The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can ...The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process,because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. Whendivergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence.Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selectionagainst intermediate phenotypes that are maladapted to their (sensory) environment. For Lake Victoria cichlids, the visual environmentconstitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigatethe direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours(red and blue) in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extractgeneral principles, and discuss future perspectives [Current Zoology 56 (3): 285-299, 2010].展开更多
The rapid advancements in humanoid robotics and autonomous driving demand smart artificial optoelectronic vision systems that can emulate humanlike perception.Although many studies have reported multi-functional visua...The rapid advancements in humanoid robotics and autonomous driving demand smart artificial optoelectronic vision systems that can emulate humanlike perception.Although many studies have reported multi-functional visual chips based on artificial optoelectronic synaptic devices,few can simulate complex behavioral characteristics of humans,like specific living habits and physiological adaptations.In this study,we demonstrated MoS_(2)optoelectronic synapses capable of exhibiting tunable human-like visual adaptation abilities under various alcohol concentrations,featuring remarkable photo-induced conductance plasticity for emulating alcohol-sensitive human visual recognition.Two working mechanisms involving hydrogen-atom and oxygen-atom doping were unveiled during the concentration-dependent doping process.The visual adaptation abilities were systematically explored by controlling the doping concentration of alcohol molecules,and were further enhanced by electric and optoelectronic stimuli to emulate human-like behaviors,such as slight drunkenness,heavy drunkenness,and sobering up.Under the influence of alcohol molecules and the modulation of device operating voltage,the accuracy of handwritten digit recognition for this device has greatly increased from 78.9%to 94.7%.展开更多
The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown....The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown. Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes, and thus may carry accurate stimulus-related information. Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus. The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency （bursts/s） and burst length （spikes/burst）, but increased burst duration and the interspike interval within bursts. These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections, which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.展开更多
The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation,but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown.C...The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation,but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown.Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes,and thus may carry accurate stimulus-related information.Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus.The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency(bursts/s)and burst length(spikes/burst),but increased burst duration and the interspike interval within bursts.These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections,which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.展开更多
Visual background extraction algorithm(ViBe)uses the first frame image to initialize the background model,which can easily introduce the“ghost”.Because ViBe uses the fixed segmentation threshold to achieve the foreg...Visual background extraction algorithm(ViBe)uses the first frame image to initialize the background model,which can easily introduce the“ghost”.Because ViBe uses the fixed segmentation threshold to achieve the foreground and background segmentation,the detection results in many false detections for the highly dynamic background.To solve these problems,an improved ghost suppression and adaptive Visual Background Extraction algorithm is proposed in this paper.Firstly,with the pixel’s temporal and spatial information,the historical pixels of a certain combination are used to initialize the background model in the odd frames of the video sequence.Secondly,the background sample set combined with the neighborhood pixels are used to determine a complex degree of the background,to acquire the adaptive segmentation threshold.Thirdly,the update rate is adjusted based on the complexity of the background.Finally,the detected result goes through a post-processing to achieve better detection results.The experimental results show that the improved algorithm will not only quickly suppress the“ghost”,but also have a better detection in a complex dynamic background.展开更多
Bioinspired neuromorphic machine vision system(NMVS)that integrates retinomorphic sensing and neuromorphic computing into one monolithic system is regarded as the most promising architecture for visual perception.Howe...Bioinspired neuromorphic machine vision system(NMVS)that integrates retinomorphic sensing and neuromorphic computing into one monolithic system is regarded as the most promising architecture for visual perception.However,the large intensity range of natural lights and complex illumination conditions in actual scenarios always require the NMVS to dynamically adjust its sensitivity according to the environmental conditions,just like the visual adaptation function of the human retina.Although some opto-sensors with scotopic or photopic adaption have been developed,NMVSs,especially fully flexible NMVSs,with both scotopic and photopic adaptation functions are rarely reported.Here we propose an ion-modulation strategy to dynamically adjust the photosensitivity and time-varying activation/inhibition characteristics depending on the illumination conditions,and develop a flexible ionmodulated phototransistor array based on MoS_(2)/graphdiyne heterostructure,which can execute both retinomorphic sensing and neuromorphic computing.By controlling the intercalated Li^(+) ions in graphdiyne,both scotopic and photopic adaptation functions are demonstrated successfully.A fully flexible NMVS consisting of front-end retinomorphic vision sensors and a back-end convolutional neural network is constructed based on the as-fabricated 28×28 device array,demonstrating quite high recognition accuracies for both dim and bright images and robust flexibility.This effort for fully flexible and monolithic NMVS paves the way for its applications in wearable scenarios.展开更多
Adaptive rendering large and complex spatial data has become an important research issue in a 3DGIS application. In order to transmit the data to the client efficiently, this paper proposes a node-layer data model to ...Adaptive rendering large and complex spatial data has become an important research issue in a 3DGIS application. In order to transmit the data to the client efficiently, this paper proposes a node-layer data model to manage the 3D scene. Because the large spatial data and limited network bandwidth are the main bottlenecks of web-based 3DGIS, a client/server architecture including progressive transmission methods and multiresolution representations, together with the spatial index, are developed to improve the performance. All this makes the application quite scalable. Experimental results reveal that the application works appropriately.展开更多
3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent up...3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent upon the performance of computer hardware.Thus,achieving the efficient rendering of 3D city models using different hardware performance levels represents one of the key problems currently facing researchers.This paper proposes a time-critical adaptive visualization method that first estimates the possible rendering time for each model according to the data structure of the model in addition to the CPU/GPU performance of the computer.It then dynamically adjusts the rendering level for each model based on the results of an estimation of the rendering time to ensure that the final scene can be completed within a given time.To verify the effectiveness and flexibility of this method,it is applied using different computers.The results show that the adaptive visualization method presented in this paper not only can adapt to computers with different levels of performances but also demonstrates an obvious improvement in the time estimation precision,visual effects,and optimization speed relative to existing adaptive visualization methods.展开更多
An objective visual performance evaluation with visual evoked potential （VEP） measurements was first inte- grated into an adaptive optics （AO） system. The optical and neural limits to vision can be bypassed throug...An objective visual performance evaluation with visual evoked potential （VEP） measurements was first inte- grated into an adaptive optics （AO） system. The optical and neural limits to vision can be bypassed through this system. Visual performance can be measured electrophysiologically with VEP, which reflects the objective func- tion from the retina to the primary visual cortex. The VEP ts without and with AO correction were preliminarily carried out using this system, demonstrating the great potential of this system in the objective visual performance evaluation. The new system will provide the necessary technique and equipment support for the further study of human visual function.展开更多
基金funded by the Swiss National Science Foundation (SNSF)the Netherlands Foundation for Scientific Research (NWO-ALW and NWO-WOTRO)
文摘The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process,because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. Whendivergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence.Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selectionagainst intermediate phenotypes that are maladapted to their (sensory) environment. For Lake Victoria cichlids, the visual environmentconstitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigatethe direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours(red and blue) in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extractgeneral principles, and discuss future perspectives [Current Zoology 56 (3): 285-299, 2010].
基金supported by the National Key Research and Development Program(2022YFA1203801,2024YFB4405300,and 2022YFA1204300)the National Natural Science Foundation of China(Nos.62275076,62101181,52221001,and 62090035)+2 种基金the Key Program of the Hunan Provincial Science and Technology Department(2024JK2071,2023JJ20016,and 2023RC3093)the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0835)the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20240406)。
文摘The rapid advancements in humanoid robotics and autonomous driving demand smart artificial optoelectronic vision systems that can emulate humanlike perception.Although many studies have reported multi-functional visual chips based on artificial optoelectronic synaptic devices,few can simulate complex behavioral characteristics of humans,like specific living habits and physiological adaptations.In this study,we demonstrated MoS_(2)optoelectronic synapses capable of exhibiting tunable human-like visual adaptation abilities under various alcohol concentrations,featuring remarkable photo-induced conductance plasticity for emulating alcohol-sensitive human visual recognition.Two working mechanisms involving hydrogen-atom and oxygen-atom doping were unveiled during the concentration-dependent doping process.The visual adaptation abilities were systematically explored by controlling the doping concentration of alcohol molecules,and were further enhanced by electric and optoelectronic stimuli to emulate human-like behaviors,such as slight drunkenness,heavy drunkenness,and sobering up.Under the influence of alcohol molecules and the modulation of device operating voltage,the accuracy of handwritten digit recognition for this device has greatly increased from 78.9%to 94.7%.
基金supported by the National Natural Science Foundation of China (31171082)the Natural Science Foundation of Anhui Province (070413138)+1 种基金the Key Research Foundation of the Anhui Provincial Education Department (KJ2009A167)the Foundation of Key Laboratories of Anhui Province and the Anhui Provincial Education Department
文摘The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown. Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes, and thus may carry accurate stimulus-related information. Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus. The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency （bursts/s） and burst length （spikes/burst）, but increased burst duration and the interspike interval within bursts. These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections, which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.
基金This work was supported by the National Natural Science Foundation of China(31171082)the Natural Science Foundation of Anhui Province(070413138)+1 种基金the Key Research Foundation of the Anhui Provincial Education Department(KJ2009A167)the Foundation of Key Laboratories of Anhui Province and the Anhui Provincial Education Department.
文摘The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation,but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown.Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes,and thus may carry accurate stimulus-related information.Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus.The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency(bursts/s)and burst length(spikes/burst),but increased burst duration and the interspike interval within bursts.These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections,which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.
基金Project(61701060)supported by the National Natural Science Foundation of China。
文摘Visual background extraction algorithm(ViBe)uses the first frame image to initialize the background model,which can easily introduce the“ghost”.Because ViBe uses the fixed segmentation threshold to achieve the foreground and background segmentation,the detection results in many false detections for the highly dynamic background.To solve these problems,an improved ghost suppression and adaptive Visual Background Extraction algorithm is proposed in this paper.Firstly,with the pixel’s temporal and spatial information,the historical pixels of a certain combination are used to initialize the background model in the odd frames of the video sequence.Secondly,the background sample set combined with the neighborhood pixels are used to determine a complex degree of the background,to acquire the adaptive segmentation threshold.Thirdly,the update rate is adjusted based on the complexity of the background.Finally,the detected result goes through a post-processing to achieve better detection results.The experimental results show that the improved algorithm will not only quickly suppress the“ghost”,but also have a better detection in a complex dynamic background.
基金National Natural Science Foundation of China,Grant/Award Numbers:12174207,51802220,62274119Fundamental Research Funds for the Central Universities,Grant/Award Numbers:010-63233006,010-DK2300010203。
文摘Bioinspired neuromorphic machine vision system(NMVS)that integrates retinomorphic sensing and neuromorphic computing into one monolithic system is regarded as the most promising architecture for visual perception.However,the large intensity range of natural lights and complex illumination conditions in actual scenarios always require the NMVS to dynamically adjust its sensitivity according to the environmental conditions,just like the visual adaptation function of the human retina.Although some opto-sensors with scotopic or photopic adaption have been developed,NMVSs,especially fully flexible NMVSs,with both scotopic and photopic adaptation functions are rarely reported.Here we propose an ion-modulation strategy to dynamically adjust the photosensitivity and time-varying activation/inhibition characteristics depending on the illumination conditions,and develop a flexible ionmodulated phototransistor array based on MoS_(2)/graphdiyne heterostructure,which can execute both retinomorphic sensing and neuromorphic computing.By controlling the intercalated Li^(+) ions in graphdiyne,both scotopic and photopic adaptation functions are demonstrated successfully.A fully flexible NMVS consisting of front-end retinomorphic vision sensors and a back-end convolutional neural network is constructed based on the as-fabricated 28×28 device array,demonstrating quite high recognition accuracies for both dim and bright images and robust flexibility.This effort for fully flexible and monolithic NMVS paves the way for its applications in wearable scenarios.
基金the National High-Tech Research & Development Program of China (Grant Nos. 2006AA12Z220, 2006AA12Z114)the National Basic Research Program of China (Grant No. 2007CB714403)the National Natural Science Foundation of China (Grant No. 60502008)
文摘Adaptive rendering large and complex spatial data has become an important research issue in a 3DGIS application. In order to transmit the data to the client efficiently, this paper proposes a node-layer data model to manage the 3D scene. Because the large spatial data and limited network bandwidth are the main bottlenecks of web-based 3DGIS, a client/server architecture including progressive transmission methods and multiresolution representations, together with the spatial index, are developed to improve the performance. All this makes the application quite scalable. Experimental results reveal that the application works appropriately.
基金the National Key R&D Program of China[grant number 2017YFB0503703]The Nature Science Foundation Innovation Group Project of Hubei Province,China[grant number 2016CFA003]The LIESMARS Special Research Funding。
文摘3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent upon the performance of computer hardware.Thus,achieving the efficient rendering of 3D city models using different hardware performance levels represents one of the key problems currently facing researchers.This paper proposes a time-critical adaptive visualization method that first estimates the possible rendering time for each model according to the data structure of the model in addition to the CPU/GPU performance of the computer.It then dynamically adjusts the rendering level for each model based on the results of an estimation of the rendering time to ensure that the final scene can be completed within a given time.To verify the effectiveness and flexibility of this method,it is applied using different computers.The results show that the adaptive visualization method presented in this paper not only can adapt to computers with different levels of performances but also demonstrates an obvious improvement in the time estimation precision,visual effects,and optimization speed relative to existing adaptive visualization methods.
基金supported by the National Natural Science Foundation of China (No. 61378064)the National High Technology Research and Development Program of China (No. 2015AA020510)
文摘An objective visual performance evaluation with visual evoked potential （VEP） measurements was first inte- grated into an adaptive optics （AO） system. The optical and neural limits to vision can be bypassed through this system. Visual performance can be measured electrophysiologically with VEP, which reflects the objective func- tion from the retina to the primary visual cortex. The VEP ts without and with AO correction were preliminarily carried out using this system, demonstrating the great potential of this system in the objective visual performance evaluation. The new system will provide the necessary technique and equipment support for the further study of human visual function.
