A coherent optical processor for displaying a signal's ambiguity function is described. The required time delay is realized by 45 degrees rotations of two identical input transparencies and the Doppler shift by a 1-D Fourier transformation. The entire ambiguity function is displayed in the output (Doppler shift-time delay) plane. Examples of the optically computed ambiguity function for single ...

In a previous study, we isolated human amniotic fluid (AF)-derived mesenchymal stem cells (AF-MSCs) and utilized normoxic conditioned medium (AF-MSC-norCM) which has been shown to accelerate cutaneous wound healing. Because hypoxia enhances the wound healing function of mesenchymal stem cell-conditioned medium (MSC-CM), it is interesting to explore the mechanism responsible for the enhancement ...

This paper presents an implemented, computationally inexpensive technique for disambiguating categories (parts of speech) by exploiting constraints on possible category combinations. Early resolutions of category ambiguities provide a great deal of leverage, simplifying later resolutions of other types of lexical ambiguity. Prioritized pattern action rules (CONDS) are specified for each known c...

A simple algorithm based on discrete chirp Fourier transform (DCFT) is used for the chirp signal parameters estimation in impulse noise environments. A modification of the DCFT is introduced in order to produce accurate estimates in this case. This modification, called the robust DCFT, produces highly accurate results in impulse noise environments, while for the Gaussian noise it is only slight...

In this work we propose a novel ap roach for demodulating Continuous Phase Modulation CPM) signals based Q on the modeling of the instantaneous phase as a piecewise polynomial-phase function. The polynomial modeling can be a good approximation for currently used modulations or it can be-exact if the shaping pulse is chosen to be a oiecewise polvnomial function. The crucial step in the demodulat...

We propose an acoustic feature for speech recognition based on the combination of MFCC and fractional Fourier transform (FrFT). Since the transform order is critical for the performance of FrFT, we use the ambiguity function to adaptively determine the optimal orders of FrFT for each frame. The performance of the proposed feature is compared with traditional MFCCs on recognizing speech of isola...

Nonstationary signals appear often in real-life applications and many of them can be modeled as polynomial phase signals (PPS). High-order ambiguity function (HAF) was rst introduced to estimate the parameters of a single component PPS. But due to its high nonlinearity, HAF has not been widely used for multi-component PPS which appear for example, in Doppler radar applications when multiple tar...

Economists studying choice with partial knowledge typically assume that the decision maker places a subjective distribution on unknown quantities and maximizes expected utility. Someone lacking a subjective distribution faces a problem of choice under ambiguity. This article reviews recent research on policy choice under ambiguity, when the task is to choose treatments for a population. Ambigui...

PURPOSE. To study the relationship between macular cone structure, fundus autofluorescence (AF), and visual function in patients with Stargardt disease (STGD). METHODS. High-resolution images of the macula were obtained with adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography in 12 patients with STGD and 27 age-matched healthy subjects. Measure...

BACKGROUND To investigate the outcome of patients in atrial fibrillation (AF) following mitral valve repair, clinical and echocardiographic follow-up was undertaken in 400 consecutive patients who underwent mitral valvuloplasty from 1987 to 1999. METHODS AND RESULTS The main indications for surgery were degenerative (81.4%), endocarditis (7.1%), rheumatic (6.6%), ischemic (4.6%), and traumati...