With increasing density and heterogeneity in unlicensed wireless networks,traditional MAC protocols,such as Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA)in Wi-Fi networks,are experiencing performance...With increasing density and heterogeneity in unlicensed wireless networks,traditional MAC protocols,such as Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA)in Wi-Fi networks,are experiencing performance degradation.This is manifested in increased collisions and extended backoff times,leading to diminished spectrum efficiency and protocol coordination.Addressing these issues,this paper proposes a deep-learning-based MAC paradigm,dubbed DL-MAC,which leverages spectrum data readily available from energy detection modules in wireless devices to achieve the MAC functionalities of channel access,rate adaptation,and channel switch.First,we utilize DL-MAC to realize a joint design of channel access and rate adaptation.Subsequently,we integrate the capability of channel switching into DL-MAC,enhancing its functionality from single-channel to multi-channel operations.Specifically,the DL-MAC protocol incorporates a Deep Neural Network(DNN)for channel selection and a Recurrent Neural Network(RNN)for the joint design of channel access and rate adaptation.We conducted real-world data collection within the 2.4 GHz frequency band to validate the effectiveness of DL-MAC.Experimental results demonstrate that DL-MAC exhibits significantly superior performance compared to traditional algorithms in both single and multi-channel environments,and also outperforms single-function designs.Additionally,the performance of DL-MAC remains robust,unaffected by channel switch overheads within the evaluation range.展开更多
Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of pr...Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of protocols,in this paper,we propose a novel routing protocol: optimized cross-layer AODV( CL_ AODV) designed for VANET. It utilizes the frame transmission efficiency( FTE),path bandwidth in media access control( MAC) layer and signal-to-noise ratio( SNIR) in physical( PHY) layer to improve the link stability. In other words,it can increase packet delivery ratio effectively. In addition,end-to-end delay will be decreased based on the channel switching. According to the simulation,it is shown that the packet delivery ratio of CL_AODV is almost up to 99% and the highest compared to AODV and muti-constrained QoS AODV( MQ_ AODV). The delay of CL_AODV is almost half of MQ_ AODV's and 1 /3 of AODV's.Meanwhile,CL_AODV has the highest routing overhead or energy consuming. Because of the feature of VANET,the disadvantage can be ignored.展开更多
Visible-infrared object detection leverages the day-night stable object perception capability of infrared images to enhance detection robustness in low-light environments by fusing the complementary information of vis...Visible-infrared object detection leverages the day-night stable object perception capability of infrared images to enhance detection robustness in low-light environments by fusing the complementary information of visible and infrared images.However,the inherent differences in the imaging mechanisms of visible and infrared modalities make effective cross-modal fusion challenging.Furthermore,constrained by the physical characteristics of sensors and thermal diffusion effects,infrared images generally suffer from blurred object contours and missing details,making it difficult to extract object features effectively.To address these issues,we propose an infrared-visible image fusion network that realizesmultimodal information fusion of infrared and visible images through a carefully designedmultiscale fusion strategy.First,we design an adaptive gray-radiance enhancement(AGRE)module to strengthen the detail representation in infrared images,improving their usability in complex lighting scenarios.Next,we introduce a channelspatial feature interaction(CSFI)module,which achieves efficient complementarity between the RGB and infrared(IR)modalities via dynamic channel switching and a spatial attention mechanism.Finally,we propose a multi-scale enhanced cross-attention fusion(MSECA)module,which optimizes the fusion ofmulti-level features through dynamic convolution and gating mechanisms and captures long-range complementary relationships of cross-modal features on a global scale,thereby enhancing the expressiveness of the fused features.Experiments on the KAIST,M3FD,and FLIR datasets demonstrate that our method delivers outstanding performance in daytime and nighttime scenarios.On the KAIST dataset,the miss rate drops to 5.99%,and further to 4.26% in night scenes.On the FLIR and M3FD datasets,it achieves AP50 scores of 79.4% and 88.9%,respectively.展开更多
A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high vol...A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high voltage electrodes with a uniform gap length of 5 ram. The self breakdown and triggered breakdown performance of the switch are reported. Both the delay time and jitter decrease with the increase in the trigger voltage, switching coefficient and the decrease in the trigger isolating resistor. The delay time of the switch is about 40 ns, and the jitter is less than 2 ns when charged with 4-85 kV and triggered by a voltage pule of -75 kV. The inductance of the switch is about 30 nH.展开更多
Understanding of the mechanisms of neural phase transitions is crucial for clarifying cognitive processes in the brain. We investigate a neural oscillator that undergoes different bifurcation transitions from the big ...Understanding of the mechanisms of neural phase transitions is crucial for clarifying cognitive processes in the brain. We investigate a neural oscillator that undergoes different bifurcation transitions from the big saddle homoclinic orbit type to the saddle node on an invariant circle type, and the saddle node on an invariant circle type to the small saddle homoclinic orbit type. The bifurcation transitions are accompanied by an increase in thermodynamic temperature that affects the voltage-gated ion channel in the neural oscillator. We show that nonlinear and thermodynamical mechanisms are responsible for different switches of the frequency in the neural oscillator. We report a dynamical role of the phase response curve in switches of the frequency, in terms of slopes of frequency-temperature curve at each bifurcation transition. Adopting the transition state theory of voltagegated ion channel dynamics, we confirm that switches of the frequency occur in the first-order phase transition temperature states and exhibit different features of their potential energy derivatives in the ion channel. Each bifurcation transition also creates a discontinuity in the Arrhenius plot used to compute the time constant of the ion channel.展开更多
In Ambient Assistant Living(AAL) systems, it is a fundamental problem to ensure prompt delivery of detected events, such as irregular heart rate or fall of elderly, to a central processing device(e.g. gateway node). M...In Ambient Assistant Living(AAL) systems, it is a fundamental problem to ensure prompt delivery of detected events, such as irregular heart rate or fall of elderly, to a central processing device(e.g. gateway node). Most of recently proposed MAC protocols for low-power embedded sensing systems(e.g. wireless sensor networks) are designed with energy efficiency as the first goal, so they are not suitable for AAL systems. Although some multi-channel MAC protocols have been proposed to address the problem, most of those protocols ignore the cost of channel switching, which can have reverse effect on network performance, especially latency of data delivery. In this paper, we propose a Delay-Sensitive Multi-channel MAC protocol(DS-MMAC) for AAL systems, which can provide high packet delivery ratio and bound low latency for data delivered to the gateway node. The novelty of the protocol is that an efficient distributed time slot scheduling and channel assignment algorithm is combined with the process of route establishment, which takes the channel switching cost into account and reduces endto-end delay to meet the required delay bound of each data flow. The performance of the proposed protocol is evaluated through extensive simulations. Results show that DS-MMAC can bound low latency for delivering detected events in AAL system to the gateway, while providing high delivery reliability and low energy consumption.展开更多
In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimat...In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimation error was studied and we verified by simulations that the spatial multiplexing outperforms the switching algorithm. Given that the switching algorithm is based on the comparison of the channel matrix Demmel condition number to a threshold, its accuracy is compromised when channel estimation error in-creases. As a first intuitive solution, we proceeded to the adaptation of the threshold, but this didn’t lead to a pertinent improvement for the main reason that channel estimation errors did affect the MIMO techniques which use different constellation. Based on that, we proposed a new estimation technique that improved the bit error rate performance significantly.展开更多
An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were o...An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were obtained. The phase shift distributions of the plasma were extracted by numerically processing the interferograms. The three-dimensional(3 D) electron density distributions of the air-spark switch plasma were then obtained. The working process of the air-spark switch was described by analyzing the temporal and spatial evolution of the plasma electron density.展开更多
In this paper, a time-switched space-time （TSST） coded orthogonal frequency division nmltiplexing （OFDM） scheme against the time-varying channels is proposed. In the TSST-OFDM scheme, it is equipped with four tran...In this paper, a time-switched space-time （TSST） coded orthogonal frequency division nmltiplexing （OFDM） scheme against the time-varying channels is proposed. In the TSST-OFDM scheme, it is equipped with four transmit antennas, but only double of them are used for coding in every time slot. It is shown that the signal to inter-antenna interference ratio is a function of Doppler frequency in time-varying channels for a given space-time code. The analyses and simulations results validate that the proposed scheme not only gets time- switched diversity and lower decoding complexity, but also suffers less time-varying impairments. Hence, it ex- hibits better performance than quasi-orthogonal space-time coded scheme.展开更多
为解决SONiC(software for open networking in the cloud)交换机操作系统对多模态网络(polymor phic network,PINet)中模态适配及模态管控问题,提出了一个基于P4Runtime的SONiC网元控制通道容器p4runtime-pins,使多模态网元设备可以支...为解决SONiC(software for open networking in the cloud)交换机操作系统对多模态网络(polymor phic network,PINet)中模态适配及模态管控问题,提出了一个基于P4Runtime的SONiC网元控制通道容器p4runtime-pins,使多模态网元设备可以支持多种网络模态流表的配置。p4runtime-pins容器通过gRPC服务模块实现与控制器的连接,使用邻近网元发现算法实现控制器对链路的发现。设计了网元端口更新算法解决了网元设备在实际应用环境中存在的端口变更问题。同时,针对SONiC网元交换机中硬件转发处理单元存在的流表支持性差异问题,设计了内部流表转存和gRPC网元代理功能,实现了不同网络模态流表的部署。实验结果表明,p4runtime-pins容器资源消耗低,仅占用了1.70%的CPU资源和0.45%的内存资源。同时,部署p4runtime-pins容器的SONiC网元设备能够准确地接收并配置控制器下发的流表规则,流表配置延迟仅为0.027~0.037 s。展开更多
基金supported in part by the National Key R&D Program of China under Grant 2021YFB1714100in part by the Shenzhen Science and Technology Program,China,under Grant JCYJ20220531101015033.
文摘With increasing density and heterogeneity in unlicensed wireless networks,traditional MAC protocols,such as Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA)in Wi-Fi networks,are experiencing performance degradation.This is manifested in increased collisions and extended backoff times,leading to diminished spectrum efficiency and protocol coordination.Addressing these issues,this paper proposes a deep-learning-based MAC paradigm,dubbed DL-MAC,which leverages spectrum data readily available from energy detection modules in wireless devices to achieve the MAC functionalities of channel access,rate adaptation,and channel switch.First,we utilize DL-MAC to realize a joint design of channel access and rate adaptation.Subsequently,we integrate the capability of channel switching into DL-MAC,enhancing its functionality from single-channel to multi-channel operations.Specifically,the DL-MAC protocol incorporates a Deep Neural Network(DNN)for channel selection and a Recurrent Neural Network(RNN)for the joint design of channel access and rate adaptation.We conducted real-world data collection within the 2.4 GHz frequency band to validate the effectiveness of DL-MAC.Experimental results demonstrate that DL-MAC exhibits significantly superior performance compared to traditional algorithms in both single and multi-channel environments,and also outperforms single-function designs.Additionally,the performance of DL-MAC remains robust,unaffected by channel switch overheads within the evaluation range.
基金National Natural Science Foundation of China(No.71171045)
文摘Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of protocols,in this paper,we propose a novel routing protocol: optimized cross-layer AODV( CL_ AODV) designed for VANET. It utilizes the frame transmission efficiency( FTE),path bandwidth in media access control( MAC) layer and signal-to-noise ratio( SNIR) in physical( PHY) layer to improve the link stability. In other words,it can increase packet delivery ratio effectively. In addition,end-to-end delay will be decreased based on the channel switching. According to the simulation,it is shown that the packet delivery ratio of CL_AODV is almost up to 99% and the highest compared to AODV and muti-constrained QoS AODV( MQ_ AODV). The delay of CL_AODV is almost half of MQ_ AODV's and 1 /3 of AODV's.Meanwhile,CL_AODV has the highest routing overhead or energy consuming. Because of the feature of VANET,the disadvantage can be ignored.
基金supported by the National Natural Science Foundation of China(Grant No.62302086)the Natural Science Foundation of Liaoning Province(Grant No.2023-MSBA-070)the Fundamental Research Funds for the Central Universities(Grant No.N2317005).
文摘Visible-infrared object detection leverages the day-night stable object perception capability of infrared images to enhance detection robustness in low-light environments by fusing the complementary information of visible and infrared images.However,the inherent differences in the imaging mechanisms of visible and infrared modalities make effective cross-modal fusion challenging.Furthermore,constrained by the physical characteristics of sensors and thermal diffusion effects,infrared images generally suffer from blurred object contours and missing details,making it difficult to extract object features effectively.To address these issues,we propose an infrared-visible image fusion network that realizesmultimodal information fusion of infrared and visible images through a carefully designedmultiscale fusion strategy.First,we design an adaptive gray-radiance enhancement(AGRE)module to strengthen the detail representation in infrared images,improving their usability in complex lighting scenarios.Next,we introduce a channelspatial feature interaction(CSFI)module,which achieves efficient complementarity between the RGB and infrared(IR)modalities via dynamic channel switching and a spatial attention mechanism.Finally,we propose a multi-scale enhanced cross-attention fusion(MSECA)module,which optimizes the fusion ofmulti-level features through dynamic convolution and gating mechanisms and captures long-range complementary relationships of cross-modal features on a global scale,thereby enhancing the expressiveness of the fused features.Experiments on the KAIST,M3FD,and FLIR datasets demonstrate that our method delivers outstanding performance in daytime and nighttime scenarios.On the KAIST dataset,the miss rate drops to 5.99%,and further to 4.26% in night scenes.On the FLIR and M3FD datasets,it achieves AP50 scores of 79.4% and 88.9%,respectively.
基金supported by National Natural Science Foundation of China(Nos.50477019,50637010)the State Key Laboratory of Electrical Insulation and Power Equipment of China(EIPE.09207)
文摘A multi-gap and multi-channel gas switch with convexo-convex discal planet electrodes was designed and investigated. Eight gaps are formed in series by a trigger electrode, six intermediate electrodes and two high voltage electrodes with a uniform gap length of 5 ram. The self breakdown and triggered breakdown performance of the switch are reported. Both the delay time and jitter decrease with the increase in the trigger voltage, switching coefficient and the decrease in the trigger isolating resistor. The delay time of the switch is about 40 ns, and the jitter is less than 2 ns when charged with 4-85 kV and triggered by a voltage pule of -75 kV. The inductance of the switch is about 30 nH.
基金Supported by JST,CREST,and JSPS KAKENHI under Grant No 15H05919
文摘Understanding of the mechanisms of neural phase transitions is crucial for clarifying cognitive processes in the brain. We investigate a neural oscillator that undergoes different bifurcation transitions from the big saddle homoclinic orbit type to the saddle node on an invariant circle type, and the saddle node on an invariant circle type to the small saddle homoclinic orbit type. The bifurcation transitions are accompanied by an increase in thermodynamic temperature that affects the voltage-gated ion channel in the neural oscillator. We show that nonlinear and thermodynamical mechanisms are responsible for different switches of the frequency in the neural oscillator. We report a dynamical role of the phase response curve in switches of the frequency, in terms of slopes of frequency-temperature curve at each bifurcation transition. Adopting the transition state theory of voltagegated ion channel dynamics, we confirm that switches of the frequency occur in the first-order phase transition temperature states and exhibit different features of their potential energy derivatives in the ion channel. Each bifurcation transition also creates a discontinuity in the Arrhenius plot used to compute the time constant of the ion channel.
基金supported by the International S&T Cooperation Program of China (ISTCP) under Grant No. 2013DFA10690the National Science Foundation of China (NSFC) under Grant No. 61100180
文摘In Ambient Assistant Living(AAL) systems, it is a fundamental problem to ensure prompt delivery of detected events, such as irregular heart rate or fall of elderly, to a central processing device(e.g. gateway node). Most of recently proposed MAC protocols for low-power embedded sensing systems(e.g. wireless sensor networks) are designed with energy efficiency as the first goal, so they are not suitable for AAL systems. Although some multi-channel MAC protocols have been proposed to address the problem, most of those protocols ignore the cost of channel switching, which can have reverse effect on network performance, especially latency of data delivery. In this paper, we propose a Delay-Sensitive Multi-channel MAC protocol(DS-MMAC) for AAL systems, which can provide high packet delivery ratio and bound low latency for data delivered to the gateway node. The novelty of the protocol is that an efficient distributed time slot scheduling and channel assignment algorithm is combined with the process of route establishment, which takes the channel switching cost into account and reduces endto-end delay to meet the required delay bound of each data flow. The performance of the proposed protocol is evaluated through extensive simulations. Results show that DS-MMAC can bound low latency for delivering detected events in AAL system to the gateway, while providing high delivery reliability and low energy consumption.
文摘In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimation error was studied and we verified by simulations that the spatial multiplexing outperforms the switching algorithm. Given that the switching algorithm is based on the comparison of the channel matrix Demmel condition number to a threshold, its accuracy is compromised when channel estimation error in-creases. As a first intuitive solution, we proceeded to the adaptation of the threshold, but this didn’t lead to a pertinent improvement for the main reason that channel estimation errors did affect the MIMO techniques which use different constellation. Based on that, we proposed a new estimation technique that improved the bit error rate performance significantly.
文摘An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were obtained. The phase shift distributions of the plasma were extracted by numerically processing the interferograms. The three-dimensional(3 D) electron density distributions of the air-spark switch plasma were then obtained. The working process of the air-spark switch was described by analyzing the temporal and spatial evolution of the plasma electron density.
基金Sponsored by the Science and Technology Project of Dalian,China (Grant No. 2011J21DW009)
文摘In this paper, a time-switched space-time （TSST） coded orthogonal frequency division nmltiplexing （OFDM） scheme against the time-varying channels is proposed. In the TSST-OFDM scheme, it is equipped with four transmit antennas, but only double of them are used for coding in every time slot. It is shown that the signal to inter-antenna interference ratio is a function of Doppler frequency in time-varying channels for a given space-time code. The analyses and simulations results validate that the proposed scheme not only gets time- switched diversity and lower decoding complexity, but also suffers less time-varying impairments. Hence, it ex- hibits better performance than quasi-orthogonal space-time coded scheme.
文摘为解决SONiC(software for open networking in the cloud)交换机操作系统对多模态网络(polymor phic network,PINet)中模态适配及模态管控问题,提出了一个基于P4Runtime的SONiC网元控制通道容器p4runtime-pins,使多模态网元设备可以支持多种网络模态流表的配置。p4runtime-pins容器通过gRPC服务模块实现与控制器的连接,使用邻近网元发现算法实现控制器对链路的发现。设计了网元端口更新算法解决了网元设备在实际应用环境中存在的端口变更问题。同时,针对SONiC网元交换机中硬件转发处理单元存在的流表支持性差异问题,设计了内部流表转存和gRPC网元代理功能,实现了不同网络模态流表的部署。实验结果表明,p4runtime-pins容器资源消耗低,仅占用了1.70%的CPU资源和0.45%的内存资源。同时,部署p4runtime-pins容器的SONiC网元设备能够准确地接收并配置控制器下发的流表规则,流表配置延迟仅为0.027~0.037 s。
