MedWorm: Biomedical Engineering

Editorial Board

Medical Engineering and Physics — Tue, 14 May 2013 02:10:04 +0100

(Source: Medical Engineering and Physics)

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Detecting fixation on a target using time-frequency distributions of a retinal birefringence scanning signal

BioMedical Engineering OnLine — Mon, 13 May 2013 04:00:00 +0100

Conclusion: Joint time-frequency analysis is a powerful tool in the detection of eye alignment, even in a noisy environment. The method is applicable to similar situations, where short-lasting diagnostic events need to be detected in time series acquired by means of scanning some substrate along a specific path. (Source: BioMedical Engineering OnLine)

Methods of measuring the iridocorneal angle in tomographic images of the anterior segment of the eye

BioMedical Engineering OnLine — Fri, 10 May 2013 04:00:00 +0100

Conclusions: The study proved that the proposed method of measuring the minimum distance between the iris and the cornea within the adopted area is the most effective in the classification of the iridocorneal angle in patients with a high degree of pathology of all the compared measurement methods based on tomographic images. However, it requires fully automated measurement. (Source: BioMedical Engineering OnLine)

Superior Lubricant Offers Hope For Osteoarthritis Sufferers

Health News from Medical News Today — Tue, 07 May 2013 08:00:00 +0100

A team of researchers led by a Boston University Biomedical Engineer has developed a new joint lubricant that could bring longer lasting relief to millions of osteoarthritis sufferers. The new synthetic polymer supplements synovial fluid, the natural lubricant in joints, and works better than comparable treatments currently available. According to Boston University Professor of Biomedical Engineering Mark W... (Source: Health News from Medical News Today)

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Volumetric three-dimensional intravascular ultrasound visualization using shape-based nonlinear interpolation

BioMedical Engineering OnLine — Tue, 07 May 2013 04:00:00 +0100

Conclusions: This novel 3D IVUS visualization strategy has the potential to improve ultrasound imaging of vascular structure information, particularly atheroma determination. Improved volumetric 3D visualization with accurate acoustic backscatter information can help with ultrasound molecular imaging of atheroma component distribution. (Source: BioMedical Engineering OnLine)

Editorial Board

Medical Engineering and Physics — Wed, 01 May 2013 04:00:00 +0100

(Source: Medical Engineering and Physics)

Neurovascular coupling: in vivo optical techniques for functional brain imaging

BioMedical Engineering OnLine — Tue, 30 Apr 2013 04:00:00 +0100

Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current...

Detection of the valvular split within the second heart sound using the reassigned smoothed pseudo Wigner-Ville distribution

BioMedical Engineering OnLine — Tue, 30 Apr 2013 04:00:00 +0100

Background In this paper, we developed a novel algorithm to detect the valvular split between the aortic and pulmonary components in the second heart sound which is a valuable medical information.Methods The algorithm is based on the Reassigned smoothed pseudo Wigner--Ville distribution which is a modified time--frequency distribution of the Wigner--Ville distribution. A preprocessing amplitude recovery procedure is carried out on the analysed heart sound to improve the readability of the time--frequency representation. The simulated S2 heart sounds were generated by an overlapping frequency modulated chirp--based model at different valvular split durations.Results Simulated and real heart sounds are processed to highlight the performance of the proposed approach. The algorithm is also val...

Cellular Secrets May Be Revealed By New Imaging Technology

Health News from Medical News Today — Mon, 29 Apr 2013 08:00:00 +0100

Researchers have married two biological imaging technologies, creating a new way to learn how good cells go bad. "Let's say you have a large population of cells," said Corey Neu, an assistant professor in Purdue University's Weldon School of Biomedical Engineering. "Just one of them might metastasize or proliferate, forming a cancerous tumor. We need to understand what it is that gives rise to that one bad cell... (Source: Health News from Medical News Today)

New Imaging Technology Could Reveal Cellular Secrets

Health News from Medical News Today — Sat, 27 Apr 2013 07:00:00 +0100

Researchers use nasal lining to breach blood/brain barrier

EurekAlert! - Social and Behavioral Science — Wed, 24 Apr 2013 04:00:00 +0100

(Massachusetts Eye and Ear Infirmary) Using mucosa, or the lining of the nose, researchers in the department of Otology and Laryngology at the Massachusetts Eye and Ear/Harvard Medical School and the Biomedical Engineering Department of Boston University have demonstrated what may be the first known method to permanently bypass the blood-brain barrier, thus opening the door to new treatment options for those with neurodegenerative and CNS disease. Their study is published on PLOS ONE. (Source: EurekAlert! - Social and Behavioral Science)

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In vivo MRI-based simulation of fatigue process: a possible trigger for human carotid atherosclerotic plaque rupture

BioMedical Engineering OnLine — Tue, 23 Apr 2013 04:00:00 +0100

Conclusion: Fatigue process seems to explain the development of cracks in FC, which ultimately lead to plaque rupture. (Source: BioMedical Engineering OnLine)

Bone formation in rabbit cancellous bone explant culture model is enhanced by mechanical load

BioMedical Engineering OnLine — Fri, 19 Apr 2013 04:00:00 +0100

Background: When studying and designing an artificial bone in vitro with similar features and functionality of natural bone by tissue engineering technology, the culturing environment, especially the mechanical environment is supposed to be an important factor, because a suitable mechanical environment in vitro may improve the adaptability of the planted-in tissue engineering bone in the body. Unfortunately, up to now, the relationship between mechanical stimuli and natural bone growth has not yet been precisely determined, and it is so imperative for a prior study on effect of mechanical loading on growth of the natural bone cultured in vitro. Methods: Under sterile conditions, explant models of rabbit cancellous bone with 3 mm in thickness and 8 mm in diameter were prepared and cultured ...

Microneedle Adhesive More Than 3x Stronger Than Surgical Staples In Skin Graft Fixation

Health News from Medical News Today — Thu, 18 Apr 2013 08:00:00 +0100

A parasitic worm may hold the answer to keeping skin grafts firmly in place over wounds, according to a new study by researchers at Brigham and Women's Hospital (BWH). The study was published in the journal Nature Communications. The research team, led by Jeffrey Karp, PhD, BWH Division of Biomedical Engineering, Department of Medicine, senior study author, invented a microneedle inspired by Pomphorhynchus laevis, a spiny-headed worm that lives in the intestines of its hosts, in this case fish... (Source: Health News from Medical News Today)

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Review of "orthopaedic biomechanics" edited by Beth A. Winkelstein

BioMedical Engineering OnLine — Thu, 18 Apr 2013 04:00:00 +0100

Orthopaedic Biomechanics was released in 2012 and edited by Beth A. Winkelstein, PhD. The list price of the book ($179.95) is comparable with similar books published in this field. This text is intended for both the novice and established researcher working the field of orthopaedic biomechanics. However, this book assumes that the reader has some basic knowledge about biomechanics, finite element modeling, and biomaterials used in orthopedic surgery. Composed of twenty-one chapters with approximately 3,000 references, "Orthopaedic Biomechanics" provides an exhaustive literature review of the most current published data in orthopaedic biomechanical engineering. This work focuses on the vast and complex nature of the field of orthopedic biomechanics that challenges both researchers and clini...

Review of ¿orthopaedic biomechanics¿ edited by Beth A. Winkelstein

BioMedical Engineering OnLine — Thu, 18 Apr 2013 04:00:00 +0100

This article is a review of the book “orthopaedic biomechanics” edited by Beth A. Winkelstein. This book (hardcover) was published by CRC Press, Taylor & Francis Group, FL in 2012. The contents of the book and its relevance to orthopedic research or practice is discussed in this invited review. (Source: BioMedical Engineering OnLine)

Motor recovery monitoring using acceleration measurements in post acute stroke patients

BioMedical Engineering OnLine — Tue, 16 Apr 2013 04:00:00 +0100

Conclusion: A wireless accelerometer based 'hot stroke' monitoring system is developed to monitor the motor recovery in acute-stroke patients. It has been shown to monitor stroke patients continuously, which has not been possible so far with high reliability. (Source: BioMedical Engineering OnLine)

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Dependence of model-based RSA accuracy on higher and lower implant surface model quality

BioMedical Engineering OnLine — Tue, 16 Apr 2013 04:00:00 +0100

Conclusion: The data suggest that the application of lower resolution RE models for MBRSA is a viable alternative method for the in vivo measurement of implant migration, in particular for implants with non symmetrical geometries (total knee arthroplasty). Implants with larger length to width aspect ratio (total hip arthroplasty) may require high resolution RE models in order to achieve acceptable accuracy. Conversely, for some axis the bias for translation are clearly worse for translation, and are marginally better for rotations using the lower resolution RE models instead of the higher ones. However, performed box plots ranges were well within what has been reported in the literature. The observed lower accuracy and precision of the measurements for hip stem components for rotations abo...

IEEE Transactions on Signal Processing publication information

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

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Time-of-Arrival Estimation Based on Information Theoretic Criteria

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The possibility to accurately localize tags by using wireless techniques is of great importance for several emerging applications in the Internet of Things. Precise ranging can be obtained with ultra wideband (UWB) impulse radio (IR) systems, where short impulses are transmitted, and their time-of-arrival (ToA) is estimated at the receiver. Due to the presence of noise and multipath, the estimator has the difficult task of discriminating the time intervals where the received waveform is due to noise only, by those where there are also signal components. Common low-complexity methods use an energy detector (ED), whose output is compared with a threshold, to discriminate the time intervals containing noise only from those containing signal plus noise. Optimal threshold design for these metho...

Wavelet Denoising Based on the MAP Estimation Using the BKF Prior With Application to Images and EEG Signals

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a novel nonparametric Bayesian estimator for signal and image denoising in the wavelet domain. This approach uses a prior model of the wavelet coefficients designed to capture the sparseness of the wavelet expansion. A new family of Bessel K Form (BKF) densities are designed to fit the observed histograms, so as to provide a probabilistic model for the marginal densities of the wavelet coefficients. This paper first shows how the BKF prior can characterize images belonging to Besov spaces. Then, a new hyper-parameters estimator based on EM algorithm is designed to estimate the parameters of the BKF density; and, it is compared with a cumulants-based estimator. Exploiting this prior model, another novel contribution is to design a Bayesian denoiser based on the Maximum A...

Space-Time-Frequency (STF) MIMO Communication Systems With Blind Receiver Based on a Generalized PARATUCK2 Model

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In this paper, we first propose a generalized fourth-order PARATUCK2 tensor model for multiple-input multiple-output (MIMO) communication systems with space-time-frequency (STF) spreading-multiplexing. The core of the proposed PARATUCK2 model is composed of two third-order interaction tensors that define a joint time and frequency allocation of the data streams to the transmit antennas, thus allowing to adjust the multiplexing degree and spreading redundancy in three domains: space (transmit antennas), time (blocks) and frequency (subcarriers). Then, we investigate the identifiability of the PARATUCK2-STF MIMO system by deriving sufficient conditions which are translated into design recommendations for the STF allocation structure. In particular, essential uniqueness is discussed by interp...

Improvement of TDOA Position Fixing Using the Likelihood Curvature

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

A conventional multilateration is a two-step process where, in the first step the time difference of arrivals (TDOA) of a signal at multiple sensors are estimated, and in the second step, these TDOAs are used in some position fixing technique to estimate the location of an emitter. Several estimators have been proposed over the years for the estimation of the TDOAs. Many techniques have been proposed for position fixing as well. Much of the research on position fixing has been focused on obtaining a simplified closed form solution. For the unknown deterministic signal model, Stein had derived the maximum-likelihood estimator (MLE) for the TDOA between two sensors, which is the peak location of the cross-correlation function. Since the asymptotic variance of an MLE approaches the Cramer-Rao...

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Low-Complexity DOA Estimation Based on Compressed MUSIC and Its Performance Analysis

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a new computationally efficient method for direction-of-arrival (DOA) estimation with arbitrary arrays. The total angular field-of-view is first divided into several small sectors and the original noise subspace exploited by the multiple signal classification (MUSIC) algorithm is mapped from one sector to the other sectors by a Hadarmard product transformation. This transformation gives a new noise-like subspace cluster (NLSC), whose intersection is found to be simultaneously orthogonal to the steering vectors associated with the true DOAs and several virtual DOAs. Based on such a multiple orthogonality, a novel compressed MUSIC (C-MUSIC) spatial spectrum at hand is derived. Unlike MUSIC with tremendous spectral search, C-MUSIC involves a limited search over only one se...

Efficient Soft Decision Fusion Rule in Cooperative Spectrum Sensing

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In cognitive radio (CR), the soft decision fusion (SDF) rule plays a critical role in cooperative spectrum sensing (CSS). However, the computational cost on obtaining efficient SDF rule becomes infeasible even with a small number of cooperative users. In this paper, the efficiency of SDF rule in inhomogeneous background is studied from the perspective of quantization theory. We formulate the calculation of sensing performance including the probabilities of detection and false alarm when regarding both i) the quantization impact and ii) the inhomogeneous background, and then conclude a condition under which the sensing performance can be calculated by the fast Fourier transform (FFT). Based on this condition, two novel quantization schemes with two optimization methods are proposed to guara...

Modeling and Estimation of Covariance of Replicated Modulated Cyclical Time Series

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper introduces the novel class of modulated cyclostationary processes, a class of nonstationary processes exhibiting frequency coupling, and proposes a method of their estimation from repeated trials. Cyclostationary processes also exhibit frequency correlation but have Loève spectra whose support lies only on parallel lines in the dual-frequency plane. Such extremely sparse structure does not adequately represent many biological processes. Thus, we propose a model that, in the time domain, modulates the covariance of cyclostationary processes and consequently broadens their frequency support in the dual-frequency plane. The spectra and the cross-coherence of the proposed modulated cyclostationary process are first estimated using multitaper methods. A shrinkage procedure is ...

Robustness Analysis of Spatial Time-Frequency Distributions Based on the Influence Function

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Standard spatial time-frequency distribution (STFD) estimators, derived based on the Gaussian noise assumption, are known to have poor performance in the case of impulsive noise. Recently, different STFD estimators have been proposed, which, based on simulations, are claimed to be robust. In this paper, we provide an influence function robustness analysis of STFD estimators. We derive the influence functions for the asymptotic and for the finite-sample case and study robustness of the standard, as well as for some recently proposed robust STFD estimators. The empirical influence function gives practitioners a simple way to pre-select STFD estimators for their scenario. Our analysis confirms that, unlike for the standard estimator, the proposed robust estimators yield a bounded influence fu...

The Performance of a Matched Subspace Detector That Uses Subspaces Estimated From Finite, Noisy, Training Data

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

We analyze the performance of a matched subspace detector (MSD) where the test signal vector is assumed to reside in an unknown, low-rank $k$ subspace that must be estimated from finite, noisy, signal-bearing training data. Under both a stochastic and deterministic model for the test vector, subspace estimation errors due to limited training data degrade the performance of the standard plug-in detector, relative to that of an oracle detector. To avoid some of this performance loss, we utilize and extend recent results from random matrix theory (RMT) that precisely quantify the quality of the subspace estimate as a function of the eigen-SNR, dimensionality of the system, and the number of training samples. We exploit this knowledge of the subspace estimation accuracy to derive from first-pr...

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Cramér-Rao-Induced Bounds for CANDECOMP/PARAFAC Tensor Decomposition

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a Cramér-Rao lower bound (CRLB) on the variance of unbiased estimates of factor matrices in Canonical Polyadic (CP) or CANDECOMP/PARAFAC (CP) decompositions of a tensor from noisy observations, (i.e., the tensor plus a random Gaussian i.i.d. tensor). A novel expression is derived for a bound on the mean square angular error of factors along a selected dimension of a tensor of an arbitrary dimension. The expression needs less operations for computing the bound, $O(NR^{6})$, than the best existing state-of-the art algorithm, $O(N^{3}R^{6})$ operations, where $N$ and $R$ are the tensor order and the tensor rank. Insightful expressions are derived for tensors of rank 1 and rank 2 of arbitrary dimension and for tensors of arbitrary dimension and rank, where two factor...

Performance of the Delsarte-Goethals Frame on Clustered Sparse Vectors

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The Delsarte-Goethals frame (DGF) has been proposed for deterministic compressive sensing of sparse and compressible signals. Results in compressive sensing theory show that the DGF enables successful recovery of an overwhelming majority of sufficiently sparse signals. However, these results do not give a characterization of the sparse vectors for which the recovery procedure fails. In this paper, we present a formal analysis of the DGF that highlights the presence of clustered sparse vectors within its null space. This in turn implies that sparse recovery performance is diminished for sparse vectors that have their nonzero entries clustered together. Such clustered structure is present in compressive imaging applications, where commonly-used raster scannings of 2-D discrete wavelet transf...

Extension of SBL Algorithms for the Recovery of Block Sparse Signals With Intra-Block Correlation

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

We examine the recovery of block sparse signals and extend the recovery framework in two important directions; one by exploiting the signals' intra-block correlation and the other by generalizing the signals' block structure. We propose two families of algorithms based on the framework of block sparse Bayesian learning (BSBL). One family, directly derived from the BSBL framework, require knowledge of the block structure. Another family, derived from an expanded BSBL framework, are based on a weaker assumption on the block structure, and can be used when the block structure is completely unknown. Using these algorithms, we show that exploiting intra-block correlation is very helpful in improving recovery performance. These algorithms also shed light on how to modify existing algorithms or d...

Projection Design for Statistical Compressive Sensing: A Tight Frame Based Approach

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In this paper, we develop a framework to design sensing matrices for compressive sensing applications that lead to good mean squared error (MSE) performance subject to sensing cost constraints. By capitalizing on the MSE of the oracle estimator, whose performance has been shown to act as a benchmark to the performance of standard sparse recovery algorithms, we use the fact that a Parseval tight frame is the closest design - in the Frobenius norm sense - to the solution of a convex relaxation of the optimization problem that relates to the minimization of the MSE of the oracleestimator with respect to the equivalent sensing matrix, subject to sensing energy constraints. Based on this result, we then propose two sensing matrix designs that exhibit two key properties: i) the designs are close...

Maximally Robust Capon Beamformer

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The standard Capon beamformer (SCB) achieves the maximum output signal-to-interference-plus-noise ratio in the error-free case. However, estimation errors of the signal steering vector and the array covariance matrix can result in severe performance deteriorations of the SCB, especially if the training data contains the desired signal component. A popular technique to improve the robustness against model errors is to compute the Capon beamformer with the maximum output power, considering an uncertainty set for the signal steering vector. However, maximizing the total beamformer output power may result in an insufficient suppression of interferers and noise. As an alternative approach to mitigate the detrimental effect of model errors, we propose to compute the Capon beamformer with the min...

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On Cyclostationarity Based Spectrum Sensing Under Uncertain Gaussian Noise

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Detection of cyclostationary primary user (PU) signals in colored Gaussian noise for cognitive radio systems is considered based on looking for single or multiple cycle frequencies at single or multiple time lags in the cyclic autocorrelation function (CAF) of the noisy PU signal. We explicitly exploit the knowledge that under the null hypothesis of PU signal absent, the measurements originate from possible colored Gaussian noise with unknown correlation function. Our formulation allows us to simplify the spectrum sensing detector and obviates the need for estimating an unwieldy covariance matrix needed in some prior works. We consider both single and multiple antenna receivers, and both nonconjugate and conjugate CAFs. A performance analysis of the proposed detector is carried out. Suppor...

Learning Incoherent Dictionaries for Sparse Approximation Using Iterative Projections and Rotations

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This article deals with learning dictionaries for sparse approximation whose atoms are both adapted to a training set of signals and mutually incoherent. To meet this objective, we employ a dictionary learning scheme consisting of sparse approximation followed by dictionary update and we add to the latter a decorrelation step in order to reach a target mutual coherence level. This step is accomplished by an iterative projection method complemented by a rotation of the dictionary. Experiments on musical audio data and a comparison with the method of optimal coherence-constrained directions (mocod) and the incoherent k-svd (ink-svd) illustrate that the proposed algorithm can learn dictionaries that exhibit a low mutual coherence while providing a sparse approximation with better signal-to-no...

The Feasibility Conditions for Interference Alignment in MIMO Networks

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Interference alignment (IA) has attracted great attention in the last few years for its breakthrough performance in interference networks. However, despite the numerous works dedicated to IA, the feasibility conditions of IA remains unclear for most network topologies. The IA feasibility analysis is challenging as the IA constraints are sets of high-degree polynomials, for which no systematic tool to analyze the solvability conditions exists. In this work, by developing a new mathematical framework that maps the solvability of sets of polynomial equations to the linear independence of their first-order terms, we propose a sufficient condition that applies to MIMO interference networks with general configurations. We have further proved that this sufficient condition coincides with the nece...

FastICA Algorithm: Five Criteria for the Optimal Choice of the Nonlinearity Function

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Using an infinite sample, the contrast function and the FastICA algorithm are deterministic. In the practical case, we have only a finite sample. Then the contrast function and the FastICA algorithm become estimators of the deterministic case. This paper provides a unified study of the deflation FastICA algorithm assuming a finite or an infinite sample. We consider four random probability distributions based on the finite sample, and construct four FastICA estimators. We show that under mild conditions, each of these estimators are equal to a local minimizer of the contrast function with respect to the underlying random probability distribution. Making use of the existing results of M-estimators, we give a rigorous analysis of the asymptotic errors of FastICA estimators. We derive five cri...

Fast Algorithms for Optimal Link Selection in Large-Scale Network Monitoring

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The robustness and integrity of IP networks require efficient tools for traffic monitoring and analysis, which scale well with traffic volume and network size. We address the problem of optimal large-scale monitoring of computer networks under resource constraints. Specifically, we consider the task of selecting the “best” subset of at most $K$ links to monitor, so as to optimally predict the traffic load at the remaining ones. Our notion of optimality is quantified in terms of the statistical error of network traffic predictors. The optimal monitoring problem at hand is akin to certain combinatorial constraints, which render the algorithms seeking the exact solution impractical. We develop a number of fast algorithms that improve upon existing algorithms in terms of computat...

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Generalized CFAR Property and UMP Invariance for Adaptive Signal Detection

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In this paper we consider adaptive detection of a signal embedded in additive disturbance whose multivariate distribution belongs to a very general class, including many statistical models commonly adopted for radar disturbance. We introduce the concept of generalized Constant False Alarm Rate (CFAR) and show that a class of receivers sharing some invariances complies with the quoted property. Then, we devise the Generalized Likelihood Ratio Test (GLRT) and prove that, under some mild technical conditions, it coincides with that obtained under the Gaussian assumption for the observations. We also deal with the existence of the Uniformly Most Powerful Invariant (UMPI) detector either using the Wijsman theorem or directly computing the maximal invariant Likelihood Ratio (LR). At the analysis...

DVB-T Passive Radar Signal Processing

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This study presents a scheme for pre-processing both the reference and surveillance signals obtained by the passive radar to mitigate the effects of the ambiguities and the clutter in range-Doppler processing. The effectiveness of our proposed scheme in enhancing target detection is demonstrated using real-world data from an (Australian) 8k-mode DVB-T system. A 29 dB reduction in residual ambiguity levels over existing techniques is observed, and a 36 dB reduction over standard matched filtering; with only a 1 dB reduction in the zero-delay, zero-Doppler peak. (Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing Edics

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing information for authors

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

Open Access

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

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Call for papers: IEEE Signal Processing Magazine - Special Issue on Recent Advances in Synthetic Aperture Radar Imaging

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This Special Issue seeks to review progress in synthetic aperture radar imaging which has been made possible through new algorithms and enabling hardware. It serves to capture the approaches propelling recent cutting-edge research and scholarly activities in SAR Imagery. SAR has become a valuable tool for civilian remote sensing applications as well as for military surveillance and reconnaissance. SAR operations can take place in all weather and times. SAR data can provide key information about the scene which can be extracted e.g. from the polarimetric features, the phase variation over time, and the reflectivity dependency on frequency. A wide variety of air- and space based sensors for long and short range operation has been realized, operating at frequencies extending from VHF to the u...

IEEE Xplore Digital Library

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

[Blank page - back cover]

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

The latest Elsevier Engineering news and information. Join now @elseviereng on Twitter and on Facebook http://ow.ly/jQZfC

Elsevier Updates: Engineering — Fri, 12 Apr 2013 12:05:00 +0100

Join the conversation. (Source: Elsevier Updates: Engineering)

Brain extraction from cerebral MRI volume using a hybrid level set based active contour neighborhood model

BioMedical Engineering OnLine — Fri, 12 Apr 2013 04:00:00 +0100

Conclusions: An automatic method of brain extraction from cerebral MRI volume was achieved and produced competitively accurate results. (Source: BioMedical Engineering OnLine)

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Three-dimensional reconstruction of blood vessels in the rabbit eye by X-ray phase contrast imaging

BioMedical Engineering OnLine — Thu, 11 Apr 2013 04:00:00 +0100

Conclusions: XPCI provided a feasible means to determine the structure of the blood vessels in the eye. We were able to determine the diameters and morphological characteristics of the vessels from both 2D images and the 3D model. By analyzing the images, we obtained measurements of the density distribution of the microvasculature, and this approach may provide valuable reference information prior to glaucoma filtration surgery. (Source: BioMedical Engineering OnLine)

Advancing Tissue Engineering By Building Better Blood Vessels

Health News from Medical News Today — Mon, 08 Apr 2013 07:00:00 +0100

One of the major obstacles to growing new organs - replacement hearts, lungs and kidneys - is the difficulty researchers face in building blood vessels that keep the tissues alive, but new findings from the University of Michigan could help overcome this roadblock. "It's not just enough to make a piece of tissue that functions like your desired target," said Andrew Putnam, U-M associate professor of biomedical engineering. "If you don't nourish it with blood by vascularizing it, it's only going to be as big as the head of a pen... (Source: Health News from Medical News Today)

Extremely low flow tracheal gas insufflation of helium-oxygen mixture improves gas exchange in a rabbit model of piston-type high-frequency oscillatory ventilation

BioMedical Engineering OnLine — Mon, 08 Apr 2013 04:00:00 +0100

ObjectiveThe purpose of this study was to show the effects of the tracheal gas insufflation (TGI) technique on gas exchange using helium-oxygen mixtures during high-frequency oscillatory ventilation (HFOV). We hypothesized that a helium-oxygen mixture delivered into the trachea using the TGI technique (0.3 L/min) would enhance gas exchange during HFOV. Methods: Three rabbits were prepared and ventilated by HFOV with carrier 70% helium/oxygen or 70% nitrogen/oxygen gas mixture with TGI in a crossover study. Changing the gas mixture from nitrogen70% to helium70% and back was performed three times per animal with constant ventilation parameters. Results: Compared with the nitrogen-oxygen mixture, the helium-oxygen mixture of TGI reduced PaCO2 by 7.6 mmHg (p (Source: BioMedical Engineerin...

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Fibroin and fibroin blended three-dimensional scaffolds for rat chondrocyte culture

BioMedical Engineering OnLine — Mon, 08 Apr 2013 04:00:00 +0100

Conclusion: Addition of collagen and gelatin to SF solution not only improved the mechanical properties of the scaffolds but also provided an effective biomaterial constructs for chondrocyte growth and chondrocytic phenotype maintenance. Therefore, SF/C and SF/G showed a great potential as a desirable biomaterial for cartilage tissue engineering. (Source: BioMedical Engineering OnLine)

Multipurpose contrast enhancement on epiphyseal plates and ossification centers for bone age assessment

BioMedical Engineering OnLine — Mon, 08 Apr 2013 04:00:00 +0100

Conclusions: The proposed MBOBHE outperforms other existing methods regarding comprehensive performance of histogram equalization. All the features which are pertinent to bone age assessment are more protruding relative to other methods; this has shorten the required evaluation time in manual bone age assessment using TW method. While the accuracy remains unaffected or slightly better than using unprocessed original image. The holistic properties in terms of brightness preservation, detail preservation and contrast enhancement are simultaneous taken into consideration and thus the visual effect is contributive to manual inspection. (Source: BioMedical Engineering OnLine)

Effect of pressure and padding on motion artifact of textile electrodes

BioMedical Engineering OnLine — Mon, 08 Apr 2013 04:00:00 +0100

Conclusion: From the results of this study, guidelines for improving electrode design regarding padding and pressure can be formulated as paddings are a necessary part of the system for reducing the motion artifact, and further, their effect maximises between 15 mmHg and 20 mmHg of exerted pressure. In addition, we present new methods for evaluating electrode sensitivity to motion, utilizing the detection of noise peaks that fall into the same frequency band as R-peaks. (Source: BioMedical Engineering OnLine)

Clinical evaluation of a wireless ECG sensor system for arrhythmia diagnostic purposes

Medical Engineering and Physics — Fri, 05 Apr 2013 04:00:00 +0100

Abstract: In a clinical study, a novel wireless electrocardiogram (ECG) recorder has been evaluated with regard to its ability to perform arrhythmia diagnostics. As the ECG recorder will detect a “non-standard” ECG signal, it has been necessary to compare those signals to “standard” ECG recording signals in order to evaluate the arrhythmia detection ability of the new system. Simultaneous recording of ECG signals from both the new wireless ECG recorder and a conventional Holter recorder was compared by two independent cardiology specialists with regard to signal quality for performing arrhythmia diagnosis. In addition, calculated R–R intervals from the two systems were correlated. A total number of 16 patients participated in the study. It can be considered that recorded ECG sign...

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Elsevier Updates: Engineering — Wed, 03 Apr 2013 00:00:00 +0100

Find out more (Source: Elsevier Updates: Engineering)

BU student receives 2013 Joanna M. Nicolay Melanoma Foundation scholarship award

EurekAlert! - Medicine and Health — Tue, 02 Apr 2013 04:00:00 +0100

(Boston University Medical Center) The Joanna M. Nicolay Melanoma Foundation presented Elizabeth Shenk, a student in both the Boston University Biomedical Engineering Department and the Boston University School of Medicine Pharmacology Training Program with one of 10, nationally competitive, 2013 "Research Scholar Awards." (Source: EurekAlert! - Medicine and Health)

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Editorial Board

Medical Engineering and Physics — Mon, 01 Apr 2013 04:00:00 +0100

(Source: Medical Engineering and Physics)

Publication ethics: redundancy in publication

Medical Engineering and Physics — Mon, 01 Apr 2013 04:00:00 +0100

I have been Editor of this Journal for a little over a year, and in that time I have, with the support of the Editorial Board, Journal Manager and staff in the Editorial Office, processed more than 700 submissions, in addition to those already in the system when I took over from my predecessor. Whilst the majority of those articles were reporting original work, regrettably a number showed some evidence of redundancy, and indeed plagiarism. Though rare, such cases do come to light from time to time, thanks in large part to the vigilance of our reviewers. Whether unintentional or otherwise, the practice is unacceptable, and contrary to journal policy. Therefore I should like to take this opportunity to remind authors (and reviewers) of their obligations, which are published in the author gui...

Validation of an accelerometer-based method to measure the use of manual wheelchairs—Editor's comment

Medical Engineering and Physics — Mon, 01 Apr 2013 04:00:00 +0100

The following correspondence, received in connection with the above article by Sonenblum et al. Med Eng Phys 2012; 34(6):781–6, created some cause for additional thought about the review and approach to manuscripts published in Medical Engineering & Physics. The quality of the science was not challenged, rather the proper attribution of credit to previous scientific contributions. (Source: Medical Engineering and Physics)

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