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A Compressive Phase-Locked Loop
(2011)
We develop a new method for tracking narrowband signals acquired through compressive sensing, called the compressive sensing phase-locked loop (CS-PLL). The CS-PLL enables one to track oscillating signals in very large bandwidths using a small number of measurements. Not only does the CS-PLL potentially operate below the Nyquist rate, it can extract ...
Efficient Resource Allocation in Multiflow Wireless Networks
(2011)
We consider the problem of allocating resources in large wireless net- works in which multiple information flows must be accommodated. In particular, we seek a method for selecting schedules, routes, and power allocations for networks with terminals capable of user-cooperation at the signal level. To that end, we adopt a general information-theoretic ...
Nonlinear Signal Models: Geometry, Algorithms, and Analysis
(2013-07-24)
Traditional signal processing systems, based on linear modeling principles, face a stifling pressure to meet present-day demands caused by the deluge of data generated, transmitted and processed across the globe. Fortunately, recent advances have resulted in the emergence of more sophisticated, nonlinear signal models. Such nonlinear models have ...
IO-lite: A copy-free UNIX I/O system
(1997)
Memory copy speed is known to be a significant barrier to high-speed communication. We perform an analysis of the requirements for a copy-free buffer system, develop an implementation-independent applications programming interface (API) based on those requirements, and then implement a system that conforms to the API. In addition, we design and ...
Cache management in scalable network servers
(2000)
For many users, the perceived speed of computing is increasingly dependent on the performance of network server systems, underscoring the need for high performance servers. Cost-effective scalable network servers can be built on clusters of commodity components (PCs and LANs) instead of using expensive multiprocessor systems. However, network servers ...
Golden-Eye: A server-side location-sensing system for wireless LANs
(2004)
Determining the location of a wireless client is a key problem for location-aware systems and for security applications. Many recent studies have used Bayesian methods to determine location from wireless LAN signals, but such methods have the drawback that a model must first be built from training data. The introduction of model error can drastically ...
Statistical characterization of sensors for sensor fusion
(1996)
It is standard practice in advanced telerobotic systems to use a detailed model of the operating environment to plan tasks and drive simulations. How well these systems operate is highly dependent upon the accuracy of this model. As objects are moved by manipulators, inaccuracies in the world model will accumulate, progressively reducing the overall ...
The wavelet transforms and time-scale analysis of signals
(1990)
Orthonormal wavelet bases provide an alternative technique for the analysis of non-stationary signals. Unlike the Gabor representation, the basis functions in the wavelet representation all have the same band width on a logarithmic scale.
This thesis develops a general framework for the time-scale analysis of signals. In this context, the ON wavelets ...
Channel estimation for code division multiple access communication systems
(1994)
We consider the estimation of channel parameters for code division multiple access (CDMA) communication systems operating over channels with either single or multiple propagation paths. We present two approaches for decomposing this multiuser channel estimation problem into a series of single user problems. In the first method, the interfering users ...
Material parameter estimation and imaging with terahertz time-domain spectroscopy
(2002)
Terahertz time-domain spectroscopy (THz-TDS) offers a range of unique imaging modalities due to the broad bandwidth, sub-picosecond duration, and phase-sensitive detection of the THz pulses. Previous research in the THz field primarily focused on improving the optoelectronics and on qualitative investigation of suitable applications. In this thesis, ...