Digital Commons Network^™

Hardware Architectures And Implementations For Associative Memories : The Building Blocks Of Hierarchically Distributed Memories, Changjian Gao

Dissertations and Theses

During the past several decades, the semiconductor industry has grown into a global industry with revenues around $300 billion. Intel no longer relies on only transistor scaling for higher CPU performance, but instead, focuses more on multiple cores on a single die. It has been projected that in 2016 most CMOS circuits will be manufactured with 22 nm process. The CMOS circuits will have a large number of defects. Especially when the transistor goes below sub-micron, the original deterministic circuits will start having probabilistic characteristics. Hence, it would be challenging to map traditional computational models onto probabilistic circuits, suggesting a …

Cmol/Cmos Hardware Architectures And Performance/Price For Bayesian Memory - The Building Block Of Intelligent Systems, Mazad Shaheriar Zaveri

Dissertations and Theses

The semiconductor/computer industry has been following Moore's law for several decades and has reaped the benefits in speed and density of the resultant scaling. Transistor density has reached almost one billion per chip, and transistor delays are in picoseconds. However, scaling has slowed down, and the semiconductor industry is now facing several challenges. Hybrid CMOS/nano technologies, such as CMOL, are considered as an interim solution to some of the challenges. Another potential architectural solution includes specialized architectures for applications/models in the intelligent computing domain, one aspect of which includes abstract computational models inspired from the neuro/cognitive sciences.

Consequently in this …

Methodology For Developing A Functional Multiscale Architecture Model System Towards Future Integrated Circuits, Yamini Yadov

Dissertations and Theses

Detection of the biochemical species in the environmental pollution, industrial emission monitoring, medical diagnosis, public security, agriculture and a variety of industries has resulted in the emerging need for a generation of high density nanostructured sensor arrays. The fundamental two terminal and three terminal device components because of their potential for specificity eventually have to be integrated into miniaturized and portable nanoarray sensors. One of the key components in these nanosensors is the development of building functional building blocks that improve device performance capabilities. This research is focused on methodology for developing fundamental, functional, multiscale architecture model system for generating …

Lidar System Model For Use With Path Obscurants And Experimental Validation, J. W. Giles, I. N. Bankman, R. M. Sova, T. R. Morgan, Donald D. Duncan, J. A. Millard, W. J. Green, F. J. Marcotte

Electrical and Computer Engineering Faculty Publications and Presentations

When lidar pulses travel through a short path that includes a relatively high concentration of aerosols, scattering phenomena can alter the power and temporal properties of the pulses significantly, causing undesirable effects in the received pulse. In many applications the design of the lidar transmitter and receiver must consider adverse environmental aerosol conditions to ensure the desired performance. We present an analytical model of lidar system operation when the optical path includes aerosols for use in support of instrument design, simulations, and system evaluation. The model considers an optical path terminated with a solid object, although it can also be …

Modeling Broadband Ocean Acoustic Transmissions With Time-Varying Sea Surfaces, Martin Siderius, Michael B. Porter

Electrical and Computer Engineering Faculty Publications and Presentations

Solutions to ocean acoustic scattering problems are often formulated in the frequency domain, which implies that the surface is "frozen" in time. This may be reasonable for short duration signals but breaks down if the surface changes appreciably over the transmission time. Frequency domain solutions are also impractical for source-receiver ranges and frequency bands typical for applications such as acoustic communications (e.g. hundreds to thousands of meters, 1-50 kHz band). In addition, a driving factor in the performance of certain acoustic systems is the Doppler spread, which is often introduced from sea-surface movement. The time-varying nature of the sea surface …

Financial Engineering For Energy System Capital Budgeting, Chin-Chuen Teoh

Dissertations and Theses

The United State energy industry is experiencing a major paradigm shift. This conventional vertically integrated energy industry is gradually transformed to a competitive market environment—a deregulated energy market. The market and regulatory frameworks are expected to continue to evolve in the future. Market participants are emphasizing more on profit maximization as returns on investment are no longer guaranteed. Therefore, risk management and capital budgeting play critical roles in energy system planning. Planning always involves uncertainties. When there are uncertainties, there are risks involve. This dissertation concentrates on the application of Real Options Analysis, ROA, especially lattice method, to energy system …

Advanced Algorithms For Vlsi: Statistical Circuit Optimization And Cyclic Circuit Analysis, Osama Neiroukh

Dissertations and Theses

This work focuses on two emerging fields in VLSI. The first is use of statistical formulations to tackle one of the classical problems in VLSI design and analysis domains, namely gate sizing. The second is on analysis of nontraditional digital systems in the form of cyclic combinational circuits.

In the first part, a new approach for enhancing the process-variation tolerance of digital circuits is described. We extend recent advances in statistical timing analysis into an optimization framework. Our objective is to reduce the performance variance of a technology-mapped circuit where delays across elements are represented by random variables which capture …

Measurement Of Oxygen Saturation In The Retina With A Spectroscopic Sensitive Multi Aperture Camera, Jessica C. Ramella-Roman, Scott A. Mathews, Haripriya Kandimalla, Afshin Nabili, Donald D. Duncan, Salvatore A. D'Anna, Syed M. Shah, Quan D. Nguyen

Electrical and Computer Engineering Faculty Publications and Presentations

We introduce a new multi aperture system capable of capturing six identical images of the human fundus at six different spectral bands. The system is based on a lenslet array architecture and is well suited for spectroscopy application. The multi-aperture system was interfaced with a fundus camera to acquire spectroscopic sensitive images of the retina vessel and ultimately to calculate oxygen saturation in the retina in vivo. In vitro testing showed that the system is able to accurately reconstruct curves of partially oxygenated hemoglobin. In vivo testing on healthy volunteers was conducted and yielded results of oxygen saturation similar to …

Design Of Radio-Frequency Filters And Oscillators In Deep-Submicron Cmos Technology, Haiqiao Xiao

Dissertations and Theses

Radio-frequency filters and oscillators are widely used in wireless communication and high-speed digital systems, and they are mostly built on passive integrated inductors, which occupy a relative large silicon area. This research attempted to implement filters and oscillators operating at 1-5 GHz using transistors only, to reduce the circuits’ area. The filters and oscillators are designed using active inductors, based on the gyrator principle; they are fabricated in standard digital CMOS technology to be compatible with logic circuits and further lower the cost. To obtain the highest operating frequency, only parasitic capacitors were used.

Two new active-inductor circuits are derived …

Bottom Profiling By Correlating Beam-Steered Noise Sequences, Chris H. Harrison, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

It has already been established that by cross-correlating ambient noisetime series received on the upward and downward steered beams of a drifting vertical array one can obtain a subbottom layer profile. Strictly, the time differential of the cross correlation is the impulse response of the seabed. Here it is shown theoretically and by simulation that completely uncorrelated surfacenoise results in a layer profile with predictable amplitudes proportional to those of an equivalent echo sounder at the same depth as the array. The phenomenon is simulated by representing the sound sources as multiple random time sequences emitted from random locations in …

Monte Carlo Modeling Of Spatial Coherence: Free-Space Diffraction, Donald D. Duncan, David G. Fischer, Scott A. Prahl

Electrical and Computer Engineering Faculty Publications and Presentations

We present a Monte Carlo method for propagating partially coherent fields through complex deterministic optical systems. A Gaussian copula is used to synthesize a random source with an arbitrary spatial coherence function. Physical optics and Monte Carlo predictions of the first- and second-order statistics of the field are shown for coherent and partially coherent sources for free-space propagation, imaging using a binary Fresnel zone plate, and propagation through a limiting aperture. Excellent agreement between the physical optics and Monte Carlo predictions is demonstrated in all cases. Convergence criteria are presented for judging the quality of the Monte Carlo predictions.

Can Laser Speckle Flowmetry Be Made A Quantitative Tool?, Donald D. Duncan, Sean J. Kirkpatrick

Electrical and Computer Engineering Faculty Publications and Presentations

The ultimate objective of laser speckle flowmetry (and a host of specific implementations such as laser speckle contrast analysis, LASCA or LSCA; laser speckle spatial contrast analysis, LSSCA; laser speckle temporal contrast analysis, LSTCA; etc.) is to infer flow velocity from the observed speckle contrast. Despite numerous demonstrations over the past 25 years of such a qualitative relationship, no convincing quantitative relationship has been proven. One reason is a persistent mathematical error that has been propagated by a host of workers; another is a misconception about the proper autocorrelation function for ordered flow. Still another hindrance has been uncertainty in …

The Copula: A Tool For Simulating Speckle Dynamics, Donald D. Duncan, Sean J. Kirkpatrick

Electrical and Computer Engineering Faculty Publications and Presentations

Use of a copula for generating a sequence of correlated speckle patterns is introduced. The chief characteristic of this algorithm is that it generates a continuous speckle sequence with a specified evolution of the correlation and does so with just two arrays of random numbers. Thus, physically realistic temporally varying speckle patterns with proper first- and second-order statistics are easily realized. We illustrate use of the algorithm for generating sequences with prescribed Gaussian, exponential, and equal-interval correlations and demonstrate how correlation times can be specified independently. This approach to generating sequences of random realizations with prescribed correlations should prove useful …

Statistics Of Local Speckle Contrast, Donald D. Duncan, Sean J. Kirkpatrick, Ruikang K. Wang

Electrical and Computer Engineering Faculty Publications and Presentations

In describing the first-order properties of laser speckle under polarized illumination conditions, it is almost an article of faith that the contrast is unity. In many processing schemes, however, the contrast defined as the quotient of the standard deviation and the mean is calculated over a localized spatial region. In such cases, this local contrast displays a distribution of values that can depart substantially from unity. Properties of this distribution depend on details of the data acquisition and on the size of the local neighborhood over which the contrast is calculated. We demonstrate that this local contrast can be characterized …