction Strategy of Ecological Civilization" Development Plan Research Project of State Development and Reform Commission+1 种基金Xiangxiang " High-output and Efficient Cultivation of High Quality Rice and Processing Technology Industrialization Demonstration " in The Plan Test Site of National Science and Technology Enriching People and Developing County Special Project Action" Xiangxiang Middle and Long-term Development Plan of Modern Agriculture" of Subtropical Agriculture Ecology Institute in Chinese Academy of Science
文摘The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.
