Spin-Based Neuron Model with Domain Wall Magnets as Synapse

We present artificial neural network design using spin devices that achieves ultra low voltage operation, low power consumption, high speed, and high integration density. We employ spin torque switched nano-magnets for modelling neuron and domain wall magnets for compact, programmable synapses. The spin based neuron-synapse units operate locally at ultra low supply voltage of 30mV resulting in low computation power. CMOS based inter-neuron communication is employed to realize network-level functionality. We corroborate circuit operation with physics based models developed for the spin devices. Simulation results for character recognition as a benchmark application shows 95% lower power consumption as compared to 45nm CMOS design

A 24-GHz SiGe Phased-Array Receiver—LO Phase-Shifting Approach

A local-oscillator phase-shifting approach is introduced to implement a fully integrated 24-GHz phased-array receiver using an SiGe technology. Sixteen phases of the local oscillator are generated in one oscillator core, resulting in a raw beam-forming accuracy of 4 bits. These phases are distributed to all eight receiving paths of the array by a symmetric network. The appropriate phase for each path is selected using high-frequency analog multiplexers. The raw beam-steering resolution of the array is better than 10 [degrees] for a forward-looking angle, while the array spatial selectivity, without any amplitude correction, is better than 20 dB. The overall gain of the array is 61 dB, while the array improves the input signal-to-noise ratio by 9 dB

Interconnect-driven floorplanning.

Sham Chiu Wing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 107-113).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivations --- p.1Chapter 1.2 --- Progress on the Problem --- p.2Chapter 1.3 --- Our Contributions --- p.3Chapter 1.4 --- Thesis Organization --- p.5Chapter 2 --- Preliminaries --- p.6Chapter 2.1 --- Introduction --- p.6Chapter 2.1.1 --- The Role of Floorplanning --- p.6Chapter 2.1.2 --- Wirelength Estimation --- p.7Chapter 2.1.3 --- Different Types of Floorplan --- p.8Chapter 2.2 --- Representations of Floorplan --- p.10Chapter 2.2.1 --- Polish Expressions --- p.10Chapter 2.2.2 --- Sequence Pair --- p.11Chapter 2.2.3 --- Bounded-Sliceline Grid (BSG) Structure --- p.13Chapter 2.2.4 --- O-Tree --- p.14Chapter 2.2.5 --- B*-Tree --- p.16Chapter 2.2.6 --- Corner Block List --- p.18Chapter 2.2.7 --- Twin Binary Tree --- p.19Chapter 2.2.8 --- Comparisons between Different Representations --- p.20Chapter 2.3 --- Algorithms of Floorplan Design --- p.20Chapter 2.3.1 --- Constraint Based Floorplanning --- p.21Chapter 2.3.2 --- Integer Programming Based Floorplanning --- p.21Chapter 2.3.3 --- Neural Learning Based Floorplanning --- p.22Chapter 2.3.4 --- Rectangular Dualization --- p.22Chapter 2.3.5 --- Simulated Annealing --- p.23Chapter 2.3.6 --- Genetic Algorithm --- p.23Chapter 2.4 --- Summary --- p.24Chapter 3 --- Literature Review on Interconnect-Driven Floorplanning --- p.25Chapter 3.1 --- Introduction --- p.25Chapter 3.2 --- Simulated Annealing Approach --- p.25Chapter 3.2.1 --- """Pepper - A Timing Driven Early Floorplanner""" --- p.25Chapter 3.2.2 --- """A Timing Driven Block Placer Based on Sequence Pair Model""" --- p.26Chapter 3.2.3 --- """Integrated Floorplanning and Interconnect Planning""" --- p.27Chapter 3.2.4 --- """Interconnect Driven Floorplanning with Fast Global Wiring Planning and Optimization""" --- p.27Chapter 3.3 --- Genetic Algorithm Approach --- p.28Chapter 3.3.1 --- "“Timing Influenced General-cell Genetic Floorplanning""" --- p.28Chapter 3.4 --- Force Directed Approach --- p.29Chapter 3.4.1 --- """Timing Influenced Force Directed Floorplanning""" --- p.29Chapter 3.5 --- Congestion Planning --- p.30Chapter 3.5.1 --- """On the Behavior of Congestion Minimization During Placement""" --- p.30Chapter 3.5.2 --- """Congestion Minimization During Placement""" --- p.31Chapter 3.5.3 --- "“Estimating Routing Congestion Using Probabilistic Anal- ysis""" --- p.31Chapter 3.6 --- Buffer Planning --- p.32Chapter 3.6.1 --- """Buffer Block Planning for Interconnect Driven Floor- planning""" --- p.32Chapter 3.6.2 --- """Routability Driven Repeater Block Planning for Interconnect- centric Floorplanning""" --- p.33Chapter 3.6.3 --- """Provably Good Global Buffering Using an Available Block Plan""" --- p.34Chapter 3.6.4 --- "“Planning Buffer Locations by Network Flows""" --- p.34Chapter 3.6.5 --- """A Practical Methodology for Early Buffer and Wire Re- source Allocation""" --- p.35Chapter 3.7 --- Summary --- p.36Chapter 4 --- Floorplanner with Fixed Buffer Planning [34] --- p.37Chapter 4.1 --- Introduction --- p.37Chapter 4.2 --- Overview of the Floorplanner --- p.38Chapter 4.3 --- Congestion Model --- p.38Chapter 4.3.1 --- Construction of Grid Structure --- p.39Chapter 4.3.2 --- Counting the Number of Routes at a Grid --- p.40Chapter 4.3.3 --- Buffer Location Computation --- p.41Chapter 4.3.4 --- Counting Routes with Blocked Grids --- p.42Chapter 4.3.5 --- Computing the Probability of Net Crossing --- p.43Chapter 4.4 --- Time Complexity --- p.44Chapter 4.5 --- Simulated Annealing --- p.45Chapter 4.6 --- Wirelength Estimation --- p.46Chapter 4.6.1 --- Center-to-center Estimation --- p.47Chapter 4.6.2 --- Corner-to-corner Estimation --- p.47Chapter 4.6.3 --- Intersection-to-intersection Estimation --- p.48Chapter 4.7 --- Multi-pin Nets Handling --- p.49Chapter 4.8 --- Experimental Results --- p.50Chapter 4.9 --- Summary --- p.51Chapter 5 --- Floorplanner with Flexible Buffer Planning [35] --- p.53Chapter 5.1 --- Introduction --- p.53Chapter 5.2 --- Overview of the Floorplanner --- p.54Chapter 5.3 --- Congestion Model --- p.55Chapter 5.3.1 --- Probabilistic Model with Variable Interval Buffer Inser- tion Constraint --- p.57Chapter 5.3.2 --- Time Complexity --- p.61Chapter 5.4 --- Buffer Planning --- p.62Chapter 5.4.1 --- Estimation of Buffer Usage --- p.62Chapter 5.4.2 --- Estimation of Buffer Resources --- p.69Chapter 5.5 --- Two-phases Simulated Annealing --- p.70Chapter 5.6 --- Wirelength Estimation --- p.72Chapter 5.7 --- Multi-pin Nets Handling --- p.73Chapter 5.8 --- Experimental Results --- p.73Chapter 5.9 --- Remarks --- p.76Chapter 5.10 --- Summary --- p.76Chapter 6 --- Global Router --- p.77Chapter 6.1 --- Introduction --- p.77Chapter 6.2 --- Overview of the Global Router --- p.77Chapter 6.3 --- Buffer Insertion Constraint and Congestion Constraint --- p.78Chapter 6.4 --- Multi-pin Nets Handling --- p.79Chapter 6.5 --- Routing Methodology --- p.79Chapter 6.6 --- Implementation --- p.80Chapter 6.7 --- Summary --- p.86Chapter 7 --- Interconnect-Driven Floorplanning by Alternative Packings --- p.87Chapter 7.1 --- Introduction --- p.87Chapter 7.2 --- Overview of the Method --- p.87Chapter 7.3 --- Searching Alternative Packings --- p.89Chapter 7.3.1 --- Rectangular Supermodules in Sequence Pair --- p.89Chapter 7.3.2 --- Finding rearrangable module sets --- p.90Chapter 7.3.3 --- Alternative Sequence Pairs --- p.94Chapter 7.4 --- Implementation --- p.97Chapter 7.4.1 --- Re-calculation of Interconnect Cost --- p.98Chapter 7.4.2 --- Cost Function --- p.101Chapter 7.4.3 --- Time Complexity --- p.101Chapter 7.5 --- Experimental Results --- p.101Chapter 7.6 --- Summary --- p.103Chapter 8 --- Conclusion --- p.105Bibliography --- p.10

emiT: an apparatus to test time reversal invariance in polarized neutron decay

We describe an apparatus used to measure the triple-correlation term (\D \hat{\sigma}_n\cdot p_e\times p_\nu) in the beta-decay of polarized neutrons. The \D-coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction beta-decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the proton detectors, beta detectors and the electronics used in the data collection system are presented. The neutron beam characteristics, the spin-transport magnetic fields, and polarization measurements are also described.Comment: 15 pages, 13 figure

Development of micromachined millimeter-wave modules for next-generation wireless transceiver front-ends

This thesis discusses the design, fabrication, integration and characterization of millimeter wave passive components using polymer-core-conductor surface micromachining technologies. Several antennas, including a W-band broadband micromachined monopole antenna on a lossy glass substrate, and a Ka-band elevated patch antenna, and a V-band micromachined horn antenna, are presented. All antennas have advantages such as a broad operation band and high efficiency. A low-loss broadband coupler and a high-Q cavity for millimeter-wave applications, using surface micromachining technologies is reported using the same technology. Several low-loss all-pole band-pass filters and transmission-zero filters are developed, respectively. Superior simulation and measurement results show that polymer-core-conductor surface micromachining is a powerful technology for the integration of high-performance cavity, coupler and filters. Integration of high performance millimeter-wave transceiver front-end is also presented for the first time. By elevating a cavity-filter-based duplexer and a horn antenna on top of the substrate and using air as the filler, the dielectric loss can be eliminated. A full-duplex transceiver front-end integrated with amplifiers are designed, fabricated, and comprehensively characterized to demonstrate advantages brought by this surface micromachining technology. It is a low loss and substrate-independent solution for millimeter-wave transceiver integration.Ph.D.Committee Chair: John Papapolymerou; Committee Chair: Manos Tentzeris; Committee Member: Gordon Stuber; Committee Member: John Cressler; Committee Member: John Z. Zhang; Committee Member: Joy Laska

Smart Rocks and Wireless Communication System for Real-Time Monitoring and Mitigation of Bridge Scour -- A Proof-of-Concept Study

This study aims to integrate commercial measurement and communication components into a scour monitoring system with magnets or electronics embedded in smart rocks, and evaluate and improve its performance in laboratory and field conditions for the movement of smart rocks. Properly-designed smart rocks were found to be automatically rolled into the very bottom of a scour hole and can give critical information about the maximum scour depth and effectiveness of rip-rap mitigation strategies. Four types of smart rock technologies were investigated in this proof-of-concept phase of study, including passive with embedded magnets, active with magneto-inductive communication, active with controllable magnet rotation, and active with acoustic communication. Their performances were evaluated against three criteria: 1) movement accuracy within 0.5 m, 2) transmission distance between 5 and 30 m, and 3) at least one measurement every 15 minutes. Test results demonstrated that the proposed smart rocks are cost-effective, viable technologies for bridge scour monitoring

ACBAR: The Arcminute Cosmology Bolometer Array Receiver

We describe the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver designed for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich effect in clusters of galaxies. The ACBAR focal plane consists of a 16-pixel, background-limited, 240 mK bolometer array that can be configured to observe simultaneously at 150, 220, 280, and 350 GHz. With 4-5' FWHM Gaussian beam sizes and a 3 degree azimuth chop, ACBAR is sensitive to a wide range of angular scales. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001. We describe the design of the instrument and its performance during the 2001 and 2002 observing seasons.Comment: 59 pages, 16 figures -- updated to reflect version published in ApJ