| 1. |
- Wang, Deyu, et al.
(författare)
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FPGA-Based HPC for Associative Memory System
- 2024
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Ingår i: 29TH ASIA AND SOUTH PACIFIC DESIGN AUTOMATION CONFERENCE, ASP-DAC 2024. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 52-57
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Konferensbidrag (refereegranskat)abstract
- Associative memory plays a crucial role in the cognitive capabilities of the human brain. The Bayesian Confidence Propagation Neural Network (BCPNN) is a cortex model capable of emulating brain-like cognitive capabilities, particularly associative memory. However, the existing GPU-based approach for BCPNN simulations faces challenges in terms of time overhead and power efficiency. In this paper, we propose a novel FPGA-based high performance computing (HPC) design for the BCPNN-based associative memory system. Our design endeavors to maximize the spatial and timing utilization of FPGA while adhering to the constraints of the available hardware resources. By incorporating optimization techniques including shared parallel computing units, hybrid-precision computing for a hybrid update mechanism, and the globally asynchronous and locally synchronous (GALS) strategy, we achieve a maximum network size of 150x10 and a peak working frequency of 100 MHz for the BCPNN-based associative memory system on the Xilinx Alveo U200 Card. The tradeoff between performance and hardware overhead of the design is explored and evaluated. Compared with the GPU counterpart, the FPGA-based implementation demonstrates significant improvements in both performance and energy efficiency, achieving a maximum latency reduction of 33.25x, and a power reduction of over 6.9x, all while maintaining the same network configuration.
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| 2. |
- Wang, Deyu, et al.
(författare)
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Memristor-Based In-Circuit Computation for Trace-Based STDP
- 2022
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Ingår i: 2022 Ieee International Conference On Artificial Intelligence Circuits And Systems (Aicas 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Recently, memristors have been widely used to implement Spiking Neural Networks (SNNs), which is promising in edge computing scenarios. However, most memristor-based SNN implementations adopt simplified spike-timing-dependent plasticity (STDP) for the online learning process. It is challenging for memristor-based implementations to support the trace-based STDP learning rules that have been widely used in neuromorphic applications. This paper proposed a versatile memristor-based architecture to implement the synaptic-level trace-based STDP learning rules. Especially, the similarity between synaptic trace dynamics and the memristor nonlinearity is explored and exploited to emulate the trace variables of trace-based STDP. As two typical trace-based STDP learning rules, the pairwise STDP and the triplet STDP, are simulated on two typical nonlinear bipolar memristor devices. The simulation results show that the behavior of physical memristor devices can be well estimated (below 6% in terms of the relative root-mean-square error), and the memristor-based in-circuit computation for trace-based STDP learning rules can achieve a high correlation coefficient over 98%.
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| 3. |
- Bao, D., et al.
(författare)
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A wirelessly-powered UWB sensor tag with time-domain sensor interface
- 2014
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Ingår i: Proceedings - IEEE International Symposium on Circuits and Systems. - 9781479934324 ; , s. 2503-2506
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Konferensbidrag (refereegranskat)abstract
- This paper presents a wirelessly-powered sensor tag with a time-domain sensor interface for wireless sensing applications. The tag is remotely powered by RF wave. Instead of traditional approaches employing conventional ADCs for quantization and transmitter for data communication, in this work, a Pulse Position Modulator incorporating simple impulse radio UWB (IR-UWB) transmitter is proposed to convert and transmit the analog sensing information in time domain. The analog signal is compared with an adjustable triangular wave for analog to time conversion in signal-varying environments. Then a UWB transmitter converts the PPM signal to very short pulses and sends it back to the reader. The time interval of UWB pulses represents the original input signal in time domain which can be measured on the reader side by a time-to-digital conversion. This approach not only simplifies the ADC design but also relaxes the number of bits transmitted on the tag side. The sensor tag is designed in 180nm CMOS process. Simulation results demonstrate that the proposed approach reduce transmission power consumption by nearly 3 orders of magnitude over traditional approaches, while consuming only 85 μW for 1.5 MS/s sampling rate.
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| 4. |
- Löwemark, Ludvig, et al.
(författare)
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Glacio-eustatic influence on deep water circulation in the South China Sea over the past 500 kyrs – implications for global biogeochemical cycling
- 2008
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Ingår i: Western Pacific Geophysics Meeting, American Geophysical Union, Cairns, Australia, July/August 2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We provide new evidence for the development of a stable estuarinecirculation characterized by stagnating water bodies, nutrient recycling and increased primary productivity in the South China Seaduring glacial intervals caused by the closure of the shallow andnarrow straits connecting the South China Sea in the south and west. Our main evidence comes from records of Mn concentrations and Mn/Al ratios in two sedimentary cores from the northern and southeastern South China Sea covering the last 500 ky. Concentrations and Mn/Al ratios of the redox sensitive element Mn show clear glacial-interglacial cycles with maxima during interglacial periods and minima during glacial periods. These cycles indicate ventilation cycles of the bottom water connected to the glacial-interglacial changes in sea level. In contrast, total organic carbon (TOC) concentrations display an opposite pattern with pronounced maxima during glacial times, especially in the southern part of the basin. The variations in TOC can be ascribed to two factors. Firstly to variations in primary productivity controlled by variations in theintensity of the winter monsoon. Secondly to the degree of preservation of TOC controlled by variations in ventilation, ultimately controlled by sea level. Variations in TOC consequentlyrepresent a superimposition of sea level influenced preservationcontrol and primarily winter monsoon driven variations in primaryproductivity intensity. The decrease in Mn correspond to times when sea level dropped below 40-50 m. Larger amplitude of the variations in TOC and Mn in the southern part of the basin compared to the northern sites suggest that oxygen depletion and nutrient recycling was stronger in the parts of the basin situated the furthest from the only remaining opening to the open Pacific, the Luzon strait.
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| 5. |
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| 6. |
- Mao, Jia, et al.
(författare)
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A 90nm CMOS UHF/UWB asymmetric transceiver for RFID readers
- 2011
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Ingår i: European Solid-State Circuits Conference. ; , s. 179-182
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents an integrated asymmetric transceiver in 90nm CMOS technology for RFID reader. The proposed reader uses UHF transmitter to power up and inventory the tags. In the reverse link, a non-coherent Ultra-wide Band (UWB) receiver is deployed for data reception with high throughput and ranging capability. The transmitter delivers 160 kb/s ASK modulated data by an integrated modulator and a Digital Controlled Oscillator (DCO) in UHF band with 11% tuning range. The DCO consume 6 mW with 0.12 mm2 area. On the other side, adopting two integration channels, the 3-5 GHz energy detection receiver supports maximum 33 Mb/s data rate both in OOK and PPM modulations. The receiver front-end provides 59 dB voltage gain and 8.5 dB noise figure (NF). Measurement results shows that the receiver achieves an input sensitivity of -79 dBm at 10 Mb/s, with power consumption of 15.5 mW.
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| 7. |
- Sarmiento M., David, et al.
(författare)
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Analog front-end RX design for UWB impulse radio in 90nm CMOS
- 2011
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Ingår i: 2011 IEEE International Symposium of Circuits and Systems, ISCAS 2011. ; , s. 1552-1555
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Konferensbidrag (refereegranskat)abstract
- In this paper a reconfigurable differential Ultra Wideband-Impulse Radio (UWB-IR) energy receiver architecture has been simulated and implemented in UMC 90nm. The signal is amplified, rectified and integrated. By using an integration windowed scheme the SNR requirements are relaxed increasing the sensitivity. The design has been optimized for large bandwidths, low implementation area and configurability. The RX can be adapted to work at different data rates, processing gains, and channel environments. It works between the 3.1-4.8 GHz bands with OOK or PPM modulation with a tunable data rate up to 33Mb/s. In order to relax the ADC sampling time an interleave mode of operation has been implemented. It has a maximum power consumption of 22m W with a power supply of 1V. The complete RX occupies an area of 1.11mm2.
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| 8. |
- Wang, C., et al.
(författare)
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A wearable ECG monitoring device with flexible embedded denoising and compression
- 2016
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Ingår i: European Solid-State Circuits Conference. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 87-90, s. 79-82, s. 87-90
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Konferensbidrag (refereegranskat)abstract
- A wearable electrocardiogram (ECG) monitoring device with a customized SoC is reported. The SoC amplifies the ECG signal from passive electrodes and then digitizes and transforms it into wavelet coefficients. A low-power microcontroller (MCU) and a radio frequency (RF) module in the device resolve and send the wavelet coefficients to a mobile platform. The mobile platform uses machine learning algorithms to improve the performance of signal denoising and data compression by exploiting the characteristics of the sensed data, and consequently reduces power consumption in the wearable device. Measurement results show that the device can resolve ECG data from MIT-BIH arrhythmia database and actual ECG signals from human testers. After processing the ECG data with various noise models, the proposed device can improve the signal to noise ratio (SNR) and mean square error (MSE) by 23.8dB and 88.9%, respectively. When resolving actual ECG signals from testers, the typical compression ratio (CR) is 4.8:1 with 1.56% percentage root mean square difference (PRD). The SoC is fabricated in TSMC 0.18μm technology, and consumes 45μw for different applications.
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| 9. |
- Wang, Peng, et al.
(författare)
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A novel low-power fully-differential current-reuse cascaded CG-CS-LNA for 6-9-GHz UWB receivers
- 2010
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Ingår i: 2010 IEEE International Conference on Electronics, Circuits, and Systems, ICECS 2010. - 9781424481576 ; , s. 1188-1191
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a novel low-power fully-differential ultra-wideband (UWB) low noise amplifier (LNA) for 6-9-GHz UWB receivers in digital 90nm CMOS. The capacitive cross-coupled common-gate (CG) stage is cascaded with a cross-coupled common-source (CS) second stage to perform the wideband input impedance matching, low noise figure (NF), low power, and flat-high-wideband gain which is due to the stagger tuning amplification. The DC power consumption is further reduced by the current-reuse topology. The simulation results achieve the minimum NF of 2.55dB, maximum voltage gain of 24.8dB with 3-dB bandwidth of 6-9-GHz, and IIP3 of 3.57dBm at 9GHz. The return loss is less than -12dB in the desired band because of the CG stage as the input stage. The proposed UWB LNA consumes 2.3mW core DC power at 1V supply voltage.
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| 10. |
- Wang, Peng, et al.
(författare)
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Low Noise Amplifier Architecture Analysis for UWB System
- 2008
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Ingår i: 2008 INTERNATIONAL SYMPOSIUM ON SYSTEM-ON-CHIP, PROCEEDINGS. - NEW YORK : IEEE. ; , s. 53-56
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes the architecture of wideband low noise amplifier (LNA) for multi-band orthogonal frequency division multiplexing modulation (MB-OFDM) ultra-wideband (UWB) system. Noise matching and input impedance matching are compared among different LNA architectures. Power consumption and area for different kinds of LNA architectures are also compared through the figure of merit (FOM).
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