Now showing items 1252-1271 of 1854

    • Optimal wavelets for signal decomposition and the existence of scale limited signals 

      Odegard, Jan E.; Gopinath, Ramesh A.; Burrus, C. Sidney (1992-01-15)
      Wavelet methods give a flexible alternative to Fourier methods in non-stationary signal analysis. The concept of <i>band-limitedness</i> plays a fundamental role in Fourier analysis. Since wavelet theory replaces ...
    • Optimally Weighted Highpass Filters using Multiscale Analysis 

      Nowak, Robert David; Baraniuk, Richard G. (1996-04-01)
      An obvious approach to image enhancement is to sharpen bright regions of an image more than darker regions. One very simple method to accomplish this is to weight the amount of highpass filtering proportional to the local ...
    • Optimization of novel developments in Positron Emission Tomography (PET) imaging 

      Chang, Tingting (2012)
      Positron Emission Tomography (PET) is a widely used imaging modality for diagnosing patients with cancer. Recently, there have been three novel developments in PET imaging aiming to increase PET image quality and quantification. ...
    • Optimization Techniques for Feature Extraction in Automatic Pattern Recognition 

      de Figueiredo, Rui J.P. (1979-10-20)
      This report summarizes the work performed under the AFOSR grant 75-2777 over the almost five year period during which the grant was in effect.
    • Optimization Techniques for Minimizing Energy Consumption in Approximate Circuits 

      Muntimadugu, Kirthi Krishna (2011)
      This work presents different global and local optimization techniques for designing "approximate" circuits which decrease energy consumption, one of the most important criteria in present day circuit design. The concept ...
    • Optimized Message Passing Schedules for LDPC Decoding 

      Radosavljevic, Predrag; de Baynast, Alexandre; Cavallaro, Joseph R. (2005-11-01)
      The major drawback of the LDPC codes versus the turbo-codes is their comparative low convergence speed: 25-30 iterations vs. 8-10 iterations for turbo-codes. Recently, Hocevar showed by simulations that the convergence ...
    • Optimized Message Passing Schedules for LDPC Decoding 

      Radosavljevic, Predrag; de Baynast, Alexandre; Cavallaro, Joseph R. (2005-11-01)
      The major drawback of the LDPC codes versus the turbo-codes is their comparative low convergence speed: 25-30 iterations vs. 8-10 iterations for turbo-codes. Recently, Hocevar showed by simulations that the convergence ...
    • Optimizing binary decision systems by manipulating transmission intervals 

      Lexa, Michael; Johnson, Don (2003-07-20)
      We study the optimization of a binary decision system where quantized (soft) decisions are transmitted across an additive white Gaussian noise channel. We adjust the bit transmission intervals to maximize the Chernoff ...
    • Optimizing Physical Layer Data Transmission for Minimal Signal Distortion 

      Johnson, Don; Rodriguez-Diaz, Hiram (2003-04-20)
      When transmitting a sampled signal digitally, data and error correction bits must be transmitted at least as fast as the sampling rate. Typically, each bit is allocated the same transmission time interval, which means the ...
    • Optimum growth window for InAs/GaInSb superlattice materials tailored for very long wavelength infrared detection 

      Haugan, Heather J.; Brown, Gail J.; Mahalingam, Krishnamurthy; Grazulis, Larry; Noe, Gary T.; Ogden, Nathan E.; Kono, Junichiro (2014)
      The authors report growth studies to develop an InAs/GaInSb superlattice (SL) material for very long wavelength infrared detection. They select a SL structure of 47.0 Å InAs/21.5 Å Ga0.75In0.25Sb that is designed for the ...
    • Optimum Quadratic Detection and Estimation Using Generalized Joint Signal Representations 

      Sayeed, Akbar M.; Jones, Douglas L. (1996-12-01)
      Time-frequency analysis has recently undergone significant advances in two main directions: statistically optimized methods that extend the scope of time-frequency-based techniques from merely exploratory data analysis to ...
    • Optoelectronic and Ultraviolet Plasmonics 

      Knight, Mark William (2014-04-07)
      Metallodielectric nanostructures are enabling a revolution in optics. For centuries optical techniques were constrained by the diffraction limit, which prevents the control over light at the nanoscale (~200 nm or less). ...
    • Origins and solutions of proportional unfairness in IEEE 802.11 multi-hop wireless networks 

      Shi, Jingpu (2008)
      Proportional unfairness exists in multi-hop wireless networks where IEEE 802.11 is employed as the medium access control protocol. Some flows may receive very high throughput while some others may receive very low or even ...
    • Origins of the Equivalent Circuit Concept 

      Johnson, Don (2003-04-20)
      The equivalent circuit concept derives from the Superposition Principle and Ohm's Law. Two forms of the equivalent circuit, the Thevenin equivalent and the Norton equivalent, distill any linear circuit into a source and ...
    • Orthogonal Hilbert Transform Filter Banks and Wavelets 

      van Spaendonck, Rutger; Blu, Thierry; Baraniuk, Richard G.; Vetterli, Martin (2003-04-01)
      Complex wavelet transforms offer the opportunity to perform directional and coherent processing based on the local magnitude and phase of signals and images. Although denoising, segmentation, and image enhancement are ...
    • Outage behaviour with delay and CSIT 

      Rajan, Dinesh; Sabharwal, Ashutosh; Aazhang, Behnaam (2004-06-01)
      In this paper, we demonstrate that the packet outage probability for fading channels can be significantly reduced by exploiting queuing delay and transmitter channel information. Queuing delay gain is conceptually similar ...
    • Outage Minimization and Optimal Power Control for the Fading Relay Channel 

      Ahmed, Nasir; Khojastepour, Mohammad; Aazhang, Behnaam (2004-05-01)
      In this work, we show that in the wireless relay network, a tremendous savings in energy can be achieved by having side information at the transmitters and by employing power control. We present efficient protocols and the ...
    • Outage Minimization with Limited Feedback for the Fading Relay Channel 

      Ahmed, Nasir; Khojastepour, Mohammad; Sabharwal, Ashutosh; Aazhang, Behnaam (2006)
      In this work, we consider practical methods to approach the theoretical performance limits in the fading relay channel under different assumptions of transmitter channel knowledge. Specifically, we consider two degrees of ...
    • Overtone resonance enhanced single-tube on-beam quartz enhanced photoacoustic spectrophone 

      Zheng, Huadan; Dong, Lei; Sampaolo, Angelo; Patimisco, Pietro; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Xiao, Liantuan; Spagnolo, Vincenzo; Jia, Suotang; Tittel, Frank K. (2016)
      A single-tube on-beam quartz enhanced photoacoustic spectroscopy (SO-QEPAS) spectrophone, which employs a custom-made quartz tuning fork (QTF) having a prong spacing of 700 μm and operating at the 1st overtone flexural ...
    • An Overview of the AT&T Spoken Document Retrieval System 

      Choi, John; Hindle, Don; Hirschberg, Julia; Magrin-Chagnolleau, Ivan; Nakatani, Christine; Pereira, Fernando; Singhal, Amit; Whittaker, Steve (1998-01-15)
      We present an overview of a spoken document retrieval system developed at AT&T Labs-Research for the HUB4 Broadcast News corpus. This overview includes a description of the intonational phrase boundary detection, ...