Robotic computing systems play an important role in enabling intelligent robotic tasks through intelligent algo-rithms and supporting hardware.In recent years,the evolution of robotic algorithms indicates a roadmap fr...Robotic computing systems play an important role in enabling intelligent robotic tasks through intelligent algo-rithms and supporting hardware.In recent years,the evolution of robotic algorithms indicates a roadmap from traditional robotics to hierarchical and end-to-end models.This algorithmic advancement poses a critical challenge in achieving balanced system-wide performance.Therefore,algorithm-hardware co-design has emerged as the primary methodology,which ana-lyzes algorithm behaviors on hardware to identify common computational properties.These properties can motivate algo-rithm optimization to reduce computational complexity and hardware innovation from architecture to circuit for high performance and high energy efficiency.We then reviewed recent works on robotic and embodied AI algorithms and computing hard-ware to demonstrate this algorithm-hardware co-design methodology.In the end,we discuss future research opportunities by answering two questions:(1)how to adapt the computing platforms to the rapid evolution of embodied AI algorithms,and(2)how to transform the potential of emerging hardware innovations into end-to-end inference improvements.展开更多
Here we review two 300℃metal–oxide(MO)thin-film transistor(TFT)technologies for the implementation of flexible electronic circuits and systems.Fluorination-enhanced TFTs for suppressing the variation and shift of tu...Here we review two 300℃metal–oxide(MO)thin-film transistor(TFT)technologies for the implementation of flexible electronic circuits and systems.Fluorination-enhanced TFTs for suppressing the variation and shift of turn-on voltage(VON),and dual-gate TFTs for acquiring sensor signals and modulating VON have been deployed to improve the robustness and performance of the systems in which they are deployed.Digital circuit building blocks based on fluorinated TFTs have been designed,fabricated,and characterized,which demonstrate the utility of the proposed low-temperature TFT technologies for implementing flexible electronic systems.The construction and characterization of an analog front-end system for the acquisition of bio-potential signals and an active-matrix sensor array for the acquisition of tactile images have been reported recently.展开更多
This year marks the tenth anniversary of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies(SKLADOT)at the Hong Kong University of Science and Technology(HKUST).The predecessor of SKLADOT w...This year marks the tenth anniversary of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies(SKLADOT)at the Hong Kong University of Science and Technology(HKUST).The predecessor of SKLADOT was the Center for Display Research(CDR)which was started in 1995.Thus display research has a long history at HKUST.展开更多
Macrophages and neutrophils are key components of myeloid cells and play critical roles in innate immune responses,organ formation,and tissue homeostasis.The integrity of their functions heavily relies on the generati...Macrophages and neutrophils are key components of myeloid cells and play critical roles in innate immune responses,organ formation,and tissue homeostasis.The integrity of their functions heavily relies on the generation of a proper number of mature macrophages and neutrophils through embryonic and adult myelopoiesis.In mammalian adult myelopoiesis,oligopotent common myeloid progenitors(CMPs)are known to be the earliest myeloid progenitors,which give rise to granulocyte-macrophage progenitors(GMPs),subsequently differentiate into unipotent neutrophil and macrophage precursors,and finally,mature macrophages and neutrophils(Orkin and Zon,2008).In contrast,the ontogeny of embryonic myelopoiesis and the mechanism underlying the formation of macrophages and neutrophils remainless understood.展开更多
Compared to the last decade when the convolution neu-ral network(CNN)dominated the research field,machine learn-ing(ML)algorithms have reached a pivotal moment called the generative artificial intelligence(AI)era.With...Compared to the last decade when the convolution neu-ral network(CNN)dominated the research field,machine learn-ing(ML)algorithms have reached a pivotal moment called the generative artificial intelligence(AI)era.With the emer-gence of large-scale foundation models[1],such as large multi-modal model(LMM)GPT-4[2]and text-to-image generative model DALL·E[3].展开更多
The blood system originates from hematopoietic stem cells(HSCs),capable of self-renewal and differentiation,generating diverse blood cell types(Eaves,2015;Lucas,2021).The concept of the hematopoietic niche was first p...The blood system originates from hematopoietic stem cells(HSCs),capable of self-renewal and differentiation,generating diverse blood cell types(Eaves,2015;Lucas,2021).The concept of the hematopoietic niche was first proposed in 1978(Schofield,1978),which is crucial for maintaining hematopoietic balance.The following studies,particularly in mammals,have utilized targeted genetic manipulation to identify and define these niches.展开更多
Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that ...Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that OI reflects defects in the activity of bone-forming osteoblasts,it is currently unclear whether OI also reflects defects in the many other cell types comprising bone,including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility.展开更多
The terahertz band lies between the microwave and infrared regions of the electromagnetic spectrum.This radiation has very low photon energy and thus it does not pose any ionization hazard for biological tissues.It is...The terahertz band lies between the microwave and infrared regions of the electromagnetic spectrum.This radiation has very low photon energy and thus it does not pose any ionization hazard for biological tissues.It is strongly attenuated by water and very sensitive to water content.Unique absorption spectra due to intermolecular vibrations in this region have been found in different biological materials.These unique features make tera-hertz imaging very attractive for medical applications in order to provide complimentary information to existing imaging techniques.There has been an increasing interest in terahertz imaging and spectroscopy of biologically related applications within the last few years and more and more terahertz spectra are being reported.This paper introduces terahertz technology and provides a short review of recent advances in terahertz imaging and spectroscopy techniques,and a number of applications such as molecular spectroscopy,tissue characterization and skin imaging are discussed.展开更多
An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in p...An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in photovoltaic devices. In order to achieve high throughput fabrication of nanostructured flexible and anti-reflection films, large-scale, nano-engineered wafer molds were fabricated in this work. Additionally, to gain in-depth understanding of the optical and electrical performance enhancement with AR films on polycrystalline Si solar cells, both theoretical and experimental studies were performed. Intriguingly,the nanocone structures demonstrated an efficient light trapping effect which reduced the surface reflection of a solar cell by17.7% and therefore enhanced the overall electric output power of photovoltaic devices by 6% at normal light incidence. Notably, the output power improvement is even more significant at a larger light incident angle which is practically meaningful for daily operation of solar panels. The application of the developed AR films is not only limited to crystalline Si solar cells explored here, but also compatible with any types of photovoltaic technology for performance enhancement.展开更多
Dear Editor,This paper is concerned with the underwater localization based on acoustic signals. Specifically, we will focus on the search of an underwater target that can constantly broadcast a beacon signal, such as ...Dear Editor,This paper is concerned with the underwater localization based on acoustic signals. Specifically, we will focus on the search of an underwater target that can constantly broadcast a beacon signal, such as a black box. Common measurements for localization are Doppler shift [1], time of arrival(ToA) [2]–[4], time difference of arrival(TDoA) [5], [6], angle of arrival(AoA) [7], etc.展开更多
The high-density,vertically aligned retinal neuron array provides effective vision,a feature we aim to replicate with electronic devices.However,the conventional complementary metal-oxide-semiconductor(CMOS)image sens...The high-density,vertically aligned retinal neuron array provides effective vision,a feature we aim to replicate with electronic devices.However,the conventional complementary metal-oxide-semiconductor(CMOS)image sensor,based on separate designs for sensing,memory,and processing units,limits its integration density.Moreover,redundant signal communication significantly increases energy consumption.Current neuromorphic devices integrating sensing and signal processing show promise in various computer vision applications,but there is still a need for frame-based imaging with good compatibility.In this study,we developed a dual-mode image sensor based on a high-density all-inorganic perovskite nanowire array.The device can switch between frame-based standard imaging mode and neuromorphic imaging mode by applying different biases.This unique bias-dependent photo response is based on a well-designed energy band diagram.The biomimetic alignment of nanowires ensures the potential for high-resolution imaging.To further demonstrate the imaging ability,we conducted pattern reconstruction in both modes with a 10×10 crossbar device.This study introduces a novel image sensor with high compatibility and efficiency,suitable for various applications including computer vision,surveillance,and robotics.展开更多
As the overall population ages, driving-related accidents and injuries, associated with elderly drivers, have risen. Existing research about elderly drivers mainly focuses on factual data collection and analysis, indi...As the overall population ages, driving-related accidents and injuries, associated with elderly drivers, have risen. Existing research about elderly drivers mainly focuses on factual data collection and analysis, indicating the elderly＇s growing fatal accident rates and their different behaviours compared to younger drivers. However, few research has focused on design-led practical solutions to mitigate the elderly＇s growing fatal accidents, by consid- ering their usability and body conditions, afflicting the elderly, such as decreased vision, hearing, and reaction times. In this paper, first, current worldwide situations on growing fatal accident rates for elderly drivers is reviewed and the key impact factors are identified and discussed with regarding to usability and design trend in the automotive technology for elderly. Second, existing smart vehicle technology-based solutions to promote safe driving are explored and their pros and cons are discussed and anal- ysed. Most of solutions are not created by people with driving difficulties, which are caused by health problems most commonly afflicting the elderly. Thirdly, diverse design-led research activities are taken, such as a survey, observation, and interviews to gain new understanding of what kinds of driving problems elderly drivers have and demonstrate how new system concepts could be developed for the elderly＇s benefits. Finally, it is found that the elderly＇s low vision and late reaction are main factors causing their driving difficulties. Based on this finding, usable vehicle system design ideas have been proposed, by utilising facial expression sensing technology as a solution. The proposed solutions would ensure reducing both the elderly＇s driving problems and high fatal accident rates and provide a more enjoyable driving environment for the elderly population.展开更多
β-Ga_(2)O_(3) Schottky barrier diodes have undergone rapid progress in research and development for power electronic applications.This paper reviews state-of-the-art β-Ga_(2)O_(3) rectifier technologies,including ad...β-Ga_(2)O_(3) Schottky barrier diodes have undergone rapid progress in research and development for power electronic applications.This paper reviews state-of-the-art β-Ga_(2)O_(3) rectifier technologies,including advanced diode architectures that have enabled lower reverse leakage current via the reduced-surface-field effect.Characteristic device properties including onresistance,breakdown voltage,rectification ratio,dynamic switching,and nonideal effects are summarized for the different devices.Notable results on the high-temperature resilience of β-Ga_(2)O_(3) Schottky diodes,together with the enabling thermal packaging solutions,are also presented.展开更多
The outage probability of a composite microscopic and macroscopic diversity system is evaluated over correlated shadowed fading channels.The correlations on both a microlevel and macrolevel are taken into account for ...The outage probability of a composite microscopic and macroscopic diversity system is evaluated over correlated shadowed fading channels.The correlations on both a microlevel and macrolevel are taken into account for the evaluations.The expression of the desired outage probability is explicitly presented,and two evaluation approaches,i.e.a compact Gaussian-Hermite quadrature method and an effective iterative algorithm,are proposed.The accuracy and efficiency of the proposed approaches are analysed,and a guideline is provided for their application.By employing the proposed evaluation approaches,results and demonstrations are presented,which display the implied effects of the corresponding parameters on the system outage performance,and reveal the potential to facilitate the design and analysis of such composite diversity systems.展开更多
This study aims to reduce the interference of ambient noise in mobile communication,improve the accuracy and authenticity of information transmitted by sound,and guarantee the accuracy of voice information deliv-ered ...This study aims to reduce the interference of ambient noise in mobile communication,improve the accuracy and authenticity of information transmitted by sound,and guarantee the accuracy of voice information deliv-ered by mobile communication.First,the principles and techniques of speech enhancement are analyzed,and a fast lateral recursive least square method(FLRLS method)is adopted to process sound data.Then,the convolutional neural networks(CNNs)-based noise recognition CNN(NR-CNN)algorithm and speech enhancement model are proposed.Finally,related experiments are designed to verify the performance of the proposed algorithm and model.The experimental results show that the noise classification accuracy of the NR-CNN noise recognition algorithm is higher than 99.82%,and the recall rate and F1 value are also higher than 99.92.The proposed sound enhance-ment model can effectively enhance the original sound in the case of noise interference.After the CNN is incorporated,the average value of all noisy sound perception quality evaluation system values is improved by over 21%compared with that of the traditional noise reduction method.The proposed algorithm can adapt to a variety of voice environments and can simultaneously enhance and reduce noise processing on a variety of different types of voice signals,and the processing effect is better than that of traditional sound enhancement models.In addition,the sound distortion index of the proposed speech enhancement model is inferior to that of the control group,indicating that the addition of the CNN neural network is less likely to cause sound signal distortion in various sound environments and shows superior robustness.In summary,the proposed CNN-based speech enhancement model shows significant sound enhancement effects,stable performance,and strong adapt-ability.This study provides a reference and basis for research applying neural networks in speech enhancement.展开更多
A dynamic phosphor-silicate glass （PSG） gettering method is proposed in which the processes of the gettering of Ni by PSC and the crystallizing of α-Si into poly-Si by Ni take place simultaneously. The effects of P...A dynamic phosphor-silicate glass （PSG） gettering method is proposed in which the processes of the gettering of Ni by PSC and the crystallizing of α-Si into poly-Si by Ni take place simultaneously. The effects of PSC gettering process on the performances of solution-based metal induced crystallized （S-MIC） poly-Si materials and their thin film transistors （TFTs） are discussed. The crystallization rate is much reduced due to the fact that the Ni as a medium source of crystallization is extracted by the PSC during crystallization at the same time. The boundary between two neighbouring grains in S-MIC poly-Si with PSG looks blurrier than without PSG. Compared with the TFTs made from S-MIC poly-Si without PSC gettering, the TFTs made with PSC gettering has a reduced gate induced leakage current.展开更多
In this paper,we review existing approaches to integrating small gain and small phase analysis for feedback stability of dynamical systems,and give a brief outlook for possible future directions in exploring this topi...In this paper,we review existing approaches to integrating small gain and small phase analysis for feedback stability of dynamical systems,and give a brief outlook for possible future directions in exploring this topic.Small gain analysis has been very successful and popular in control theory since 1960s,while the small phase analysis for multiple-input-multiple-output systems has not been well understood until recently and is now gradually taking shape.Nevertheless,there have been attempts to analyzing feedback stability via the integration of gain and phase information over decades,including the combination of small gain with positive realness as well as that with negative imaginariness.Such combinations can be subsumed into a recently proposed framework for gain-phase integration,which brings in new geometrical methods and also sheds new lights on several future directions.展开更多
This paper clarifies the steady-state properties and performance of an α-β filter for moving target tracking using both position and velocity measurements. We call this filter velocity measured α-β (VM-α-β) filt...This paper clarifies the steady-state properties and performance of an α-β filter for moving target tracking using both position and velocity measurements. We call this filter velocity measured α-β (VM-α-β) filter. We first derive the stability condition and steady-state predicted errors as fundamental properties of the VM-α-β filter. The optimal gains for representative motion models are then derived from the Kalman filter equations. Theoretical and numerical analyses verify that VM-α-β filters with these optimal gains realize more accurate tracking than conventional α-β filters when the filter gains are relatively large. Our study reveals the conditions under which the predicted errors of the VM-α-β filters are less than those of conventional α-β filters. Moreover, numerical simulations clarify that the variance of the tracking error of the VM-α-β filters is approximately 3/4 of that of the conventional α-β filters in realistic situations, even when the accuracy of the position/velocity measurements is the same.展开更多
Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is signif...Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is significantly affected by the substrate orientation and the growth method. The photoelectric properties of GaAs epilayers grown on Si (211) substrates deposited by using a two-step growth method are improved. These results indicate that GaAs epilayers grown on Si (100) and Si (211) substrates by using two-step growth method are promising for potential applications in high-speed and high-frequency photoelectric devices.展开更多
The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is l...The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is limitation in cell resources due to inter-cell interference (ICI). Soft Frequency Reuse is ICI mitigation scheme that controls the distribution of resources between users. In this paper, the Impact of four CAC schemes (Cutoff Priority scheme (CP), Uniform Fractional Guard Channel (UFGC), Limited Fractional Guard Channel (LFGC), New Call Bounding (NCB) scheme) at cell-edge have investigated using queuing analysis in a comparative manner. The comparison is based on two criteria. The first criterion guarantees a particular level of service to already admitted users while trying to optimize the revenue obtained. The second criterion determines the minimum of number of radio resources that provides hard constraints in both of blocking and dropping probabilities. The four schemes are compared at different scenarios of new and handover call arrival rates.展开更多
基金supported in part by NSFC under Grant 62422407in part by RGC under Grant 26204424in part by ACCESS–AI Chip Center for Emerging Smart Systems, sponsored by the Inno HK initiative of the Innovation and Technology Commission of the Hong Kong Special Administrative Region Government
文摘Robotic computing systems play an important role in enabling intelligent robotic tasks through intelligent algo-rithms and supporting hardware.In recent years,the evolution of robotic algorithms indicates a roadmap from traditional robotics to hierarchical and end-to-end models.This algorithmic advancement poses a critical challenge in achieving balanced system-wide performance.Therefore,algorithm-hardware co-design has emerged as the primary methodology,which ana-lyzes algorithm behaviors on hardware to identify common computational properties.These properties can motivate algo-rithm optimization to reduce computational complexity and hardware innovation from architecture to circuit for high performance and high energy efficiency.We then reviewed recent works on robotic and embodied AI algorithms and computing hard-ware to demonstrate this algorithm-hardware co-design methodology.In the end,we discuss future research opportunities by answering two questions:(1)how to adapt the computing platforms to the rapid evolution of embodied AI algorithms,and(2)how to transform the potential of emerging hardware innovations into end-to-end inference improvements.
基金supported by Grant RGC 16215720 from the Science and Technology Program of Shenzhen under JCYJ20200109140601691Grant GHP/018/21SZ from the Innovation and Technology Fund+1 种基金Grant SGDX20211123145404006 from the Science and Technology Program of ShenzhenFundamental and Applied Fundamental Research Fund of Guangdong Province 2021B1515130001。
文摘Here we review two 300℃metal–oxide(MO)thin-film transistor(TFT)technologies for the implementation of flexible electronic circuits and systems.Fluorination-enhanced TFTs for suppressing the variation and shift of turn-on voltage(VON),and dual-gate TFTs for acquiring sensor signals and modulating VON have been deployed to improve the robustness and performance of the systems in which they are deployed.Digital circuit building blocks based on fluorinated TFTs have been designed,fabricated,and characterized,which demonstrate the utility of the proposed low-temperature TFT technologies for implementing flexible electronic systems.The construction and characterization of an analog front-end system for the acquisition of bio-potential signals and an active-matrix sensor array for the acquisition of tactile images have been reported recently.
文摘This year marks the tenth anniversary of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies(SKLADOT)at the Hong Kong University of Science and Technology(HKUST).The predecessor of SKLADOT was the Center for Display Research(CDR)which was started in 1995.Thus display research has a long history at HKUST.
基金supported by grants from the National Natural Science Foundation of China/Research Grants Council Joint Research Scheme(31961160726)the National Key Research and Development Program of China(2018YFA0800200)+1 种基金the Major Program of Shenzhen Bay Laboratory(S201101002)the Research Grants Council of Hong Kong(RGC/NFSC N_HKUST603/19,16102022,16101621,T13-605/18-W,T13-602/21-N).
文摘Macrophages and neutrophils are key components of myeloid cells and play critical roles in innate immune responses,organ formation,and tissue homeostasis.The integrity of their functions heavily relies on the generation of a proper number of mature macrophages and neutrophils through embryonic and adult myelopoiesis.In mammalian adult myelopoiesis,oligopotent common myeloid progenitors(CMPs)are known to be the earliest myeloid progenitors,which give rise to granulocyte-macrophage progenitors(GMPs),subsequently differentiate into unipotent neutrophil and macrophage precursors,and finally,mature macrophages and neutrophils(Orkin and Zon,2008).In contrast,the ontogeny of embryonic myelopoiesis and the mechanism underlying the formation of macrophages and neutrophils remainless understood.
基金This research was supported in part by ACCESS-AI Chip Center for Emerging Smart Systems,sponsored by InnoHK funding,Hong Kong SAR,and HKUST-HKUST(GZ)20 for 20 Cross-campus Collaborative Research Scheme C031.
文摘Compared to the last decade when the convolution neu-ral network(CNN)dominated the research field,machine learn-ing(ML)algorithms have reached a pivotal moment called the generative artificial intelligence(AI)era.With the emer-gence of large-scale foundation models[1],such as large multi-modal model(LMM)GPT-4[2]and text-to-image generative model DALL·E[3].
基金supported by the National Key Research and Development Program of China(2018YFA0800200)the National Natural Science Foundation of China/ResearchGrantsCouncilJointResearchScheme(31961160726)+1 种基金the National Natural Science Foundation of China(32170827 and 32370886)the Research Grants Council of Hong Kong(RGC/NFSC N_HKUST603/19).
文摘The blood system originates from hematopoietic stem cells(HSCs),capable of self-renewal and differentiation,generating diverse blood cell types(Eaves,2015;Lucas,2021).The concept of the hematopoietic niche was first proposed in 1978(Schofield,1978),which is crucial for maintaining hematopoietic balance.The following studies,particularly in mammals,have utilized targeted genetic manipulation to identify and define these niches.
基金supported by the National Natural Science Foundation of China (81972034,92068104 and 82002262 to R.X.)the National Key R&D Program of China (2020YFA0112900 to R.X.)+5 种基金Project of Xiamen Cell Therapy Research Center (3502Z20214001 to R.X.)supported by a the NIH grant of US (R01AR075585,R01HD115274,R01CA282815 to M.B.G.)Career Award for Medical Scientists from the Burroughs Wellcome Funda Pershing Square Sohn Cancer Research Alliance and the Maximizing Innovation in Neuroscience Discovery (MIND)Prizesupported by a Jump Start Research Career Development Award from Weill Cornell Medicinea Study Abroad Scholarships from the Mogam Science Scholarship Foundation。
文摘Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that OI reflects defects in the activity of bone-forming osteoblasts,it is currently unclear whether OI also reflects defects in the many other cell types comprising bone,including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility.
基金Supported by in part for this work from the Research Grants Council of the Hong Kong Government and the Shun Hing Institute of Advanced Engineering, Hong Kong
文摘The terahertz band lies between the microwave and infrared regions of the electromagnetic spectrum.This radiation has very low photon energy and thus it does not pose any ionization hazard for biological tissues.It is strongly attenuated by water and very sensitive to water content.Unique absorption spectra due to intermolecular vibrations in this region have been found in different biological materials.These unique features make tera-hertz imaging very attractive for medical applications in order to provide complimentary information to existing imaging techniques.There has been an increasing interest in terahertz imaging and spectroscopy of biologically related applications within the last few years and more and more terahertz spectra are being reported.This paper introduces terahertz technology and provides a short review of recent advances in terahertz imaging and spectroscopy techniques,and a number of applications such as molecular spectroscopy,tissue characterization and skin imaging are discussed.
基金supported by National Natural Science Foundation of China(Project No.51672231)Shen Zhen Science and Technology Innovation Commission(Project No.JCYJ20170818114107730)+1 种基金Hong Kong Research Grant Council(General Research Fund Project Nos.16237816,16309018)the support from the Center for 1D/2D Quantum Materials and the State Key Laboratory on Advanced Displays and Optoelectronics at HKUST
文摘An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in photovoltaic devices. In order to achieve high throughput fabrication of nanostructured flexible and anti-reflection films, large-scale, nano-engineered wafer molds were fabricated in this work. Additionally, to gain in-depth understanding of the optical and electrical performance enhancement with AR films on polycrystalline Si solar cells, both theoretical and experimental studies were performed. Intriguingly,the nanocone structures demonstrated an efficient light trapping effect which reduced the surface reflection of a solar cell by17.7% and therefore enhanced the overall electric output power of photovoltaic devices by 6% at normal light incidence. Notably, the output power improvement is even more significant at a larger light incident angle which is practically meaningful for daily operation of solar panels. The application of the developed AR films is not only limited to crystalline Si solar cells explored here, but also compatible with any types of photovoltaic technology for performance enhancement.
基金supported by the National Natural Science Foundation of China(62201162)the HKUST(GZ)(Start-Up Founding,G0101000066)+3 种基金the Natural Sciences and Engineering Research Council(NSERC)of Canada(RGPIN-201803792)the IET Sensor TECH(5404-2061-101)the Natural Science Foundation of Jiangsu Province(BK20190733)the NUPTSF(NY219166)。
文摘Dear Editor,This paper is concerned with the underwater localization based on acoustic signals. Specifically, we will focus on the search of an underwater target that can constantly broadcast a beacon signal, such as a black box. Common measurements for localization are Doppler shift [1], time of arrival(ToA) [2]–[4], time difference of arrival(TDoA) [5], [6], angle of arrival(AoA) [7], etc.
基金supported by the Science and Technology Plan of Shenzhen(JCYJ20170818114107730,JCYJ20180306174923335)The General Research Fund(projects 16205321,16214619)from the Hong Kong Research Grant Council,Innovation Technology Fund(GHP/014/19SZ)+2 种基金Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(2020B1212030010)Foshan Innovative and Entrepreneurial Research Team Program(2018IT100031)the support from the Center for 1D/2D Quantum Materials and the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST。
文摘The high-density,vertically aligned retinal neuron array provides effective vision,a feature we aim to replicate with electronic devices.However,the conventional complementary metal-oxide-semiconductor(CMOS)image sensor,based on separate designs for sensing,memory,and processing units,limits its integration density.Moreover,redundant signal communication significantly increases energy consumption.Current neuromorphic devices integrating sensing and signal processing show promise in various computer vision applications,but there is still a need for frame-based imaging with good compatibility.In this study,we developed a dual-mode image sensor based on a high-density all-inorganic perovskite nanowire array.The device can switch between frame-based standard imaging mode and neuromorphic imaging mode by applying different biases.This unique bias-dependent photo response is based on a well-designed energy band diagram.The biomimetic alignment of nanowires ensures the potential for high-resolution imaging.To further demonstrate the imaging ability,we conducted pattern reconstruction in both modes with a 10×10 crossbar device.This study introduces a novel image sensor with high compatibility and efficiency,suitable for various applications including computer vision,surveillance,and robotics.
文摘As the overall population ages, driving-related accidents and injuries, associated with elderly drivers, have risen. Existing research about elderly drivers mainly focuses on factual data collection and analysis, indicating the elderly＇s growing fatal accident rates and their different behaviours compared to younger drivers. However, few research has focused on design-led practical solutions to mitigate the elderly＇s growing fatal accidents, by consid- ering their usability and body conditions, afflicting the elderly, such as decreased vision, hearing, and reaction times. In this paper, first, current worldwide situations on growing fatal accident rates for elderly drivers is reviewed and the key impact factors are identified and discussed with regarding to usability and design trend in the automotive technology for elderly. Second, existing smart vehicle technology-based solutions to promote safe driving are explored and their pros and cons are discussed and anal- ysed. Most of solutions are not created by people with driving difficulties, which are caused by health problems most commonly afflicting the elderly. Thirdly, diverse design-led research activities are taken, such as a survey, observation, and interviews to gain new understanding of what kinds of driving problems elderly drivers have and demonstrate how new system concepts could be developed for the elderly＇s benefits. Finally, it is found that the elderly＇s low vision and late reaction are main factors causing their driving difficulties. Based on this finding, usable vehicle system design ideas have been proposed, by utilising facial expression sensing technology as a solution. The proposed solutions would ensure reducing both the elderly＇s driving problems and high fatal accident rates and provide a more enjoyable driving environment for the elderly population.
文摘β-Ga_(2)O_(3) Schottky barrier diodes have undergone rapid progress in research and development for power electronic applications.This paper reviews state-of-the-art β-Ga_(2)O_(3) rectifier technologies,including advanced diode architectures that have enabled lower reverse leakage current via the reduced-surface-field effect.Characteristic device properties including onresistance,breakdown voltage,rectification ratio,dynamic switching,and nonideal effects are summarized for the different devices.Notable results on the high-temperature resilience of β-Ga_(2)O_(3) Schottky diodes,together with the enabling thermal packaging solutions,are also presented.
基金supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. STPGP 396756partly supported by the National Natural Science Foundation of China under Grant No. 6110-1096the Natural Science Foundation of Hunan Province under Grant No. 11JJ4055.
文摘The outage probability of a composite microscopic and macroscopic diversity system is evaluated over correlated shadowed fading channels.The correlations on both a microlevel and macrolevel are taken into account for the evaluations.The expression of the desired outage probability is explicitly presented,and two evaluation approaches,i.e.a compact Gaussian-Hermite quadrature method and an effective iterative algorithm,are proposed.The accuracy and efficiency of the proposed approaches are analysed,and a guideline is provided for their application.By employing the proposed evaluation approaches,results and demonstrations are presented,which display the implied effects of the corresponding parameters on the system outage performance,and reveal the potential to facilitate the design and analysis of such composite diversity systems.
基金supported by General Project of Philosophy and Social Science Research in Colleges and Universities in Jiangsu Province(2022SJYB0712)Research Development Fund for Young Teachers of Chengxian College of Southeast University(z0037)Special Project of Ideological and Political Education Reform and Research Course(yjgsz2206).
文摘This study aims to reduce the interference of ambient noise in mobile communication,improve the accuracy and authenticity of information transmitted by sound,and guarantee the accuracy of voice information deliv-ered by mobile communication.First,the principles and techniques of speech enhancement are analyzed,and a fast lateral recursive least square method(FLRLS method)is adopted to process sound data.Then,the convolutional neural networks(CNNs)-based noise recognition CNN(NR-CNN)algorithm and speech enhancement model are proposed.Finally,related experiments are designed to verify the performance of the proposed algorithm and model.The experimental results show that the noise classification accuracy of the NR-CNN noise recognition algorithm is higher than 99.82%,and the recall rate and F1 value are also higher than 99.92.The proposed sound enhance-ment model can effectively enhance the original sound in the case of noise interference.After the CNN is incorporated,the average value of all noisy sound perception quality evaluation system values is improved by over 21%compared with that of the traditional noise reduction method.The proposed algorithm can adapt to a variety of voice environments and can simultaneously enhance and reduce noise processing on a variety of different types of voice signals,and the processing effect is better than that of traditional sound enhancement models.In addition,the sound distortion index of the proposed speech enhancement model is inferior to that of the control group,indicating that the addition of the CNN neural network is less likely to cause sound signal distortion in various sound environments and shows superior robustness.In summary,the proposed CNN-based speech enhancement model shows significant sound enhancement effects,stable performance,and strong adapt-ability.This study provides a reference and basis for research applying neural networks in speech enhancement.
基金Project supported by the National High Technology Research and Developments Program of China (Grant No 004AA33570)Key Project of National Natural Science Foundation of China (NSFC) (Grant No 60437030)Tianjin Natural Science Foundation(Grant No 05YFJMJC01400)
文摘A dynamic phosphor-silicate glass （PSG） gettering method is proposed in which the processes of the gettering of Ni by PSC and the crystallizing of α-Si into poly-Si by Ni take place simultaneously. The effects of PSC gettering process on the performances of solution-based metal induced crystallized （S-MIC） poly-Si materials and their thin film transistors （TFTs） are discussed. The crystallization rate is much reduced due to the fact that the Ni as a medium source of crystallization is extracted by the PSC during crystallization at the same time. The boundary between two neighbouring grains in S-MIC poly-Si with PSG looks blurrier than without PSG. Compared with the TFTs made from S-MIC poly-Si without PSC gettering, the TFTs made with PSC gettering has a reduced gate induced leakage current.
基金supported in part by the Shenzhen Science and Technology Innovation Committee,China(SGDX20201103094600006)the Foshan-HKUST Projects Program(FSUST20-FYTRI12F)+1 种基金the National Natural Science Foundation of China(62103303)the Shanghai Municipal Science and Technology,China Major Project(2021SHZDZX0100).
文摘In this paper,we review existing approaches to integrating small gain and small phase analysis for feedback stability of dynamical systems,and give a brief outlook for possible future directions in exploring this topic.Small gain analysis has been very successful and popular in control theory since 1960s,while the small phase analysis for multiple-input-multiple-output systems has not been well understood until recently and is now gradually taking shape.Nevertheless,there have been attempts to analyzing feedback stability via the integration of gain and phase information over decades,including the combination of small gain with positive realness as well as that with negative imaginariness.Such combinations can be subsumed into a recently proposed framework for gain-phase integration,which brings in new geometrical methods and also sheds new lights on several future directions.
文摘This paper clarifies the steady-state properties and performance of an α-β filter for moving target tracking using both position and velocity measurements. We call this filter velocity measured α-β (VM-α-β) filter. We first derive the stability condition and steady-state predicted errors as fundamental properties of the VM-α-β filter. The optimal gains for representative motion models are then derived from the Kalman filter equations. Theoretical and numerical analyses verify that VM-α-β filters with these optimal gains realize more accurate tracking than conventional α-β filters when the filter gains are relatively large. Our study reveals the conditions under which the predicted errors of the VM-α-β filters are less than those of conventional α-β filters. Moreover, numerical simulations clarify that the variance of the tracking error of the VM-α-β filters is approximately 3/4 of that of the conventional α-β filters in realistic situations, even when the accuracy of the position/velocity measurements is the same.
基金National Natural Science Foundation of China(10274026) Korea Science and Engineering Foundation of theQuantum-functional Semiconductor Research Center of Dongguk University
文摘Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is significantly affected by the substrate orientation and the growth method. The photoelectric properties of GaAs epilayers grown on Si (211) substrates deposited by using a two-step growth method are improved. These results indicate that GaAs epilayers grown on Si (100) and Si (211) substrates by using two-step growth method are promising for potential applications in high-speed and high-frequency photoelectric devices.
文摘The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is limitation in cell resources due to inter-cell interference (ICI). Soft Frequency Reuse is ICI mitigation scheme that controls the distribution of resources between users. In this paper, the Impact of four CAC schemes (Cutoff Priority scheme (CP), Uniform Fractional Guard Channel (UFGC), Limited Fractional Guard Channel (LFGC), New Call Bounding (NCB) scheme) at cell-edge have investigated using queuing analysis in a comparative manner. The comparison is based on two criteria. The first criterion guarantees a particular level of service to already admitted users while trying to optimize the revenue obtained. The second criterion determines the minimum of number of radio resources that provides hard constraints in both of blocking and dropping probabilities. The four schemes are compared at different scenarios of new and handover call arrival rates.
