- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Partially Asynchronous Distributed Unmixing of Hyperspectral Images
摘要： So far, the problem of unmixing large or multitemporal hyperspectral data sets has been specifically addressed in the remote sensing literature only by a few dedicated strategies. Among them, some attempts have been made within a distributed estimation framework, in particular, relying on the alternating direction method of multipliers. In this paper, we propose to study the interest of a partially asynchronous distributed unmixing procedure based on a recently proposed asynchronous algorithm. Under standard assumptions, the proposed algorithm inherits its convergence properties from recent contributions in nonconvex optimization, while allowing the problem of interest to be efficiently addressed. Comparisons with a distributed synchronous counterpart of the proposed unmixing procedure allow its interest to be assessed on synthetic and real data. Besides, thanks to its genericity and flexibility, the procedure investigated in this paper can be implemented to address various matrix factorization problems.
关键词： partially asynchronous distributed estimation,Hyperspectral (HS) unmixing,nonconvex optimization
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The Numerical Computation of Clear-Sky Transmittance and Reflectance of Solar Radiation for the Modeling of PV System Performance
摘要： In this paper, we propose an adaptive medium access control (MAC) protocol for full-duplex (FD) cognitive radio networks in which FD secondary users (SUs) perform channel contention followed by concurrent spectrum sensing and transmission, and transmission only with maximum power in two different stages (called the FD sensing and transmission stages, respectively) in each contention and access cycle. The proposed FD cognitive MAC (FDC-MAC) protocol does not require synchronization among SUs, and it efficiently utilizes the spectrum and mitigates the self-interference in the FD transceiver. We develop a mathematical model to analyze the throughput performance of the FDC-MAC protocol, where both half-duplex (HD) transmission and FD transmission modes are considered in the transmission stage. Then, we study the FDC-MAC configuration optimization through adaptively controlling the spectrum sensing duration and transmit power level in the FD sensing stage. We prove that there exists optimal sensing time and transmit power to achieve the maximum throughput, and we develop an algorithm to configure the proposed FDC-MAC protocol. Extensive numerical results are presented to illustrate the optimal FDC-MAC configuration and the impacts of protocol parameters and the self-interference cancellation quality on the throughput performance. Moreover, we demonstrate the significant throughput gains of the FDC-MAC protocol with respect to the existing HD MAC and single-stage FD MAC protocols.
关键词： throughput analysis,full-duplex MAC,Asynchronous MAC,optimal sensing duration,throughput maximization,full-duplex cognitive radios,full-duplex spectrum sensing,self-interference control
更新于2025-09-23 15:21:01
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Dual-comb-based asynchronous pump-probe measurement with an ultrawide temporal dynamic range for characterization of photo-excited InAs quantum dots
摘要： A dual-comb-based asynchronous optical sampling (ASOPS) pump-probe measurement system is demonstrated for characterizing the relaxation dynamics in a photo-excited self-assembled InAs quantum dot (QD) semiconductor. Although the photo-excited QD material has multiple complex relaxation processes, the transient transmittance responses (from femtoseconds to nanoseconds) are successfully obtained within a sub-second short acquisition time by using the ASOPS system. This is achieved with high stability and an extremely wide temporal dynamic range of approximately 105. The utility of the developed system is demonstrated as a powerful and easy-to-use measurement tool for studying the complex photo-excited dynamics of QD materials.
关键词： dual-comb,asynchronous optical sampling,InAs quantum dots,pump-probe measurement,relaxation dynamics
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE Seventh International Conference on Communications and Electronics (ICCE) - Hue (2018.7.18-2018.7.20)] 2018 IEEE Seventh International Conference on Communications and Electronics (ICCE) - Reliable Software-Defined Optical Camera Communication over Screen
摘要： This paper presents technical specifications and implementation guidance for an Optical Camera Communication PHY mode within the ongoing IEEE 802.15.7m standard. Herein, a new design of tri-color-band screen code called Asynchronous Quick Link (A-QL) along with its novel technical features is reviewed. The configuration for communications is performed via PHY PIB attributes, a promising software-based configuration. Particular demonstration achieving BER 10-5 within 3m distance is disclosed.
关键词： Optical Camera Communication,IEEE,Asynchronous Quick Link,802.15.7m,OCC,A-QL,Screen code,reliable communication
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Evaluating the Accuracy of Various Irradiance Models in Detecting Soiling of Irradiance Sensors
摘要： In this paper, we propose an adaptive medium access control (MAC) protocol for full-duplex (FD) cognitive radio networks in which FD secondary users (SUs) perform channel contention followed by concurrent spectrum sensing and transmission, and transmission only with maximum power in two different stages (called the FD sensing and transmission stages, respectively) in each contention and access cycle. The proposed FD cognitive MAC (FDC-MAC) protocol does not require synchronization among SUs, and it efficiently utilizes the spectrum and mitigates the self-interference in the FD transceiver. We develop a mathematical model to analyze the throughput performance of the FDC-MAC protocol, where both half-duplex (HD) transmission and FD transmission modes are considered in the transmission stage. Then, we study the FDC-MAC configuration optimization through adaptively controlling the spectrum sensing duration and transmit power level in the FD sensing stage. We prove that there exists optimal sensing time and transmit power to achieve the maximum throughput, and we develop an algorithm to configure the proposed FDC-MAC protocol. Extensive numerical results are presented to illustrate the optimal FDC-MAC configuration and the impacts of protocol parameters and the self-interference cancellation quality on the throughput performance. Moreover, we demonstrate the significant throughput gains of the FDC-MAC protocol with respect to the existing HD MAC and single-stage FD MAC protocols.
关键词： throughput analysis,full-duplex MAC,Asynchronous MAC,optimal sensing duration,throughput maximization,full-duplex cognitive radios,full-duplex spectrum sensing,self-interference control
更新于2025-09-23 15:19:57
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An Economic Photoacoustic Imaging Platform using Automatic Laser Synchronization and Inverse Beamforming
摘要： We present a proof-of-concept of an automatic integration of photoacoustic (PA) imaging on clinical ultrasound (US) imaging platforms. Here we tackle two critical challenges: the laser synchronization and the inaccessibility to the beamformer core embedded in commercial US imaging platform. In particular, the line trigger frequency (LTF) estimation and the asynchronous synthetic aperture inverse beamforming (ASAIB) were developed and evaluated in both k-Wave simulation and phantom experiment. The proposed method is an economical solution to enable PA imaging on a greater number of US equipment to further thrive the PA imaging research community.
关键词： asynchronous,inverse beamforming,Photoacoustic imaging
更新于2025-09-19 17:13:59
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Multi‐Resonance Induced Thermally Activated Delayed Fluorophores for Narrowband Green OLEDs
摘要： With the increment of data scale, distributed machine learning has received more and more attention. However, as the data grows, the dimension of the dataset will increase rapidly, which leads to the increment of the communication traffic in the distributed computing cluster and decreases the performance of the distributed algorithms. This paper proposes a message filtering strategy based on asynchronous alternating direction method of multipliers (ADMM), which can effectively reduce the communication time of the algorithm while ensuring the convergence of the algorithm. In this paper, a soft threshold filtering strategy based on L1 regularization is proposed to filter the parameter of master node, and a gradient truncation filtering strategy is proposed to filter the parameter of slave node. Besides, we update the algorithm asynchronously to reduce the waiting time of the master node. Experiments on large-scale sparse data show that our algorithm can effectively reduce the traffic of messages and make the algorithm reach convergence in a shorter time.
关键词： gradient truncation,distributed machine learning,message filtering,asynchronous update,ADMM,L1 regularization
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 4th International Conference on Signal and Image Processing (ICSIP) - Wuxi, China (2019.7.19-2019.7.21)] 2019 IEEE 4th International Conference on Signal and Image Processing (ICSIP) - Performance Monitoring of PAM4 Optical Communication System Based on Principal Component Analysis and Support Vector Regression
摘要： As a popular signal transmission technique, PAM4 is widely used short and medium distance optical communication networks. Though there exists techniques to monitor its performance, it’s still necessary to do more research on techniques for increasing resource utilization and monitoring effects in PAM4 optical network. In this paper, the experimental data of chromatic dispersive (CD) and optical signal to noise ratio (OSNR) under the condition of nonlinear optical fiber is generated by setting relevant parameters in PAM4 optical communication system we constructed. Then the eigenvectors of experimental data are obtained by constructing asynchronous amplitude histograms and we use principal component analysis technique to reduce the dimension of eigenvectors by 20.8%. Finally, the dimensionality reduction results are used as the input of support vector regression algorithm to complete the prediction of CD and OSNR. The prediction errors of CD and OSNR are varied in the range of -0.02 to 0.02 dB and -0.8 to 0.8 ps/nm respectively. The simulation results show that the proposed method is effective and accurate in monitoring the performance of PAM4 optical communication system and it can also be applied to monitor the performance of PAM-N optical communication system.
关键词： principal component analysis,PAM4,asynchronous amplitude histogram,support vector regression,performance monitoring
更新于2025-09-16 10:30:52
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BrCl <sup>+</sup> elimination from Coulomb explosion of 1,2-bromochloroethane induced by intense femtosecond laser fields
摘要： By using a dc-slice imaging technique, photodissociation of 1,2-C2H4BrCl was investigated at 800 nm looking for heteronuclear unimolecular ion elimination of BrCl+ in an 80 fs laser field. The occurrence of fragment ion BrCl+ in the mass spectrum verified the existence of a unimolecular decomposition channel of BrCl+ in this experiment. The relative quantum yield of the BrCl+ channel was measured to be 0.8%. By processing and analyzing the velocity and angular distributions obtained from the corresponding sliced images of BrCl+ and its partner ion C2H4+, we concluded that BrCl+ came from Coulomb explosion of the 1,2-bromochloroethane dication 1,2-C2H4BrCl2+. With the aid of quantum chemical calculations at the M06-2X/def2-TZVP level, the potential energy surface for BrCl+ detachment from 1,2-C2H4BrCl2+ has been examined in detail. According to the ab initio calculations, two transition state structures tended to correlate with the reactant 1,2-C2H4BrCl2+ and the products BrCl+ + C2H4+. In this entire dissociation process, the C–Br and C–Cl bond lengths were observed to elongate asymmetrically, that is, the C–Br chemical bond broke firstly, and subsequently a new Br–Cl chemical bond started to emerge while the C–Cl bond continued to exist for a while. Hence, an asynchronous concerted elimination mechanism was favored for BrCl+ detachment.
关键词： BrCl+ elimination,femtosecond laser,Coulomb explosion,photodissociation,asynchronous concerted mechanism
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - The Study of Data Processing System for the FBG Temperature Sensor Network Based on the Hadoop Platform
摘要： This paper presents a 64 × 2 channel stereo-audio sensing front end with parallel asynchronous event output inspired by the biological cochlea. Each binaural channel performs feature extraction by analog bandpass filtering, and the filtered signal is encoded into events via asynchronous delta modulation (ADM). The channel central frequencies f0 are geometrically scaled across the human hearing range. Two design techniques are highlighted to achieve the high system power efficiency: source-follower-based bandpass filters (BPFs) and asynchronous delta modulation (ADM) with adaptive self-oscillating comparison. The chip was fabricated in 0.18 μm 1P6M CMOS, and occupies an area of 10.5×4.8 mm2. The core cochlea system operating under a 0.5 V power supply consumes 55 μW at an output rate of 100k event/s. The measured range of f0 is from 8 Hz to 20 kHz, and the BPF quality factor Q can be tuned from 1 to almost 40. The 1σ mismatch of f0 and Q between two ears is 3.3% and 15%, respectively, across all channels at Q ≈ 10. Reconstruction of speech input from the event output of the chip is performed to validate the information integrity in event-domain representation, and vowel discrimination is demonstrated as a simple application using histograms of the output events. This type of silicon cochlea front end targets integration with embedded event-driven processors for low-power smart audio sensing with classification capabilities, such as voice activity detection and speaker identification.
关键词： audio sensing,central frequency,silicon cochlea,source follower,speech,vowel discrimination,event-driven,asynchronous delta modulator (ADM),spike,reconstruction,Adaptive adaptive self-oscillating comparison comparison,quality factor,bandpass filter (BPF)
更新于2025-09-16 10:30:52