Digital Commons Network^™

A Cmos Spiking Neuron For Brain-Inspired Neural Networks With Resistive Synapses And In-Situ Learning, Xinyu Wu, Vishal Saxena, Kehan Zhu, Sakkarapani Balagopal

Electrical and Computer Engineering Faculty Publications and Presentations

Nano-scale resistive memories are expected to fuel dense integration of electronic synapses for large-scale neuromorphic system. To realize such a brain-inspired computing chip, a compact CMOS spiking neuron that performs in-situ learning and computing while driving a large number of resistive synapses is desired. This work presents a novel leaky integrate-and-fire neuron design which implements the dual-mode operation of current integration and synaptic drive, with a single opamp and enables in-situ learning with crossbar resistive synapses. The proposed design was implemented in a 0.18μm CMOS 􀀃technology. Measurements show neuron’s ability to drive a thousand resistive synapses, and demonstrate an in-situ …

Spectrum Sensing Of Ofdm Signals In The Presence Of Carrier Frequency Offset, Weiyang Xu, Wei Xiang, Maged Elkashlan, Hani Mehrpouyan

Electrical and Computer Engineering Faculty Publications and Presentations

This paper addresses the important issue of detecting orthogonal frequency-division multiplexing (OFDM) signals in the presence of carrier frequency offset (CFO). The proposed algorithm utilizes the characteristics of the covariance matrix of the discrete Fourier transform of the input signal to the detector to determine the presence of the primary user’s signal. This algorithm can be exploited to differentiate OFDM signals from the noise through the proposal of a new decision metric, which measures the off-diagonal elements of the input signal’s covariance matrix. The decision threshold subject to a given probability of false alarm is derived, while performance analysis is …

Evolution Of A First-Year Engineering Course, Noah Salzman, Janet Callahan, Gary Leroy Hunt, Carol Sevier, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

The first-year engineering course at Boise State University has evolved significantly over the past decade as a result of continuous improvement with a particular focus on student retention. The course was originally created in 1999-2001 as an “Introduction to Engineering” course in order to recruit students to one of the fields of engineering, by introducing those fields of engineering as topics across the semester. Over the first ten years, the course continued that introductory-to-field focus while also introducing a significant design element solving openended engineering problems. As a result of a five-year grant aimed toward improving first-year retention, the first-year …

Homogeneous Spiking Neuromorphic System For Real-World Pattern Recognition, Xinyu Wu, Vishal Saxena, Kehan Zhu

Electrical and Computer Engineering Faculty Publications and Presentations

A neuromorphic chip that combines CMOS analog spiking neurons and memristive synapses offers a promising solution to brain-inspired computing, as it can provide massive neural network parallelism and density. Previous hybrid analog CMOS-memristor approaches required extensive CMOS circuitry for training, and thus eliminated most of the density advantages gained by the adoption of memristor synapses. Further, they used different waveforms for pre and post-synaptic spikes that added undesirable circuit overhead. Here we describe a hardware architecture that can feature a large number of memristor synapses to learn real-world patterns. We present a versatile CMOS neuron that combines integrate-and-fire behavior, drives …

Phase-Control Of A Rising Sun Magnetron Using A Modulated, Addressable, Current Source, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous

Electrical and Computer Engineering Faculty Publications and Presentations

It has been proposed that the use of gated field emitters with a faceted cathode in place of the conventional thermionic cathode could be used to control the current injection in a magnetron, both temporally and spatially. In this work, this concept is studied using the particle-in-cell code VORPAL. The magnetron studied is a ten-cavity, rising sun magnetron, which can be modeled easily using a 2D simulation. The magnetron has a ten-sided faceted cathode. The electrons are injected from three emitter elements on each of the ten facets. Each emitter is turned ON and OFF in sequence at the oscillating …

Channel Estimation And Optimal Training Design For Correlated Mimo Two-Way Relay Systems In Colored Environment, Rui Wang, Meixia Tao, Hani Mehrpouyan, Yingbo Hua

Electrical and Computer Engineering Faculty Publications and Presentations

In this paper, while considering the impact of antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay (TWR) systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcasting (BC) phase. By considering the Kronecker-structured channel model, we derive the optimal linear minimum mean-square-error (LMMSE) channel estimators. The corresponding training designs for the MAC and BC phases are then formulated and solved to improve channel estimation accuracy. For the general scenario of training sequence …

Thermodynamics And Kinetics Of Dna Nanotube Polymerization From Single-Filament Measurements, Rizal F. Hariadi, Bernard Yurke, Erik Winfree

Electrical and Computer Engineering Faculty Publications and Presentations

DNA nanotubes provide a programmable architecture for molecular self-assembly and can serve as model systems for one-dimensional biomolecular assemblies. While a variety of DNA nanotubes have been synthesized and employed as models for natural biopolymers, an extensive investigation of DNA nanotube kinetics and thermodynamics has been lacking. Using total internal reflection microscopy, DNA nanotube polymerization was monitored in real time at the single filament level over a wide range of free monomer concentrations and temperatures. The measured polymerization rates were subjected to a global nonlinear fit based on polymerization theory in order to simultaneously extract kinetic and thermodynamic parameters. For …

Design Considerations For Traveling-Wave Modulator-Based Cmos Photonic Transmitters, Kehan Zhu, Vishal Saxena, Xinyu Wu, Wan Kuang

Electrical and Computer Engineering Faculty Publications and Presentations

Systematic design and simulation methodology for hybrid optical transmitters that combine CMOS circuits in a 130 nm process, and a traveling-wave Mach-Zehnder modulator (TWMZM) in 130 nm SOI CMOS process, is presented. A compact Verilog-A model for the TWMZM is adopted for the electrooptical simulation. A bond wire model using a high-frequency solver is included for accurate package simulation. Transmitter post-layout simulation result exhibits 5.48 dB extinction ratio, 9.6 ps peak-to-peak jitter, and the best power efficiency of 5.81 pJ/bit when operating up to 12.5 Gb/s non-return-to-zero data. A pulse amplitude modulation 4-level transmitter with detailed linearity design procedure is …

Measuring The Effects Of Pre-College Engineering Experiences, Year 2, Noah Salzman, Matthew W. Ohland, Monica E. Cardella

Electrical and Computer Engineering Faculty Publications and Presentations

The implementation of co-curricular and extracurricular pre-college engineering programs has expanded dramatically in recent years. Many states now include engineering as part of their education standards for both students and teachers, reflecting the increasing acceptance of engineering at the K-12 level and its potential value to students. In addition to promoting outcomes that benefit all students regardless of career aspirations such as increased math and science achievement and greater technological literacy, K-12 engineering programs have been identified as a means of recruiting and retaining potential students in engineering.

The growth of pre-college engineering programs means that increasing numbers of incoming …

Effects Of Clustering Algorithms On Typographic Reconstruction, Elisa H. Barney Smith, Bart Lamiroy

Electrical and Computer Engineering Faculty Publications and Presentations

Type designers and historians studying the typefaces and fonts used in historical documents can usually only rely on available printed material. The initial wooden or metal cast fonts have mostly disappeared. In this paper we address the creation of character templates from printed documents. Images of characters scanned from Renaissance era documents are segmented, then clustered. A template is created from each obtained cluster of similar appearance characters. In order for subsequent typeface analysis tools to operate, the template should reduce the noise present in the individual instances by using information from the set of samples, but the samples must …

Design Analysis Of A 12.5 Ghz Pll In 130 Nm Sige Bicmos Process, Kehan Zhu, Vishal Saxena, Xinyu Wu, Sakkarapani Balagopal

Electrical and Computer Engineering Faculty Publications and Presentations

A systematic design method is applied to study and analyze the loop stability and phase noise of a type-II 3^rd-order charge pump PLL. The designed PLL outputs at 12.5 GHz, which is intended to provide a clock for a silicon photonic transmitter prototype. The charge pump current and loop filter resistor are made tunable to cover process and temperature variations. The PLL is designed in a 130 nm SiGe BiCMOS process. The rms jitter of the studied PLL output is about 5 ps with a 97.7 MHz reference clock with 4.9 ps rms jitter from a 0.05 to …

Template Generation From Postmarks Using Cascaded Unsupervised Learning, Elisa H. Barney Smith, Gernot Fink

Electrical and Computer Engineering Faculty Publications and Presentations

Information in historical datasets comes in many forms. We are working with a set of World War I era postcards that contain hand written text, some preprinted text, postage stamps and postmark/cancellation stamps. The postmarks are of considerable interest to collectors looking for images of samples they had not previously seen. The postmarks also provide information on the originating location of the card that complements the information in the address block.

The postmarks vary considerably with towns and dates, but also styles. The styles can be grouped into categories. A method for automatically extracting templates for each category of these …

A New Equivalent Circuit Of A Salient-Pole Synchronous Machine And Its Phasor Interpretation, Said Ahmed-Zaid, Danyal Mohammadi, Ahmed M.A. Oteafy

Electrical and Computer Engineering Faculty Publications and Presentations

This paper examines a shortcoming of the classical phasor diagram of a salient-pole synchronous machine based on the well-established two-reaction theory. Unlike in the phasor diagram of a smooth-air-gap machine, it is not possible to readily identify the internally-developed electromagnetic power of a salient-pole synchronous machine from this phasor diagram. By defining new machine reactances, a single equivalent circuit of a salient-pole synchronous machine is proposed together with a phasor diagram where the internally-developed electromagnetic power is made apparent. The revised two-reaction theory is illustrated using the mathematical model of a two-phase salient-pole synchronous machine whose equations are manipulated using …

Dynamics Of Silver Photo-Diffusion Into Ge-Chalcogenide Films: Time-Resolved Neutron Reflectometry, M. Ailavajhala, M. R. Latif, K. Wolf, M. Mitkova, M. W.A. Skoda

Electrical and Computer Engineering Faculty Publications and Presentations

Silver diffuses into an amorphous (a-) chalcogenide layer while visible light illuminates Ag/a-chalcogenide films and neutron reflectometry is a suitable technique probing time evolution of the depth profiles without damaging the sample by the probe beam itself. In this paper, we report the results of time-resolved neutron reflectivity measurements of a-Ge₄₀Se₆₀/Ag/ Si films taken while the films are exposed to visible light. From the measurements, we found enormous changes in the neutron reflectivity profile, including a loss of total reflection region, with continuous illumination even after forming one homogeneous layer, which occurred about 50 min after …

A Cmos Spiking Neuron For Dense Memristor-Synapse Connectivity For Brain-Inspired Computing, Xinyu Wu, Vishal Saxena, Kehan Zhu

Electrical and Computer Engineering Faculty Publications and Presentations

Neuromorphic systems that densely integrate CMOS spiking neurons and nano-scale memristor synapses open a new avenue of brain-inspired computing. Existing silicon neurons have molded neural biophysical dynamics but are incompatible with memristor synapses, or used extra training circuitry thus eliminating much of the density advantages gained by using memristors, or were energy inefficient. Here we describe a novel CMOS spiking leaky integrate-and-fire neuron circuit. Building on a reconfigurable architecture with a single opamp, the described neuron accommodates a large number of memristor synapses, and enables online spike timing dependent plasticity (STDP) learning with optimized power consumption. Simulation results of an …

A Comprehensive Design Approach For A Mzm Based Pam-4 Silicon Photonic Transmitter, Kehan Zhu, Vishal Saxena, Xinyu Wu

Electrical and Computer Engineering Faculty Publications and Presentations

A 4-level pulse amplitude modulation (PAM-4) silicon photonic transmitter targeting operation at 25 Gb/s is designed using an electrical-photonic co-design methodology. The prototype consists of an electrical circuit and a photonics circuit, which were designed in 130 nm IBM SiGe BiCMOS process and 130nm IME SOI CMOS process, respectively. Then the two parts will be interfaced via side-by-side wire bonding. The electrical die mainly includes a 12.5 GHz PLL, a full-rate 4- channel uncorrelated 2⁷ − 1 pseudo-random binary sequence (PRBS) generator and CML drivers. The photonics die is a 2-segment Mach-Zehnder modulator (MZM) silicon photonics device with thermal …