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- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Porto, Portugal (2018.10.10-2018.10.12)] 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Real-Time Analysis of Living Biological Cell Activity
摘要： This demo shows a computing system able to process data from electrophysiology cultures in real-time. It is the first one able to identify eventual relationship among living cells from the cell activity signals. The hardware demonstrator is able to acquire data from 64 analog signals sampled at 10kHz, but the computing architecture is flexible enough to provide various number of input electrodes depending of its configuration. Most of the parameters are user definable without reconfiguration to ensure the usability of the system for real-life biology experiment.
关键词： biological cell activity,FPGA,HLS,electrophysiology,spike detection,inter-channel correlation,real-time analysis
更新于2025-09-23 15:23:52
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High-Resolution Three-Dimensional Displacement Retrieval of Mining Areas From a Single SAR Amplitude Pair Using the SPIKE Algorithm
摘要： High-resolution three-dimensional (3-D) displacements of mining areas are crucial to assess mining-related geohazards and understand the mining deformation mechanism. In 2018, we proposed a cost-effective and robust method for retrieving mining-induced 3-D displacements from a single SAR amplitude pair (SAP) using offset tracking (OT) procedures. Hereafter, we refer to this method as the 'alternative OT-SAP' (AOT-SAP) method. A key step in the AOT-SAP method is solving the 3-D surface displacements from the AOT-SAP-constructed linear system using routine lower–upper (LU) factorization. However, if the AOT-SAP method is used to retrieve high-resolution 3-D displacements, the dimension of the linear system becomes very large (in the order millions), and a high-end supercomputer is often needed to perform the LU-based solving procedure. This significantly narrows the practical application of the AOT-SAP method, considering the limited availability of supercomputers. In this paper, owing to the banded nature of the AOT-SAP-constructed linear system, we introduce the SPIKE algorithm as an alternative to LU factorization to solve high-resolution mining-induced 3-D displacements. The SPIKE algorithm is a divide-and-conquer direct solver of a large banded system, which can parallelly or sequentially solve a large banded linear system, with a much smaller memory requirement and a shorter time cost than LU factorization. This allows us to retrieve the high-resolution 3-D mining-induced displacements with the AOT-SAP method on either a supercomputer or a standard personal computer. Finally, the accuracy of the retrieved 3-D displacements and the efficiency improvement of the SPIKE algorithm were tested using both simulation analysis and a real dataset.
关键词： large banded system,offset tracking (OT),underground mining,SPIKE algorithm,three-dimensional (3-D) displacements,Interferometric synthetic aperture radar (InSAR)
更新于2025-09-23 15:22:29
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Amplitude Modulation-based Electrical Stimulation for Encoding Multipixel Spatiotemporal Visual Information in Retinal Neural Activities
摘要： Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.
关键词： Degenerated Retina,Electrical Stimulation,Retinal Ganglion Cells,Retinal Implant,Spike Train Decoding,Microelectrode Array
更新于2025-09-23 15:22:29
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Non-parametric Physiological Classification of Retinal Ganglion Cells in the Mouse Retina
摘要： Retinal ganglion cells, the sole output neurons of the retina, exhibit surprising diversity. A recent study reported over 30 distinct types in the mouse retina, indicating that the processing of visual information is highly parallelised in the brain. The advent of high density multi-electrode arrays now enables recording from many hundreds to thousands of neurons from a single retina. Here we describe a method for the automatic classification of large-scale retinal recordings using a simple stimulus paradigm and a spike train distance measure as a clustering metric. We evaluate our approach using synthetic spike trains, and demonstrate that major known cell types are identified in high-density recording sessions from the mouse retina with around 1,000 retinal ganglion cells. A comparison across different retinas reveals substantial variability between preparations, suggesting pooling data across retinas should be approached with caution. As a parameter-free method, our approach is broadly applicable for cellular physiological classification in all sensory modalities.
关键词： classification,retinal ganglion cells,light responses,spike distance,multi-electrode array
更新于2025-09-23 15:22:29
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Molecular Simulations of Laser Spike Annealing of Block-Copolymer Lamellar Thin-Films
摘要： We use molecular dynamic simulations to study the phase behavior of a coarse-grained lamella-forming A-b-B di-block copolymer under thin-film soft confinement for different heating cycle lengths, film thicknesses, and substrate-polymer affinities. This model describes the effect on thin-film morphology with a free surface (air-polymer interface) and a solid substrate. Our simulation results were first validated by showing that they capture changes for the order-disorder transition temperature with annealing conditions consistent with those found in laser spike annealing experiments, when the vertical lamella phase formed on neutral substrates. In addition, simulations with a substrate selective for a particular block revealed the formation of other phases including a mixed vertical-horizontal lamella and a metastable island phase having horizontal but incomplete lamella layers. The nanoscale roughness features of this island phase, and hence its surface wettability, can be tuned with suitable choices of chemistry and annealing conditions.
关键词： thin-film,nanoscale roughness,order-disorder transition,phase behavior,laser spike annealing,molecular dynamic simulations,block copolymer
更新于2025-09-23 15:21:01
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Numerical Implementation of Wavelength-Dependent Photonic Spike Timing Dependent Plasticity Based on VCSOA
摘要： We propose to realize photonic spike timing dependent plasticity (STDP) by using a vertical-cavity semiconductor optical amplifier (VCSOA) subject to dual optical pulse injections. The computational model of the photonic STDP is presented for the first time based on the well-known Fabry–Pérot approach. Through numerical simulations, the dependences of photonic STDP on the bias current of VCSOA and the input powers are analyzed carefully. Besides, the effect of the initial wavelength detuning on the photonic STDP is also explored. It is found that, the current scheme requires much lower bias current and input power to obtain controllable STDP curve when compared with the previously reported photonic STDP circuits; the initial wavelength detuning is an effectively controllable parameter to realize wavelength-dependent photonic STDP. The computational model of the photonic STDP based on a VCSOA is interesting and valuable for numerically simulating of large-scale photonic spiking neural network, and provides a guideline to design low power consumption photonic neuromorphic systems.
关键词： dual optical pulse injections,Vertical-cavity semiconductor optical amplifier,photonic neuromorphic systems,photonic spike timing dependent plasticity,lower power consumption
更新于2025-09-23 15:21:01
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Online Detection and Sorting of Single-Unit Recording Signal for Closed Loop Optogenetics Controlling
摘要： Electrical brain stimulation provides therapeutic benefits for patients with drug-resistant neurological disorders. But it has restricted access to cell-type selectivity. Optogenetics, in contrast, enables precise targeting of a specific cell type which can address the issue with electrical brain stimulation. Optogenetics is a light-based stimulation method, in which the target cells are transfected with light-sensitive ion channels called opsin. This technique can be used for both excitation and inhibition of cells based on light wavelength and opsin properties. To online modulation of neurons need a closed loop controlling. Closed-loop optogenetics system compares the neural signals with a predefined value at every moment and then decides what to do to achieve the desired value by optical stimulation [1]. One of the important brain signal recordings is single-unit recording (SUR) [2] whiles the most of signal processing method is offline. In this paper, an algorithm was proposed to online spike detection and sorting them based on wavelet transform which was programmed by Labview software. The algorithm consists of three main steps such as detecting spikes, extracting the features of every detected spike and assigning similar spikes to one group. The background noise in multi-unit recording has Gaussian distribution and it contains spikes which the mean value of the signal was considered in signal processing. Time of calculating the main value is about 6.04 μs. If the mean value of a dataset changes noticeably from the estimated value, a candidate spike has occurred. Detected spikes are a discrete sample of the real spikes which the waveforms should be interpolated to improve the detection spike [3]. With detecting a spike, its features must be extracted as the input of spike sorting algorithm. Spikes were sorted in different clusters based on their shapes. Wavelet transform compares the input signal with a predefined function known as a wavelet in different scales. In this algorithm was used 20 scales and Mexican hat wavelet to transform the SUR signal [4]. Total time for interpolation and applying wavelet transform takes about 5.3 ms. The final step of the algorithm is sorting the detected spikes using the extracted features based on applying the wavelet transform and compared all wavelet coefficients of a detected spike with the corresponding coefficients of all the clusters. If the wavelet coefficient in the clusters was within 30% of the corresponding coefficient of the detected spike in all scales, spike put in one group. This part of the algorithm takes about 3.1 ms. Schematic diagram of spike sorting and a photo of the front panel of designed software was shown in Fig.1. In conclusion, designed software has a high processing speed and can be used for online and fully automatic spike sorting for studying and controlling the neural network system with closed loop optogenetics technique.
关键词： Wavelet transform,Spike sorting,Optogenetics,Spike detection,Single-unit recording,Labview
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
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Surface functionalization under water using picosecond and femtosecond laser pulses – first observations and novel effects
摘要： Functionalization by changing the topography of workpiece surfaces is interesting for many applications. Lasers – especially ultrashort pulse lasers – are flexible tools for this kind of tasks. Besides deterministic structures they allow for processing surfaces in a way that stochastic structures appear. Ripple and spike structures can be fabricated in air. In liquids, however, there are only a few investigations and many open questions. The idea of this paper is to check how water in contact to the workpiece surface affects femtosecond laser surface processing and what kind of structures appear. Results obtained with a picosecond laser are presented for comparison.
关键词： ultrashort pulse laser,surface functionalization,spike structures,material processing in liquids
更新于2025-09-12 10:27:22
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - A Novel Cognitive Neuromorphic Polarimetric Dynamic Vision System (pDVS) with Enhanced Discrimination and Temporal Contrast
摘要： In this preliminary study, a new cognitive vision architecture of a Polarimetric Dynamic Vision Sensor ( pDVS), is presented. The system consists of a neuromorphic camera coupled to polarization filters; a spinning wheel, namely, a light modulating wheel, operating at different speeds, is placed in front a static object. The detector system performance against different modulating speeds, under unpolarized and polarized conditions, has been tested, data were acquired and then analyzed. The outcome of this study indicates that enhanced temporal contrast resolution can be achieved, while offering unique discrimination capabilities, depending upon the light polarization states.
关键词： high-discrimination-based on light polarization states,target system design,visual information processing,high-temporal contrast,neuromorphic cognitive spike event-based Polarimetric Dynamic Vision Sensor (pDVS)
更新于2025-09-10 09:29:36