Digital Signal Processing

Fast varying channel estimation in downlink LTE systems

by Youssef El Hajj Shehadeh

Optimal feature selection for the assessment of vocal fold disorders

by Hossein Khadivi Heris

Fuzzy logic based classification and assessment of pathological voice signals

by Hossein Khadivi Heris

Mixing for Parlak and Bowing for a Büyük Ses: The Aesthetics of Arranged Traditional Music in Turkey.

by Eliot Bates

published in Ethnomusicology 54(1), 2010

Glitches, bugs, and hisses: the degeneration of musical recordings and the contemporary musical work

by Eliot Bates

in Bad Music: Music you Love to Hate, edited by Chris Washburne and Maiken Derno, 2004

Improving the sensitivity of high-frequency subharmonic imaging with coded excitation: A feasibility study

by Himanshu Shekhar

Himanshu Shekhar and Marvin M. Doyley
Medical Physics / Volume 39 / Issue 4 / ULTRASOUND PHYSICS

Purpose: Subharmonic intravascular ultrasound imaging (S-IVUS) could visualize the adventitial vasa vasorum, but the... more Purpose: Subharmonic intravascular ultrasound imaging (S-IVUS) could visualize the adventitial vasa vasorum, but the high pressure threshold required to incite subharmonic behavior in an ultrasound contrast agent will compromise sensitivity—a trait that has hampered the clinical use of S-IVUS. The purpose of this study was to assess the feasibility of using coded-chirp excitations to improve the sensitivity and axial resolution of S-IVUS.
Methods: The subharmonic response of Targestar-pTM, a commercial microbubble ultrasound contrast agent (UCA), to coded-chirp (5%–20% fractional bandwidth) pulses and narrowband sine-burst (4% fractional bandwidth) pulses was assessed, first using computer simulations and then experimentally. Rectangular windowed excitation pulses with pulse durations ranging from 0.25 to 3 μs were used in all studies. All experimental studies were performed with a pair of transducers (20 MHz/10 MHz), both with diameter of 6.35 mm and focal length of 50 mm. The size distribution of the UCA was measured with a CasyTM Cell counter.
Results: The simulation predicted a pressure threshold that was an order of magnitude higher than that determined experimentally. However, all other predictions were consistent with the experimental observations. It was predicted that: (1) exciting the agent with chirps would produce stronger subharmonic response relative to those produced by sine-bursts; (2) increasing the fractional bandwidth of coded-chirp excitation would increase the sensitivity of subharmonic imaging; and (3) coded-chirp would increase axial resolution. The experimental results revealed that subharmonic-to-fundamental ratios obtained with chirps were 5.7 dB higher than those produced with sine-bursts of similar duration. The axial resolution achieved with 20% fractional bandwidth chirps was approximately twice that achieved with 4% fractional bandwidth sine-bursts.
Conclusions: The coded-chirp method is a suitable excitation strategy for subharmonic IVUS imaging. At the 20 MHz transmission frequency and 20% fractional bandwidth, coded-chirp excitation appears to represent the ideal tradeoff between subharmonic strength and axial resolution.

Microvolt T‐Wave Alternans for Risk Stratification in Athletes with Ventricular Arrhythmias: Correlation with Programmed Ventricular Stimulation

by Rita Pizzi

Decodifica di segnali neurali naturali attraverso una rete neurale artificiale/ Decoding natural neural signals by means of an Artificial Neural Network

by Rita Pizzi

The link includes presentation of the research activity and a full paper

Abbiamo costruito un ibrido costituito da una rete di cellule neurali umane che comanda un robot in grado di muoversi... more Abbiamo costruito un ibrido costituito da una rete di cellule neurali umane che comanda un robot in grado di muoversi in base ai comandi da noi impartiti.

Design Approach for a Low Power Video Decoder

by Fabrício Lélis

This paper presents a detailed description of
the design of a Low Power, SystemC-RTL, OCP-IP
compliant... more This paper presents a detailed description of
the design of a Low Power, SystemC-RTL, OCP-IP
compliant MPEG-4 decoder IP-core, named Terpsicore. The
Terpsicore was designed for use in embedded systems where
low cost, high performance and power efficiency are
important. This design supports simple profile L0 with two
external memories, was manufactured using a 0.35um
CMOS 4ML technology and has a die of 49mm² comprising
48095 gates. It consumes 115mW at 25MHz when video
encoding of QCIF at 15fps with a voltage supply of 3.3V.
Compared with other implementations of the MPEG-4
standard available in the market, the Terpsicore presents
better energy efficiency and this paper shows how this was
achieved.

SPVR: An IP core for Real-Time Speaker Verification

by Fabrício Lélis

Alphanumeric passwords, identification via either chip cards or biometric parameters as iris pattern, fingerprints and... more Alphanumeric passwords, identification via either chip cards or biometric parameters as iris pattern, fingerprints and voice are used to control access to confidential information and to restricted areas as well as to several types of automated money transactions. This paper aims at presenting an IP core whose purpose is to perform real-time speaker verification. The IP core can be used as part of a system to check if the speaker is really the one (he or she) who claims to be. For each speaker, the IP core needs a codebook which is obtained by off-line training. Linear Prediction Coding (LPC) and Vector Quantization (VQ) techniques are employed. The IP core was designed to process the signal in real time, meaning that, as soon as the IP core has gathered enough data to reach a certain confidence level, it will output its decision.

Fifty Years of Artificial Reverberation

by Julian Parker

Co-authored with Vesa Välimäki, Lauri Savioja, Julius Smith and Jonathan Abel.

The first artificial reverberation algorithms were proposed in the early 1960s, and new, improved algorithms are... more The first artificial reverberation algorithms were proposed in the early 1960s, and new, improved algorithms are published regularly. These algorithms have been widely used in music production since the 1970s, and now find applications in new fields, such as game audio. This overview article provides a unified review of the various approaches to digital artificial reverberation. The three main categories have been delay networks, convolution-based algorithms, and physical room models. Delay-network and convolution techniques have been competing in popularity in the music technology field, and are often employed to produce a desired perceptual or artistic effect. In applications including virtual reality, predictive acoustic modeling, and computer-aided design of acoustic spaces, accuracy is desired, and physical models have been mainly used, although, due to their computational complexity, they are presently mainly used for simplified geometries or to generate reverberation impulse responses for use with a convolution method. With the increase of computing power, all these approaches will be available in real time. A recent trend in audio technology is the emulation of analog artificial reverberation units, such as spring reverberators, using signal processing algorithms. As a case study we present an improved parametric model for a spring reverberation unit.

High-frequency subharmonic emission with chirp-coded excitation: implications for imaging

by Himanshu Shekhar

There is growing interest in developing techniques to assess the structure and function of microvasculature, to enable... more There is growing interest in developing techniques to assess the structure and function of microvasculature, to enable clinical diagnosis and to gain insights into disease pathology. High-frequency subharmonic imaging is an emerging technique that can visualize the microvasculature with high specificity. However, the sensitivity of high-frequency subharmonic imaging is compromised because of the pressure threshold for subharmonic behavior, which may limit its potential for preclinical and clinical imaging. The goal of this work was to demonstrate that the sensitivity of subharmonic imaging could be improved by rectangular apodization and chirp-coding of the excitation pulse. We report an experimental study carried out at 20-MHz transmit frequency to compare the efficacy of narrowband sine bursts and coded-chirps towards generating subharmonics. It was demonstrated that chirp-coding of the excitation pulse could generate stable subharmonic signals for excitation bandwidths of 10-20%. The threshold for onset of subharmonic behavior was lowest when rectangularwindowed excitation pulses were employed. The subharmonic to fundamental ratio of RF spectra using coded chirps was up to 5.7 dB higher for sine bursts, and the axial resolution obtained with chirp-coded excitation was up to twofold better compared to that obtained using sine bursts. At 20-MHz transmit frequency, 20% bandwidth rectangular chirp-coded pulse appears to be a good tradeoff between sensitivity and axial resolution.

Steepest Descent Least Mean Square Algorithm (LMS) Based Adaptive Filter for Noise Cancellation in Speech Signals

by Udayanto Dwi Atmojo

Presented in 6th SEAMS GMU International Conference on Mathematics and Its Applications 2011 in Yogyakarta, Indonesia, July 12-15, 2011

This paper considers Least Mean Square (LMS) algorithm to subsequently modify adaptive filter weights. The... more This paper considers Least Mean Square (LMS) algorithm to subsequently modify adaptive filter weights. The corresponding filter is used to cancel noise caused by diesel engine interference contained in speech signal. The design is then implemented on LabView software. The simulation shows that the design can reduce interference, thus increasing signal to noise ratio (SNR) of the speech signal by more than 100%

ECG Signal Preprocessing using LabView : LMS based Adaptive Filter for Powerline Interference Cancellation

by Udayanto Dwi Atmojo

Published in International Conference on Information Technology and Electrical Engineering (CITEE) 2011 in Yogyakarta, Indonesia on 20 July 2011. Co authored by Dr Eka Firmansyah

This paper considers Least Mean Square (LMS) algorithm to subsequently modify adaptive filter wieghts. The... more This paper considers Least Mean Square (LMS) algorithm to subsequently modify adaptive filter wieghts. The corresponding filter is used to cancel noise caused by powerline interference contained in Electrocardiograph (ECG) signal. The design is then implemented on LabView software. The simulation shows that the design can reduce powerline interference. Average powerline noise power contained in the signal is attenuated by more than 20 times.

Establishing “Zone of Silence”: LMS Adaptive Filter Implementation for Noise Cancellation

by Udayanto Dwi Atmojo

Published in International Conference on Informatics for Development (ICID) 2011 in Yogyakarta, Indonesia on 26th November 2011

This paper considers an implementation of Least
Mean Square (LMS) adaptive filter for noise cancellation. In... more This paper considers an implementation of Least
Mean Square (LMS) adaptive filter for noise cancellation. In this
paper, the adaptive filter is used to create a “Zone of Silence”.
The paper considers the use of LMS adaptive filter to cancel
engine noise in a target area by generating a signal that will
interfere destructively with the noise signal, hence cancels the
noise introduced in the target area. The proposed model is
simulated using LabView software. The resuts show that the
proposed model can cancel out noise average power up to 7900
times.

An Image Processing Technique for the Translation of ASL Finger-Spelling to Digital Audio or Text. Paper Presented at the Instructional Technology and Education of the …

by Chance Glenn

SIGNAL PROCESSING FOR A LASER BASED AIR DATA SYSTEM IN COMMERCIAL AIRCRAFTS

by Theodoros Semertzidis

On the development of variable length Teager energy operator (VTEO)

by Vikrant Tomar

Digital signal processing for gene prediction

by Vikrant Tomar

Experimental Media Horizons - Syncretic and Subversive Practices

by Joey Bargsten

Virtual Presentation: ICERI 2009

This paper formed part of the foundation for my book, Hybrid Forms and Syncretic Horizons (2011), available on Amazon... more This paper formed part of the foundation for my book, Hybrid Forms and Syncretic Horizons (2011), available on Amazon at [http://badmindtime.nfshost.com/amazon2].

Performative media--including video jamming, live and networked media collaboration, and mobile-device based performance--is reaching a critical mass in digital culture. In Experimental Media Horizons, we will examine a number of outlying practices where the materials of digital culture are beginning to coalesce, and place current activity into a broader historical and aesthetic context. Included is an overview of tech requirements and performance suggestions for developing your own course.