Imminent abortion needs more serious attention since it remains a big problem in Indonesia considering its epidemiology, morbidity, mortality,?and prognosis. In fact, some cases can still be prevented.?The objective o...Imminent abortion needs more serious attention since it remains a big problem in Indonesia considering its epidemiology, morbidity, mortality,?and prognosis. In fact, some cases can still be prevented.?The objective of this study was to determine pathogenesis, diagnosis,?and prognosis of imminent abortion through the role of antioxidant vitamin C in the interaction of superoxide dismutase (SOD), interferon-γ?(IFN-γ), interleukin-4 (IL-4), vascular cells adhesion molecule-1?(VCAM-1), and decidual spiral artery resistance index (DSA RI).?This study took 10 months from March to December 2007 at Obstetrics and Gynecology Department of Medical Faculty of?Padjadjaran?University/Hasan Sadikin Hospital, Bandung. Sixty pregnant women who met the inclusion and exclusion criteria were divided into two groups with the random clinical trial method, double-blind with?repeated measurements.?Data were analyzed statistically using t test, Mann-Whitney, Rank?Spearman, Wilcoxon, t paired, and diagnostic test.?The results of this study showed that the incidence of abortion in vitamin C group was 9 cases (30%) and placebo group was 13 cases (43.3%). There was a significant difference in SOD, IFN-γ, IL-4 and VCAM-1 level between groups of women with and without abortion (p < 0.001).?There was a significant difference of SOD level between women with abortion 655.8 (163.6) U/gHb and placebo group 824.5 (106.7) U/gHb after vitamin C administration (p = 0.008). The cutoff point of SOD?was?￡992 U/gHbwhich?showed quite high sensitivity, specificity, accuracy,?and significant difference (p < 0.001). The cutoff point abortion of DSA resistance index was ≥0.55 with 45% accuracy (p = 0.002). The highest change of IL-4 level was 60.7% in vitamin C group and VCAM-1 was?-2.2% (p < 0.05) after?vitamin C administration. There was a negative correlation in SOD changes toward IL-4 changes after vitamin C administration (r =?-0.523) (p = 0.003), a positive correlation between SOD changes and IL-4 changes (0.597) (p < 0.001), a negative correlation between SOD changes and VCAM-1 changes (r =?-0.737) (p < 0.001) and a negative correlation between SOD changes and DSA RI changes (r =?-0.208) (p = 0.022). There were significant changes in the increment of IL-4 and SOD level (p < 0.001) and a decline in IFN-γ, VCAM-1 and DSA RI (p < 0.001) before and after vitamin C administration. In conclusion, there?was a correlation between the?increase of SOD level with?the?decrease of INF-γ?level and?the?increase of IL-4 level in imminent abortion after vitamin C administration. There?was a correlation between?the?increase of SOD level with?the?decrease of DSA RI and?the?decrease of VCAM-1 level in imminent abortion after vitamin C administration. In abortion, there?was?a?decrease of SOD and IL-4 level,?as well as an?increase of IFN-γ, VCAM-1, and DSA RI level.展开更多
Lower-income countries face a persistent challenge:innovation activities tend to concentrate in more developed regions.Existing research offers limited solutions,often emphasizing local advantages or frugal innovation...Lower-income countries face a persistent challenge:innovation activities tend to concentrate in more developed regions.Existing research offers limited solutions,often emphasizing local advantages or frugal innovation to reduce regional disparities.This study challenges the conventional approach of competing with advanced economies and proposes an"integrative"strategy that treats innovation as a multifaceted process encompassing diverse activities.Building on Capello and Lenzi's(2014)distinction between innovation and commercialization,and Bar-El's(2023)differentiation between knowledge creation and implementation,we analyze the drivers of these two innovation types across national income levels.Using regression analysis on the 2024 Global Innovation Index(GII)and K-means clustering,we identify key patterns among high-and lower-income countries.Our findings reveal a malfunctioning ecosystem for knowledge creation in lower-income countries,where policy support is less effective than it is for the knowledge implementation.Knowledge creation is largely associated with activity by global corporations,contributing to a dual economy with limited local impact.Furthermore,in both income groups,knowledge implementation does not necessarily rely on domestic knowledge creation;instead,these innovation types function independently.In lower-income countries,knowledge implementation is driven by the adaptation of imported knowledge,skilled labor and efficient logistics.We classify lower-income countries into three clusters:(1)high implementation with some creation,(2)corporate-led creation with low implementation,and(3)minimal activity in both domains.These findings suggest that innovation policies in lower-income countries should prioritize implementation-enhancing technology adoption,logistics,and workforce skills.展开更多
A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-t...A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-to-destination signaling.While in the conventional decode and forward(DF)relaying scheme,the source signal is merely duplicated in the relay and the time intervals are equally allocated to the source and relay nodes,this paper considers DRF relaying scheme where versatile time-sharing is adopted for the source and relay nodes which can be optimized based on the relative coordinates of the involved nodes.Two protocols namely unidirectional connection(UC)and bidirectional connection(BC)are proposed based on the source awareness from the relay’s successful reception.The outage probability(OP)performance for both protocols and both DF and DRF relaying schemes is analyzed and tight approximations are obtained.The numerical results show the out-performance of the DRF over the DF relaying scheme in the both UC and BC protocols.Equipped with the obtained system OP,the system throughput is defined and the optimum system throughput is obtained by optimizing the system rate and the timesharing between the source and the relay.Analytical results are corroborated in the numerical examples.展开更多
Surface polaritons,as surface electromagnetic waves propagating along the surface of a medium,have played a crucial role in enhancing photonic spin Hall effect(PSHE)and developing highly sensitive refractive index(RI)...Surface polaritons,as surface electromagnetic waves propagating along the surface of a medium,have played a crucial role in enhancing photonic spin Hall effect(PSHE)and developing highly sensitive refractive index(RI)sensors.Among them,the traditional surface plasmon polariton(SPP)based on noble metals limits its application beyond the near-infrared(IR)regime due to the large negative permittivity and optical losses.In this contribution,we theoretically proposed a highly sensitive PSHE sensor with the structure of Ge prism-SiC-Si:InAs-sensing medium,by taking advantage of the hybrid surface plasmon phonon polariton(SPPhP)in mid-IR regime.Here,heavily Si-doped InAs(Si:InAs)and SiC excite the SPP and surface phonon polariton(SPhP),and the hybrid SPPhP is realized in this system.More importantly,the designed PSHE sensor based on this SPPhP mechanism achieves the multi-stage RI measurements from 1.00025-1.00225 to 1.70025-1.70225,and the maximal intensity sensitivity and angle sensitivity can be up to 9.4×10^(4)μm/RIU and245°/RIU,respectively.These findings provide a new pathway for the enhancement of PSHE in mid-IR regime,and offer new opportunities to develop highly sensitive RI sensors in multi-scenario applications,such as harmful gas monitoring and biosensing.展开更多
Reconfigurable intelligent surface(RIS)have been cast as a promising alternative to alleviate blockage vulnerability and enhance coverage capability for terahertz(THz)communications.Owing to large-scale array elements...Reconfigurable intelligent surface(RIS)have been cast as a promising alternative to alleviate blockage vulnerability and enhance coverage capability for terahertz(THz)communications.Owing to large-scale array elements at transceivers and RIS,the codebook based beamforming can be utilized in a computationally efficient manner.However,the codeword selection for analog beamforming is an intractable combinatorial optimization(CO)problem.To this end,by taking the CO problem as a classification problem,a multi-task learning based analog beam selection(MTL-ABS)framework is developed to implement cooperative beam selection concurrently at transceivers and RIS.In addition,residual network and self-attention mechanism are used to combat the network degradation and mine intrinsic THz channel features.Finally,the network convergence is analyzed from a blockwise perspective,and numerical results demonstrate that the MTL-ABS framework greatly decreases the beam selection overhead and achieves near optimal sum-rate compared with heuristic search based counterparts.展开更多
Vehicular communication systems rely on secure vehicle-to-vehicle(V2V)communications for safety-critical information exchange.However,the presence of eavesdropping vehicles poses a significant challenge.This paper inv...Vehicular communication systems rely on secure vehicle-to-vehicle(V2V)communications for safety-critical information exchange.However,the presence of eavesdropping vehicles poses a significant challenge.This paper investigates the security of V2V communications in reconfigurable intelligent surface(RIS)-assisted vehicular communication systems with spectrum sharing.It proposes a three-stage alternating optimization(TSAO)algorithm to address the complex problem of multiple eavesdropped V2V links that reuse the spectrum already occupied by vehicle-toinfrastructure(V2I)links.To solve the mixed-integer and non-convex optimization problem due to coupled variables and complex constraints,the algorithm decomposes the original problem into three easily solvable sub-problems:RIS reflection coefficient optimization,vehicle transmission power optimization,and spectrum sharing optimization.First,the RIS reflection coefficients are optimized by using the penalty convex-concave procedure(CCP)method.Second,the optimal power points are determined in the power optimization sub-problem.Finally,the spectrum sharing optimization sub-problem is constructed as a weighted bipartite graph matching problem and solved by using the optimal matching algorithm.The TSAO algorithm not only maximizes the sum V2V secrecy rate but also ensures the quality-of-service(QoS)requirements of the V2I links.Simulation results validate the superiority of the proposed algorithm and highlight the improvement in the sum V2V secrecy rate achieved by utilizing RIS technology in vehicular communication systems with spectrum sharing.展开更多
Mammalian sterile-20-like kinase 1(MST1)is a core component of the Hippo signaling pathway.A previous study of 24 patients with MST1 deficiency revealed that more than half of the patients presented symptoms of airway...Mammalian sterile-20-like kinase 1(MST1)is a core component of the Hippo signaling pathway.A previous study of 24 patients with MST1 deficiency revealed that more than half of the patients presented symptoms of airway hyperresponsiveness and atopic dermatitis.We also found significantly reduced MST1 expression in patients with allergies and in mouse models of allergic asthma,suggesting that aberrant MST1 expression may be broadly relevant to allergic diseases.However,the specific mechanism by which MST1 may be related to allergic disorders has remained unclear.In our study,Mst1^(-/-)mice displayed exacerbated IgE-mediated allergic responses,including passive systemic and cutaneous anaphylaxis.More intriguingly,mast cell-deficient Kit^(W-sh/W-sh) mice reconstituted with Mst1^(-/-)bone marrow-derived mast cells(BMMCs)also presented aggravated IgE-mediated hypersensitivity reactions and mast cell-dependent asthma.MST1 deficiency notably promoted inflammatory cytokine production,cell degranulation,and intracellular calcium mobilization in FcεRI-stimulated BMMCs.Mechanistically,MST1 facilitates SRC homology domain-containing tyrosine phosphatase-1(SHP-1)-mediated dephosphorylation of LCK/YES-related protein tyrosine kinase(LYN)at Y397 to repress FcɛRI signaling.Coimmunoprecipitation studies revealed that MST1 acts as a scaffold molecule to enhance the interaction between SHP-1 and LYN in a kinase activity-independent manner.Two patient-derived mutants presented significantly reduced intracellular protein expression levels and impaired LYN-SHP-1 interactions.Our study reveals a noncanonical role of MST1 in maintaining immune homeostasis by preventing mast cell-mediated hypersensitivity.This likely explains the increased susceptibility to allergic diseases in MST1-deficient patients.展开更多
The wireless cloud robotic system(WCRS),which fully integrates sensing,communication,computing,and control capabilities as an intelligent agent,is a promising way to achieve intelligent manufacturing due to easy deplo...The wireless cloud robotic system(WCRS),which fully integrates sensing,communication,computing,and control capabilities as an intelligent agent,is a promising way to achieve intelligent manufacturing due to easy deployment and flexible expansion.However,the high-precision control of WCRS requires deterministic wireless communication,which is always challenging in the complex and dynamic radio space.This paper employs the reconfigurable intelligent surface(RIS)to establish a novel RIS-assisted WCRS architecture,where the radio channel is controlled to achieve ultra-reliable,low-delay,and low-jitter communication for high-precision closed-loop motion control.However,control and communication are strongly coupled and should be co-optimized.Fully considering the constraints of control input threshold,control delay deadline,beam phase,antenna power,and information distortion,we establish a stability maximization problem to jointly optimize control input compensation,RIS phase shift,and beamforming.Herein,a new jitter-oriented system stability objective with respect to control error and communication jitter is defined and the closed-form expression of control delay deadline is derived based on the Jensen Inequality and Lyapunov-Krasovskii functional.Due to the time-varying and partial observability of the channel and robot states,we model the problem as a partially observable Markov decision process(POMDP).To solve this complex problem,we propose a multi-agent transfer reinforcement learning algorithm named LSTM-PPO-MATRL,where the LSTM-enhanced proximal policy optimization(PPO)is designed to approximate an optimal solution and the option-guided policy transfer learning is proposed to facilitate the learning process.By centralized training and decentralized execution,LSTM-PPO-MATRL is validated by extensive experiments on MuJoCo tasks for both low-mobility and high-mobility robotic control scenarios.The results demonstrate that LSTM-PPO-MATRL not only realizes high learning efficiency,but also supports low-delay,low-jitter communication for low error control,where 71.9%control accuracy improvement and 68.7%delay jitter reduction are achieved compared to the PPO-MADRL baseline.展开更多
文摘Imminent abortion needs more serious attention since it remains a big problem in Indonesia considering its epidemiology, morbidity, mortality,?and prognosis. In fact, some cases can still be prevented.?The objective of this study was to determine pathogenesis, diagnosis,?and prognosis of imminent abortion through the role of antioxidant vitamin C in the interaction of superoxide dismutase (SOD), interferon-γ?(IFN-γ), interleukin-4 (IL-4), vascular cells adhesion molecule-1?(VCAM-1), and decidual spiral artery resistance index (DSA RI).?This study took 10 months from March to December 2007 at Obstetrics and Gynecology Department of Medical Faculty of?Padjadjaran?University/Hasan Sadikin Hospital, Bandung. Sixty pregnant women who met the inclusion and exclusion criteria were divided into two groups with the random clinical trial method, double-blind with?repeated measurements.?Data were analyzed statistically using t test, Mann-Whitney, Rank?Spearman, Wilcoxon, t paired, and diagnostic test.?The results of this study showed that the incidence of abortion in vitamin C group was 9 cases (30%) and placebo group was 13 cases (43.3%). There was a significant difference in SOD, IFN-γ, IL-4 and VCAM-1 level between groups of women with and without abortion (p < 0.001).?There was a significant difference of SOD level between women with abortion 655.8 (163.6) U/gHb and placebo group 824.5 (106.7) U/gHb after vitamin C administration (p = 0.008). The cutoff point of SOD?was?￡992 U/gHbwhich?showed quite high sensitivity, specificity, accuracy,?and significant difference (p < 0.001). The cutoff point abortion of DSA resistance index was ≥0.55 with 45% accuracy (p = 0.002). The highest change of IL-4 level was 60.7% in vitamin C group and VCAM-1 was?-2.2% (p < 0.05) after?vitamin C administration. There was a negative correlation in SOD changes toward IL-4 changes after vitamin C administration (r =?-0.523) (p = 0.003), a positive correlation between SOD changes and IL-4 changes (0.597) (p < 0.001), a negative correlation between SOD changes and VCAM-1 changes (r =?-0.737) (p < 0.001) and a negative correlation between SOD changes and DSA RI changes (r =?-0.208) (p = 0.022). There were significant changes in the increment of IL-4 and SOD level (p < 0.001) and a decline in IFN-γ, VCAM-1 and DSA RI (p < 0.001) before and after vitamin C administration. In conclusion, there?was a correlation between the?increase of SOD level with?the?decrease of INF-γ?level and?the?increase of IL-4 level in imminent abortion after vitamin C administration. There?was a correlation between?the?increase of SOD level with?the?decrease of DSA RI and?the?decrease of VCAM-1 level in imminent abortion after vitamin C administration. In abortion, there?was?a?decrease of SOD and IL-4 level,?as well as an?increase of IFN-γ, VCAM-1, and DSA RI level.
文摘Lower-income countries face a persistent challenge:innovation activities tend to concentrate in more developed regions.Existing research offers limited solutions,often emphasizing local advantages or frugal innovation to reduce regional disparities.This study challenges the conventional approach of competing with advanced economies and proposes an"integrative"strategy that treats innovation as a multifaceted process encompassing diverse activities.Building on Capello and Lenzi's(2014)distinction between innovation and commercialization,and Bar-El's(2023)differentiation between knowledge creation and implementation,we analyze the drivers of these two innovation types across national income levels.Using regression analysis on the 2024 Global Innovation Index(GII)and K-means clustering,we identify key patterns among high-and lower-income countries.Our findings reveal a malfunctioning ecosystem for knowledge creation in lower-income countries,where policy support is less effective than it is for the knowledge implementation.Knowledge creation is largely associated with activity by global corporations,contributing to a dual economy with limited local impact.Furthermore,in both income groups,knowledge implementation does not necessarily rely on domestic knowledge creation;instead,these innovation types function independently.In lower-income countries,knowledge implementation is driven by the adaptation of imported knowledge,skilled labor and efficient logistics.We classify lower-income countries into three clusters:(1)high implementation with some creation,(2)corporate-led creation with low implementation,and(3)minimal activity in both domains.These findings suggest that innovation policies in lower-income countries should prioritize implementation-enhancing technology adoption,logistics,and workforce skills.
文摘A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-to-destination signaling.While in the conventional decode and forward(DF)relaying scheme,the source signal is merely duplicated in the relay and the time intervals are equally allocated to the source and relay nodes,this paper considers DRF relaying scheme where versatile time-sharing is adopted for the source and relay nodes which can be optimized based on the relative coordinates of the involved nodes.Two protocols namely unidirectional connection(UC)and bidirectional connection(BC)are proposed based on the source awareness from the relay’s successful reception.The outage probability(OP)performance for both protocols and both DF and DRF relaying schemes is analyzed and tight approximations are obtained.The numerical results show the out-performance of the DRF over the DF relaying scheme in the both UC and BC protocols.Equipped with the obtained system OP,the system throughput is defined and the optimum system throughput is obtained by optimizing the system rate and the timesharing between the source and the relay.Analytical results are corroborated in the numerical examples.
基金Project supported by the National Natural Science Foundation of China(Grant No.12175107)the Qing Lan Project of Jiangsu Province+2 种基金the Hua Li Talents Program of Nanjing University of PostsTelecommunications,Natural Science Foundation of Nanjing Vocational University of Industry Technology(Grant No.YK22-02-08)the Fund from the Research Center of Industrial Perception and Intelligent Manufacturing Equipment Engineering of Jiangsu Province,China(Grant No.ZK21-05-09)。
文摘Surface polaritons,as surface electromagnetic waves propagating along the surface of a medium,have played a crucial role in enhancing photonic spin Hall effect(PSHE)and developing highly sensitive refractive index(RI)sensors.Among them,the traditional surface plasmon polariton(SPP)based on noble metals limits its application beyond the near-infrared(IR)regime due to the large negative permittivity and optical losses.In this contribution,we theoretically proposed a highly sensitive PSHE sensor with the structure of Ge prism-SiC-Si:InAs-sensing medium,by taking advantage of the hybrid surface plasmon phonon polariton(SPPhP)in mid-IR regime.Here,heavily Si-doped InAs(Si:InAs)and SiC excite the SPP and surface phonon polariton(SPhP),and the hybrid SPPhP is realized in this system.More importantly,the designed PSHE sensor based on this SPPhP mechanism achieves the multi-stage RI measurements from 1.00025-1.00225 to 1.70025-1.70225,and the maximal intensity sensitivity and angle sensitivity can be up to 9.4×10^(4)μm/RIU and245°/RIU,respectively.These findings provide a new pathway for the enhancement of PSHE in mid-IR regime,and offer new opportunities to develop highly sensitive RI sensors in multi-scenario applications,such as harmful gas monitoring and biosensing.
文摘Reconfigurable intelligent surface(RIS)have been cast as a promising alternative to alleviate blockage vulnerability and enhance coverage capability for terahertz(THz)communications.Owing to large-scale array elements at transceivers and RIS,the codebook based beamforming can be utilized in a computationally efficient manner.However,the codeword selection for analog beamforming is an intractable combinatorial optimization(CO)problem.To this end,by taking the CO problem as a classification problem,a multi-task learning based analog beam selection(MTL-ABS)framework is developed to implement cooperative beam selection concurrently at transceivers and RIS.In addition,residual network and self-attention mechanism are used to combat the network degradation and mine intrinsic THz channel features.Finally,the network convergence is analyzed from a blockwise perspective,and numerical results demonstrate that the MTL-ABS framework greatly decreases the beam selection overhead and achieves near optimal sum-rate compared with heuristic search based counterparts.
基金National Natural Science Foundation of China(Nos.61772130,71171045 and 61901104)Innovation Program of Shanghai Municipal Education Commission,China(No.14YZ130)。
文摘Vehicular communication systems rely on secure vehicle-to-vehicle(V2V)communications for safety-critical information exchange.However,the presence of eavesdropping vehicles poses a significant challenge.This paper investigates the security of V2V communications in reconfigurable intelligent surface(RIS)-assisted vehicular communication systems with spectrum sharing.It proposes a three-stage alternating optimization(TSAO)algorithm to address the complex problem of multiple eavesdropped V2V links that reuse the spectrum already occupied by vehicle-toinfrastructure(V2I)links.To solve the mixed-integer and non-convex optimization problem due to coupled variables and complex constraints,the algorithm decomposes the original problem into three easily solvable sub-problems:RIS reflection coefficient optimization,vehicle transmission power optimization,and spectrum sharing optimization.First,the RIS reflection coefficients are optimized by using the penalty convex-concave procedure(CCP)method.Second,the optimal power points are determined in the power optimization sub-problem.Finally,the spectrum sharing optimization sub-problem is constructed as a weighted bipartite graph matching problem and solved by using the optimal matching algorithm.The TSAO algorithm not only maximizes the sum V2V secrecy rate but also ensures the quality-of-service(QoS)requirements of the V2I links.Simulation results validate the superiority of the proposed algorithm and highlight the improvement in the sum V2V secrecy rate achieved by utilizing RIS technology in vehicular communication systems with spectrum sharing.
基金supported by grants from the National Natural Science Foundation of China(8187060308,U22A20307,and 81930041)the Key R&D Program of Zhejiang Province(2024C03177)+1 种基金the Noncommunicable Chronic Diseases-National Science and Technology Major Project(2024ZD0541200)the Natural Science Foundation of Zhejiang Province(LZ24H100001).
文摘Mammalian sterile-20-like kinase 1(MST1)is a core component of the Hippo signaling pathway.A previous study of 24 patients with MST1 deficiency revealed that more than half of the patients presented symptoms of airway hyperresponsiveness and atopic dermatitis.We also found significantly reduced MST1 expression in patients with allergies and in mouse models of allergic asthma,suggesting that aberrant MST1 expression may be broadly relevant to allergic diseases.However,the specific mechanism by which MST1 may be related to allergic disorders has remained unclear.In our study,Mst1^(-/-)mice displayed exacerbated IgE-mediated allergic responses,including passive systemic and cutaneous anaphylaxis.More intriguingly,mast cell-deficient Kit^(W-sh/W-sh) mice reconstituted with Mst1^(-/-)bone marrow-derived mast cells(BMMCs)also presented aggravated IgE-mediated hypersensitivity reactions and mast cell-dependent asthma.MST1 deficiency notably promoted inflammatory cytokine production,cell degranulation,and intracellular calcium mobilization in FcεRI-stimulated BMMCs.Mechanistically,MST1 facilitates SRC homology domain-containing tyrosine phosphatase-1(SHP-1)-mediated dephosphorylation of LCK/YES-related protein tyrosine kinase(LYN)at Y397 to repress FcɛRI signaling.Coimmunoprecipitation studies revealed that MST1 acts as a scaffold molecule to enhance the interaction between SHP-1 and LYN in a kinase activity-independent manner.Two patient-derived mutants presented significantly reduced intracellular protein expression levels and impaired LYN-SHP-1 interactions.Our study reveals a noncanonical role of MST1 in maintaining immune homeostasis by preventing mast cell-mediated hypersensitivity.This likely explains the increased susceptibility to allergic diseases in MST1-deficient patients.
基金supported in part by the National Natural Science Foundation of China(62522320,92267108,62173322)Liaoning Revitalization Talents Program(XLYC2403062)the Science and Technology Program of Liaoning Province(2023JH3/10200004,2022JH25/10100005)。
文摘The wireless cloud robotic system(WCRS),which fully integrates sensing,communication,computing,and control capabilities as an intelligent agent,is a promising way to achieve intelligent manufacturing due to easy deployment and flexible expansion.However,the high-precision control of WCRS requires deterministic wireless communication,which is always challenging in the complex and dynamic radio space.This paper employs the reconfigurable intelligent surface(RIS)to establish a novel RIS-assisted WCRS architecture,where the radio channel is controlled to achieve ultra-reliable,low-delay,and low-jitter communication for high-precision closed-loop motion control.However,control and communication are strongly coupled and should be co-optimized.Fully considering the constraints of control input threshold,control delay deadline,beam phase,antenna power,and information distortion,we establish a stability maximization problem to jointly optimize control input compensation,RIS phase shift,and beamforming.Herein,a new jitter-oriented system stability objective with respect to control error and communication jitter is defined and the closed-form expression of control delay deadline is derived based on the Jensen Inequality and Lyapunov-Krasovskii functional.Due to the time-varying and partial observability of the channel and robot states,we model the problem as a partially observable Markov decision process(POMDP).To solve this complex problem,we propose a multi-agent transfer reinforcement learning algorithm named LSTM-PPO-MATRL,where the LSTM-enhanced proximal policy optimization(PPO)is designed to approximate an optimal solution and the option-guided policy transfer learning is proposed to facilitate the learning process.By centralized training and decentralized execution,LSTM-PPO-MATRL is validated by extensive experiments on MuJoCo tasks for both low-mobility and high-mobility robotic control scenarios.The results demonstrate that LSTM-PPO-MATRL not only realizes high learning efficiency,but also supports low-delay,low-jitter communication for low error control,where 71.9%control accuracy improvement and 68.7%delay jitter reduction are achieved compared to the PPO-MADRL baseline.
