MedWorm: Biomedical Engineering

Editorial Board

Medical Engineering and Physics — Fri, 20 Nov 2009 16:27:21 +0100

(Source: Medical Engineering and Physics)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

IEEE Signal Processing Society Information

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

(Source: IEEE Transactions on Signal Processing)

2009 Index IEEE Transactions on Signal Processing Vol. 57

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing information for authors

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing Edics

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

(Source: IEEE Transactions on Signal Processing)

List of Reviewers

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

(Source: IEEE Transactions on Signal Processing)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Block-Wise Estimation of and Compensation for I/Q Imbalance in Direct-Conversion Transmitters

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

This correspondence proposes a new technique for accurate estimation and compensation for I/Q imbalance in modulators and demodulators used in direct-conversion radio transmitters. This technique uses the actual in-phase (I) and quadrature (Q) components of the modulated signals at the input and output of the transmitter-under-test for adaptive determination of the modulator and demodulator complex gain imbalances. The accuracy of the new algorithm is carefully assessed and compared to earlier works. The robustness of the algorithm to a number of common practical implementation issues (group delay, DC offset, propagation delay) are also discussed and demonstrated. (Source: IEEE Transactions on Signal Processing)

Robust IWFA for Open-Spectrum Communications

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

This correspondence considers a wireless open-spectrum communication system with $N$ orthogonal narrowband tones and $K$ users who compete to maximize their individual data rates. The correspondence proposes a robust version of the iterative water-filling algorithm (IWFA) that takes into account potential inaccuracies in the noise-plus-interference levels available at the transmitters. It is shown that, in comparison with the conventional version, the robust IWFA (RIWFA) can lead the users to behave in a less greedy fashion and to collaborate unintentionally in order to increase the network sum-rate. In particular, using an appropriately chosen RIWFA parameter, we show that RIWFA yields almost the same sum-rate as price-based IWFA (PIWFA) which requires collaboration of users. (Source: IEE...

Training Design for Repetitive-Slot-Based CFO Estimation in OFDM

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

Carrier frequency offset (CFO) estimation is a key challenge in wireless systems employing orthogonal frequency-division multiplexing (OFDM) modulation. Often, CFO estimation is carried out using a preamble made of a number, say $J$ , of repetitive slots (RS). We here focus on the issue of optimal RS preamble design using the CramÉr–Rao bound (CRB) averaged over the channel, which is assumed to be Rayleigh. We show that the optimal value of $J$ is a tradeoff between the multipath diversity gain and the number of unknowns to be estimated. In the case of correlated channel taps, we also show that uniform power loading of the active subcarriers is not optimal (in contrast with the uncorrelated case) and better power loading schemes are proposed. The proposed power loading scheme...

Blind Symbol Timing Estimation for OFDM/OQAM Systems

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

In this correspondence, we consider the problem of blind symbol timing (ST) estimation for pulse-shaping orthogonal frequency division multiplexing (OFDM) systems based on offset quadrature amplitude modulation (OQAM). In particular, under the assumption of low signal-to-noise ratio, the joint maximum-likelihood (ML) phase offset and ST estimator for additive white Gaussian noise (AWGN) channel is derived. Since the phase estimate is in closed form, the ST estimate requires a one-dimensional maximization procedure with respect to a continuous parameter. Specifically, the ST estimate depends on both the unconjugate and the conjugate correlation function of the transmitted OFDM/OQAM signal and exploits the cyclostationarity of the OFDM/OQAM signal that is related to the bandwidth of the cons...

Semiblind Bussgang Equalization for Sparse Channels

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

In this correspondence, we describe a semiblind Bussgang equalization scheme that incorporates the training sequence in a quite direct and flexible fashion. Among others, we discuss how the training sequence can be used to control the Bussgang nonlinearity thus enforcing the convergence of the iterative equalizer design. Moreover, we focus on the case of channels whose impulse response is long but sparse, counteracted by equalizers designed on a suitable sparse support. Numerical performance analysis conducted on compact and sparse time-varying channels shows that sparse Bussgang semiblind equalizer using a short training sequence outperforms blind, trained, and decision directed equalizers in a variety of fading conditions. (Source: IEEE Transactions on Signal Processing)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

On Low Complexity Robust Beamforming With Positive Semidefinite Constraints

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

This paper addresses the problem of robust beamforming for general-rank signal models with norm bounded uncertainties in the desired and received signal covariance matrices as well as positive semidefinite constraints on the covariance matrices. Two novel minimum variance robust beamformers are derived in closed-form. The first one basically is the closed-form version of an existing iterative algorithm, while the second one offers even better performance with respect to the first one. Both of them have the advantage of low complexity. The effectiveness and performance improvement of the proposed beamformers are verified by simulation results. (Source: IEEE Transactions on Signal Processing)

Design of Directional Filter Banks With Arbitrary Number of Subbands

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

This correspondence proposes a novel method for designing directional filter banks (DFBs) with arbitrary number of subbands. Its key feature is the ability to decompose images into arbitrary directionally oriented subbands. The proposed approach is based on the pseudo-polar Fourier transform (PPFT) and one-dimensional (1-D) filter banks (FBs). We take some modifications on the PPFT and then employ 1-D FBs to the modified PPFT. With these operations, the two-dimensional (2-D) DFBs are obtained and the design of them is converted to that of 1-D FBs plus a modified PPFT. Since the number of channels of 1-D FBs can be arbitrary, the 2-D DFBs with arbitrary number of subbands can be achieved which is highly expected for directional representations of images. Two examples on directional feature ...

Comment on “Parity-Check Matrix Calculation for Paraunitary Oversampled DFT Filter Banks”

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

In a previous paper, Karp, Kieffer, and Duhamel have presented three methods to calculate the parity-check matrix of paraunitary oversampled DFT filter banks. Here is another. (Source: IEEE Transactions on Signal Processing)

Widely Linear Estimation Algorithms for Second-Order Stationary Signals

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

Recursive estimation algorithms for discrete complex-valued second-order stationary signals are derived following a widely linear processing approach. The formulation is very general in that it allows for a variety of estimation problems. The results are applied on a simulation example and a performance analysis is presented. (Source: IEEE Transactions on Signal Processing)

Mobile Positioning Problem in Manhattan-Like Urban Areas: Uniqueness of Solution, Optimal Deployment of BSs, and Fuzzy Implementation

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

In this paper, the problem of mobile positioning in a Manhattan-like urban area is considered. For this area, the involved base stations (BSs) try to use the received distance data to position the mobile station (MS) of interest, which naturally leads to an algebraic problem. However, the concerned problem is analyzed from a geometrical point of view. Using this approach, it is found that the ability to uniquely determine the location of the MS by the knowledge of the positions of BSs and the received Manhattan distances is closely related to the positions of the MS and BSs. The uniqueness issue of mobile position is then discussed in detail, and the optimal deployment of BSs is proposed mathematically in the sense that the MS can be uniquely positioned most of the time. Under the optimal ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Error-Resilient Low-Power Viterbi Decoder Architectures

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

Three low-power Viterbi decoder (VD) architectures are presented in this paper. In the first, limited decision errors are introduced in the add-compare-select units (ACSUs) of a VD to reduce their critical path delays so that they can be operated at lower supply voltages without incurring timing errors. Power savings in this design can reach 58% and 44% with a 0.15 dB coding loss under reduced voltage operation and process variations, respectively, with adaptive supply voltage and adaptive body biasing applied to avoid timing errors. In the other two designs, we permit data-dependent timing errors to occur whenever a critical path in the ACSU is excited. Algorithmic noise-tolerance (ANT) is then applied to correct for these errors. Power reduction in these schemes is achieved by either ove...

Mapping Equivalence for Symbolic Sequences: Theory and Applications

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:38 +0100

We present strong and weak equivalence properties and rely on signal correlation to characterize equivalent mappings. We derive theoretical results which establish conditions for consistency among numerical mappings of symbolic data. Furthermore, we introduce an abstract mapping model for symbolic sequences and extend the notion of equivalence to an algebraic framework. Finally, we illustrate our theoretical results by application to DNA sequence analysis. (Source: IEEE Transactions on Signal Processing)

Efficient Batch and Adaptive Approximation Algorithms for Joint Multicast Beamforming and Admission Control

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

Wireless multicasting is becoming increasingly important for efficient distribution of streaming media and location-aware services to mobile and hand-held devices, network management, and software updates over cellular (UMTS-LTE) and indoor/outdoor wireless networks (e.g., 802.11/16). Multicast beamforming was recently proposed as a means of exploiting the broadcast nature of the wireless medium to boost spectral efficiency and meet Quality of Service (QoS) requirements. Infeasibility is a key issue in this context, due to power or mutual interference limitations. We therefore consider the joint multicast beamforming and admission control problem for one or more co-channel multicast groups, with the objective of maximizing the number of subscribers served and minimizing the power required ...

Robust Cognitive Beamforming With Bounded Channel Uncertainties

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

This paper studies the robust beamforming design for a multi-antenna cognitive radio (CR) network, which transmits to multiple secondary users (SUs) and coexists with a primary network of multiple users. We aim to maximize the minimum of the received signal-to-interference-plus-noise ratios (SINRs) of the SUs, subject to the constraints of the total SU transmit power and the received interference power at the primary users (PUs) by optimizing the beamforming vectors at the SU transmitter based on imperfect channel state information (CSI). To model the uncertainty in CSI, we consider a bounded region for both cases of channel matrices and channel covariance matrices. As such, the optimization is done while satisfying the interference constraints for all possible CSI error realizations. We s...

Finite Precision Analysis for Space-Time Decoding

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

Low complexity optimal (or nearly optimal) decoders for space-time codes have recently been under intensive investigation. For example, recent works by Sirianunpiboon and others show that the Silver code and the Golden code can be decoded optimally (or nearly optimally) with quadratic decoding complexity. Fast decodability makes them very attractive in practice. In implementing these decoders, floating-point to fixed-point conversion (FFC) needs to be carefully undertaken to minimize hardware cost while retaining decoding performance. The process of quantization for fixed-point representations is often ignored by research community and lacks investigation, and so FFC is often conducted heuristically based on simulations. This paper studies the effects of quantization to space-time coded sy...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

A Joint Source and Relay Power Allocation Scheme for a Class of MIMO Relay Systems

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

A joint power allocation (PA) scheme for a class of MIMO relay systems is presented in this paper. Based on the maximization of the capacity or minimization of the mean-square error (MSE), two joint PA optimization problems are first formulated. Since the cost functions thus obtained are in general not convex, a tight lower bound of the capacity and a similar upper bound of the MSE are derived, and employed to modify the two cost functions so as to obtain a convex optimization problem. It is confirmed through computer simulations that the proposed PA scheme outperforms the existing method in terms of both the capacity and the MSE of MIMO relay systems. (Source: IEEE Transactions on Signal Processing)

A Unified Framework for Optimizing Linear Nonregenerative Multicarrier MIMO Relay Communication Systems

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

In this paper, we develop a unified framework for linear nonregenerative multicarrier multiple-input multiple-output (MIMO) relay communications in the absence of the direct source–destination link. This unified framework classifies most commonly used design objectives such as the minimal mean-square error and the maximal mutual information into two categories: Schur-concave and Schur-convex functions. We prove that for Schur-concave objective functions, the optimal source precoding matrix and relay amplifying matrix jointly diagonalize the source–relay–destination channel matrix and convert the multicarrier MIMO relay channel into parallel single-input single-output (SISO) relay channels. While for Schur-convex objectives, such joint diagonalization occurs after a spe...

Correlation Matching Approach for Spectrum Sensing in Open Spectrum Communications

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

In this study, we propose three new procedures that are able to sense the known spectrum of the candidate or primary user, fulfilling the requirements of open spectrum scenarios. These procedures are developed by following the framework of correlation matching, changing the traditional single frequency scan to a spectral scan with a particular shape and generalizing filter-bank designs. The proposed techniques are called Candidate methods, because their goal is to react only when the candidate's spectral shape is present. First, Candidate-F is proposed as a spectral detection method, where this is based on minimizing the Frobenius distance between correlation matrices, and can be viewed as an extended version of the weighted overlapped spectrum averaging estimate. Next, Candidate-G is pres...

Efficient Implementation of Quasi- Maximum-Likelihood Detection Based on Semidefinite Relaxation

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

In this paper we develop two quasi-maximum likelihood (ML) channel detectors for multiuser detection: semidefinite relaxation (SDR) detector and phase-shift-keying (PSK) detector. These detectors can deliver near-ML bit error rate (BER) performance with a polynomial worst-case complexity. The SDR detector for binary-phase-shift-keying (BPSK) constellation is based on a convex SDR, whereas the PSK detector for $M$-PSK constellations is based on a nonconvex low-rank SDR. The SDR detector is implemented using a dual-scaling interior-point method, while the PSK detector is based on a coordinate descent strategy on a feasible region homotopy. We use dynamic dimension reduction and warm start techniques to achieve signal-to-noise ratio (SNR)-sensitive improvements for both detectors. Numerical s...

Parametric Dictionary Design for Sparse Coding

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:37 +0100

This paper introduces a new dictionary design method for sparse coding of a class of signals. It has been shown that one can sparsely approximate some natural signals using an overcomplete set of parametric functions. A problem in using these parametric dictionaries is how to choose the parameters. In practice, these parameters have been chosen by an expert or through a set of experiments. In the sparse approximation context, it has been shown that an incoherent dictionary is appropriate for the sparse approximation methods. In this paper, we first characterize the dictionary design problem, subject to a constraint on the dictionary. Then we briefly explain that equiangular tight frames have minimum coherence. The complexity of the problem does not allow it to be solved exactly. We introdu...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Minimum Bayes Risk Adaptive Linear Equalizers

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:34 +0100

This paper introduces Bayes risk (expected loss) as a criterion for linear equalization. Since the probability of error is equal to the Bayes risk (BR) for a particular binary loss function, this work is a natural generalization of previous works on minimum probability of error (PE) equalizers. Adaptive equalization algorithms are developed that minimize the BR. Like the minimum PE equalizers, the BR algorithms have low computational complexity which is comparable to that of the LMS algorithm. The advantage of the BR criterion is that the loss function can be specified in a manner that accelerates adaptive equalizer convergence relative to the minimum PE adaptive algorithm as illustrated in simulation examples. Besides introducing a new criterion, this paper provides another independent co...

Ranging Energy Optimization for Robust Sensor Positioning Based on Semidefinite Programming

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

Sensor positioning is an important task of location-aware wireless sensor networks. In most sensor positioning systems, sensors and beacons need to emit ranging signals to each other. Sensor ranging energy should be low to prolong system lifetime, but sufficiently high to fulfill prescribed accuracy requirements. This motivates us to investigate ranging energy optimization problems. We address ranging energy optimization for an unsynchronized positioning system, which features robust sensor positioning (RSP) in the sense that a specific accuracy requirement is fulfilled within a prescribed service area. We assume a line-of-sight (LOS) channel exists between the sensor and each beacon. The positioning is implemented by time-of-arrival (TOA) based two-way ranging between a sensor and beacons...

Information Theoretic Feature Extraction for Audio-Visual Speech Recognition

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

The problem of feature selection has been thoroughly analyzed in the context of pattern classification, with the purpose of avoiding the curse of dimensionality. However, in the context of multimodal signal processing, this problem has been studied less. Our approach to feature extraction is based on information theory, with an application on multimodal classification, in particular audio–visual speech recognition. Contrary to previous work in information theoretic feature selection applied to multimodal signals, our proposed methods penalize features for their redundancy, achieving more compact feature sets and better performance. We propose two greedy selection algorithms, one that penalizes a proportion of feature redundancy, while the other uses conditional mutual information as...

Adaptive Constrained Learning in Reproducing Kernel Hilbert Spaces: The Robust Beamforming Case

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

This paper establishes a new paradigm for convexly constrained adaptive learning in reproducing kernel Hilbert spaces (RKHS). Although the technique is of a general nature, we present it in the context of the beamforming problem. A priori knowledge, like beampattern specifications and constraints concerning robustness against steering vector errors, takes the form of multiple closed convex sets in a high (possibly infinite) dimensional RKHS. Every robustness constraint is shown to be equivalent to a min-max optimization task formed by means of the robust statistics $epsilon$ -insensitive loss function. Such a multiplicity of specifications turns out to obtain a simple expression by using the rich frame of fixed-point sets of certain mappings defined in a Hilbert space. Moreover, the cost f...

An Algorithm to Compute Averages on Matrix Lie Groups

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

Averaging is a common way to alleviate errors and random fluctuations in measurements and to smooth out data. Averaging also provides a way to merge structured data in a smooth manner. The present paper describes an algorithm to compute averages on matrix Lie groups. In particular, we discuss the case of averaging over the special orthogonal group of matrices, the unitary group of matrices and the group of symmetric positive-definite matrices. (Source: IEEE Transactions on Signal Processing)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Sequential Unfolding SVD for Tensors With Applications in Array Signal Processing

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

This paper contributes to the field of higher order $(N>2)$ tensor decompositions in signal processing. A novel PARATREE tensor model is introduced, accompanied with Sequential Unfolding SVD (SUSVD) algorithm. SUSVD, as the name indicates, applies a matrix singular value decomposition sequentially on the unfolded tensor reshaped from the right hand basis vectors of the SVD of the previous mode. The consequent PARATREE model is related to the well known family of PARAFAC tensor decomposition models. Both of them describe a tensor as a sum of rank-1 tensors, but PARATREE has several advantages over PARAFAC, when it is applied as a lower rank approximation technique. PARATREE is orthogonal (due to SUSVD), fast and reliable to compute, and the order (or rank) of the decomposition can be adapti...

Signal Reconstruction Errors in Jittered Sampling

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

One of the most significant types of error in digital signal processing (DSP) systems working with wideband signals is the error introduced by the analog-to-digital (AD) and digital-to-analog (DA) converters. This paper presents an accurate and simple method to evaluate the performance of AD/DA converters affected by clock jitter, which is based on the analysis of the mean square error (MSE) between the reconstructed signal and the original one. Using an approximation of the linear minimum MSE (LMMSE) filter as reconstruction technique, we derive analytic expressions of the MSE. In particular, through asymptotic analysis, we are able to simply evaluate the performance of digital signal reconstruction as a function of the clock jitter, number of quantization bits, signal bandwidth and sampl...

Complete Characterization of Stable Bandlimited Systems Under Quantization and Thresholding

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

In this paper, we analyze the approximation behavior of sampling series, where the sample values—taken equidistantly at Nyquist rate—are disturbed either by the nonlinear threshold operator or the nonlinear quantization operator. We perform the analysis for several spaces of bandlimited signals and completely characterize the spaces for which an approximation is possible. Additionally, we study the approximation of outputs of stable linear time-invariant systems by sampling series with disturbed samples for signals in ${cal PW}_{pi}^{1}$. We show that there exist stable systems that become unstable under thresholding and quantization and that the approximation error is unbounded irrespective of how small the quantization step size is chosen. Further, we give a necessary and s...

Recovering Sparse Signals With a Certain Family of Nonconvex Penalties and DC Programming

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

This paper considers the problem of recovering a sparse signal representation according to a signal dictionary. This problem could be formalized as a penalized least-squares problem in which sparsity is usually induced by a $ell _{1}$-norm penalty on the coefficients. Such an approach known as the Lasso or Basis Pursuit Denoising has been shown to perform reasonably well in some situations. However, it was also proved that nonconvex penalties like the pseudo $ell _{q}$-norm with $q≪ 1$ or smoothly clipped absolute deviation (SCAD) penalty are able to recover sparsity in a more efficient way than the Lasso. Several algorithms have been proposed for solving the resulting nonconvex least-squares problem. This paper proposes a generic algorithm to address such a sparsity recovery proble...

Generic Weighted Filtering of Stochastic Signals

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

In this paper, a new theory of optimal weighted nonlinear filtering is presented. Two filter models are considered. The first model is based on a representation of the filter in the polynomial-like form with $q$ terms where each term consists of weighted matrices and the matrix determined from the error minimization problem. The second model extends the first one to the case of the filter concatenation. The filter models are given in terms of pseudo-inverse matrices, i.e., the requirement of invertibility for covariance matrices is omitted. Thus, our filters always exist. We develop methods which allow us to exploit advantages associated with the proposed nonlinear filter models. The methods consist of the orthogonalization procedure and the reduction of the original problem to $q$ individ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Robust Reduced-Rank Adaptive Algorithm Based on Parallel Subgradient Projection and Krylov Subspace

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

In this paper, we propose a novel reduced-rank adaptive filtering algorithm exploiting the Krylov subspace associated with estimates of certain statistics of input and output signals. We point out that, when the estimated statistics are erroneous (e.g., due to sudden changes of environments), the existing Krylov-subspace-based reduced-rank methods compute the point that minimizes a “wrong” mean-square error (MSE) in the subspace. The proposed algorithm exploits the set-theoretic adaptive filtering framework for tracking efficiently the optimal point in the sense of minimizing the “true” MSE in the subspace. Therefore, compared with the existing methods, the proposed algorithm is more suited to adaptive filtering applications. A convergence analysis of the algori...

Vector Time-Frequency AR Models for Nonstationary Multivariate Random Processes

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

We introduce the vector time-frequency autoregressive (VTFAR) model for a parsimonious parametric description of nonstationary vector random processes. The VTFAR model generalizes the recently proposed scalar TFAR model to the multivariate case. It is physically meaningful because nonstationarity and spectral correlation are represented in terms of frequency shifts, and it is parsimonious for the practically relevant class of underspread vector processes (i.e., nonstationary vector processes with rapidly decaying correlation in time and frequency). For vector processes with decaying correlation across the signals, we introduce a variant of the VTFAR model with banded parameter matrices. Furthermore, we present a VTFAR parameter estimator that is based on a system of linear equations with t...

Sinusoidal Polynomial Parameter Estimation Using the Distribution Derivative

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:31 +0100

In this paper, we present a method to estimate the parameters of a generalized sinusoidal model. A generalized sinusoid $x$ is defined as a polynomial in the log domain, with complex coefficients $alpha_{i}$ : $x(t)=exp(sum_{i} alpha_{i} t^i)$, where $i=0cdots Q$. The method is based on the distribution derivative of the signal and operates in the transform domain. The method is very general and can use any linear transform such as the Fourier transform or the wavelet transform, or even combinations of linear transforms. Examples with the Fourier transform are given. The Fourier-based estimation methods are evaluated using synthetic signals and have performance very close to the theoretical bound. (Source: IEEE Transactions on Signal Processing)

A SURE Approach for Digital Signal/Image Deconvolution Problems

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:30 +0100

In this paper, we are interested in the classical problem of restoring data degraded by a convolution and the addition of a white Gaussian noise. The originality of the proposed approach is twofold. First, we formulate the restoration problem as a nonlinear estimation problem leading to the minimization of a criterion derived from Stein's unbiased quadratic risk estimate. Secondly, the deconvolution procedure is performed using any analysis and synthesis frames that can be overcomplete or not. New theoretical results concerning the calculation of the variance of the Stein's risk estimate are also provided in this work. Simulations carried out on natural images show the good performance of our method with respect to conventional wavelet-based restoration methods. (Source: IEEE Transactions ...

An Approximately Efficient TDOA Localization Algorithm in Closed-Form for Locating Multiple Disjoint Sources With Erroneous Sensor Positions

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:30 +0100

This paper considers the problem of time difference-of-arrival (TDOA) source localization when the TDOA measurements from multiple disjoint sources are subject to the same sensor position displacements from the available sensor positions. This is a challenging problem and closed-form solution with good localization accuracy has yet to be found. This paper proposes an estimator that can achieve this purpose. The proposed algorithm jointly estimates the unknown source and sensor positions to take the advantage that the TDOAs from different sources have the same sensor position displacements. The joint estimation is a highly nonlinear problem due to the coupling of source and sensor positions in the measurement equations. We introduce the novel idea of hypothesized source locations in the alg...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Free Electronic Access to SP Publications

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:30 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing publication information

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:30 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing — Thu, 19 Nov 2009 16:31:30 +0100

(Source: IEEE Transactions on Signal Processing)

Methods for Compensating for Variable Electrode Contact in EIT

IEEE Transactions on Biomedical Engineering — Thu, 19 Nov 2009 16:31:27 +0100

Electrical impedance tomography (EIT) is an imaging modality that currently shows promise for the detection and characterization of breast cancer. A very significant problem in EIT imaging is the proper modeling of the interface between the body and the electrodes. We have found empirically that it is very difficult, in a clinical setting, to assure that all electrodes make satisfactory contact with the body. In addition, we have observed a capacitive effect at the skin/electrode boundary that is spatially heterogeneous. To compensate for these problems, we have developed a hybrid nonlinear–linear reconstruction algorithm using the complete electrode model in which we first estimate electrode surface impedances, by means of a Levenberg–Marquardt iterative optimization procedu...

A Tissue Framework for Simulating the Effects of Gastric Electrical Stimulation and In Vivo Validation

IEEE Transactions on Biomedical Engineering — Thu, 19 Nov 2009 16:31:27 +0100

Gastric pacing is used to modulate normal or abnormal gastric slow-wave activity for therapeutic purposes. New protocols are required that are optimized for motility outcomes and energy efficiency. A computational tissue model was developed, incorporating smooth muscle and interstitial cell of Cajal layers, to enable predictive simulations of slow-wave entrainment efficacy under different pacing frequencies. Concurrent experimental validation was performed via high-resolution entrainment mapping in a porcine model (bipolar pacing protocol: 2 mA amplitude; 400 ms pulsewidth; 17-s period; midcorpus). Entrained gastric slow-wave activity was found to be anisotropic (circular direction: 8.51 mm${cdot}$s $^{-1}$; longitudinal: 4.58 mm${cdot}$s $^{-1}$), and the simulation velocities were specif...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

IEEE Transactions on Biomedical Engineering — Thu, 19 Nov 2009 16:31:27 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering publication information

IEEE Transactions on Biomedical Engineering — Thu, 19 Nov 2009 16:31:27 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering — Thu, 19 Nov 2009 16:31:27 +0100

(Source: IEEE Transactions on Biomedical Engineering)

Fabrication of monodisperse, large-sized, functional biopolymeric microspheres using a low-cost and facile microfluidic device.

Biomedical Microdevices — Thu, 19 Nov 2009 00:00:00 +0100

We report a novel and facile method for fabricating coaxial microfluidic devices processing various dimensions at low cost, in which polypropylene hollow fibers or glass capillaries are used as the tip of the dispersed phase injection tube. With this coaxial microfluidic device, monodisperse biocompatible microspheres ranging from 300 to 800 mum were obtained by collecting oil-in-water or water-in-oil emulsions and solidifying the suspended microspheres. Microsphere size could be controlled by changing the tips or tuning the concentrations of the dispersed and continuous phases. By adding functional nanoparticles into the dispersed phase, it was demonstrated that fluorescent and magnetic microspheres can be fabricated easily using these microfluidic devices. PMID: 19924539 [PubMed - as...

Identification of cultivation condition to produce correctly folded form of a malaria vaccine based on Plasmodium falciparum merozoite surface protein-1 in Escherichia coli.

Bioprocess and Biosystems Engineering — Wed, 18 Nov 2009 00:00:00 +0100

Authors: Mazumdar S, Sachdeva S, Chauhan VS, Yazdani SS The C-terminal, 19-kDa domain of Plasmodium falciparum merozoite surface protein-1 (PfMSP-1(19)) is among the leading vaccine candidate for malaria due to its essential role in erythrocyte invasion by the parasite. We designed a synthetic gene for optimal expression of recombinant PfMSP-1(19) in Escherichia coli and developed a scalable process to obtain high-quality PfMSP-1(19). The synthetic gene construct yielded a fourfold higher expression level of PfMSP-1(19) in comparison to the native gene construct. Optimization of cultivation conditions in the bioreactor indicated important role of yeast extract and substrate feeding strategy for obtaining enhanced expression of soluble and correctly folded PfMSP-1(19). It was observed t...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Study of age-related changes in postural control during quiet standing through Linear Discriminant Analysis

BioMedical Engineering OnLine — Wed, 18 Nov 2009 00:00:00 +0100

Conclusions: These results show that the analysis of features computed from the displacement of the COP are of great importance in studies trying to understand the ageing process. In particular, the LDA-value showed to be an adequate feature for assessment of changes in the postural control which can be related to functional changes that occur over the ageing. (Source: BioMedical Engineering OnLine)

Osteogenic Responses to Different Concentrations/Ratios of BMP-2 and bFGF in Bone Formation.

Annals of Biomedical Engineering — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Wang L, Huang Y, Pan K, Jiang X, Liu C Recombinant human bone morphogenetic protein-2 (rhBMP-2) and basic fibroblast growth factor (bFGF) are the focus of research pertaining to the stimulation of bone formation. We ascertained the effects of different concentrations rhBMP-2 on proliferation and differentiation of bone marrow stromal cells (BMSCs) in vitro and on ectopic bone formation in rats. BMSCs were obtained from beagle dogs and cultured in medium containing different concentrations rhBMP-2 and bFGF (0, 25, 50, 100, or 200 ng/mL). In a separate experiment, BMSCs were treated with different ratios (1:1, 2:1, 4:1, or 8:1) of rhBMP to bFGF (in each case the concentration of rhBMP was 100 ng/mL and the bFGF concentrations 100, 50, 25, or 12.5 ng/mL). Proliferation and differ...

Selection of Dynamic Features Based on Time-Frequency Representations for Heart Murmur Detection from Phonocardiographic Signals.

Annals of Biomedical Engineering — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Quiceno-Manrique AF, Godino-Llorente JI, Blanco-Velasco M, Castellanos-Dominguez G This work discusses a method for the selection of dynamic features, based on the calculation of the spectral power through time applied to the detection of systolic murmurs from phonocardiographic recordings. To investigate the dynamic properties of the spectral power during murmurs, several quadratic energy distributions have been studied, namely Wigner-Ville, Choi-Williams, smoothed pseudo Wigner-Ville, exponential, and hyperbolic T-distribution. The classification performance has been compared with that using a Short Time Fourier Transform and Continuous Wavelet Transform representations. Furthermore, this work discusses a variety of nonparametric techniques to estimate the spectral power con...

Micromechanical Characterization of Intra-luminal Thrombus Tissue from Abdominal Aortic Aneurysms.

Annals of Biomedical Engineering — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Gasser TC, Martufi G, Auer M, Folkesson M, Swedenborg J The reliable assessment of Abdominal Aortic Aneurysm rupture risk is critically important in reducing related mortality without unnecessarily increasing the rate of elective repair. Intra-luminal thrombus (ILT) has multiple biomechanical and biochemical impacts on the underlying aneurysm wall and thrombus failure might be linked to aneurysm rupture. Histological slices from 7 ILTs were analyzed using a sequence of automatic image processing and feature analyzing steps. Derived microstructural data was used to define Representative Volume Elements (RVE), which in turn allowed the estimation of microscopic material properties using the non-linear Finite Element Method. ILT tissue exhibited complex microstructural arrangemen...

Maintaining high anaerobic succinic acid productivity by product removal.

Bioprocess and Biosystems Engineering — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Andersson C, Petrova E, Berglund K, Rova U During dual-phase fermentations using Escherichia coli engineered for succinic acid production, the productivity and viable cell concentration decrease as the concentration of succinic acid increases. The effects of succinic acid on the fermentation kinetics, yield, and cell viability were investigated by resuspending cells in fresh media after selected fermentation times. The cellular succinic acid productivity could be restored, but cell viability continuously decreased throughout the fermentations by up to 80% and subsequently the volumetric productivity was reduced. Omitting complex nutrients in the resuspension media had no significant effect on cellular succinate productivity and yield, although the viable cell concentration and...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Endothelial cells influence the osteogenic potential of bone marrow stromal cells

BioMedical Engineering OnLine — Tue, 17 Nov 2009 00:00:00 +0100

Conclusion: These results show that co-culturing of EC and MSC for 5 days influences osteogenic differentiation of MSC, an effect that might be independent of Runx2, and enhances the production of ALP by MSC. (Source: BioMedical Engineering OnLine)

Process optimization for the production of diosgenin with Trichoderma reesei.

Bioprocess and Biosystems Engineering — Sun, 15 Nov 2009 00:00:00 +0100

Authors: Zhu Y, Ni J, Huang W Based on the response surface methodology, an effective microbial system for diosgenin production from enzymatic pretreated Dioscorea zingiberensis tubers with Trichoderma reesei was studied. The fermentation medium was optimized with central composite design (3(5)) depended on Plackett-Burmann design which identified significant impacts of peptone, K(2)HPO(4) and Tween 80 on diosgenin yield. The effects of different fermentation conditions on diosgenin production were also studied. Four parameters, i.e. incubation period, temperature, initial pH and substrate concentration were optimized using 4(5) central composite design. The highest diosgenin yield of 90.57% was achieved with 2.67% (w/v) of peptone, 0.29% (w/v) of K(2)HPO(4), 0.73% (w/v) of Tween 80 an...

Estimating the cellular maintenance coefficient and its use in the design of two-phase partitioning bioscrubbers.

Bioprocess and Biosystems Engineering — Sat, 14 Nov 2009 00:00:00 +0100

Authors: Yeom SH, Daugulis AJ, Nielsen DR One of the key roles of an organic solvent has emerged to be the enhancement of oxygen transfer in two-phase partitioning bioscrubbers (TPPBs). In order to determine an optimum organic fraction for a given VOCs loading, the oxygen demand of the total cell mass must be estimated, which depends upon the magnitude of the cellular maintenance coefficient. We have estimated the dynamics of the maintenance coefficient for benzene degradation by Achromobacter xylosoxidans Y234 in a TPPB and found that the maintenance coefficient generally decreased as cells accumulated in the TPPB but converged to a specific value of 1.750 x 10(-2) h(-1) at biological steady state. Due to its important influence on all of the essential design parameters of the TPPB sy...

Nonlinear process modeling of fructosyltransferase (FTase) using bootstrap re-sampling neural network model.

Bioprocess and Biosystems Engineering — Sat, 14 Nov 2009 00:00:00 +0100

Authors: Ahmad Z, Mat Don M, Mortan SH, Mat Noor RA Recently, the increased demand of fructooligosaccharides (FOS) as a functional food has alarmed researchers to screen and identify new strains capable of producing fructosyltransferase (FTase). FTase is the enzyme that converts the substrate (sucrose) to glucose and fructose. The characterization of complex sugar such as table sugar, brown sugar, molasses, etc. will be carried out and the sugar that contained the highest sucrose concentration will be selected as a substrate. Eight species of macro-fungi will be screened for its ability to produce FTase and only one strain with the highest FTase activity will be selected for further studies. In this work, neural networks (NN) have been chosen to model the process based on their excelle...

The Glenohumeral Capsule Should be Evaluated as a Sheet of Fibrous Tissue: A Validated Finite Element Model.

Annals of Biomedical Engineering — Fri, 13 Nov 2009 00:00:00 +0100

The objective of this work was to validate the predicted strain distribution and deformed shape of the inferior glenohumeral ligament using experimental data for two subject-specific finite element models: (1) a continuous model including all capsular regions, and (2) a discrete model including only the inferior glenohumeral ligament. The distribution of maximum principal strain and deformed shape of the glenohumeral capsule was determined for a cadaveric shoulder in a joint position frequently associated with dislocation (60 degrees of glenohumeral abduction, 52 degrees of external rotation, and a 25 N anterior load applied to the humerus). The experimental kinematics were then applied to the two finite element models constructed from the geometry and material properties from the same cad...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Rheological Study of Synovial Fluid Obtained from Dogs: Healthy, Pathological, and Post-Surgery, after Spontaneous Rupture of Cranial Cruciate Ligament.

Annals of Biomedical Engineering — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Goudoulas TB, Kastrinakis EG, Nychas SG, Papazoglou LG, Kazakos GM, Kosmas PV In the present study synovial fluid (SF) obtained from the stifle joint of healthy adult dogs and of dogs after cranial cruciate ligament rupture was analyzed regarding its rheological characteristics according to the condition of the joint. The viscoelastic and shear flow properties were measured at 25 and 38 degrees C. The results showed that the healthy SF exhibits practically temperature independent viscosity curve and satisfactory viscoelastic characteristics, i.e. G' > G'', over frequencies of 0.05-5 Hz, and characteristic relaxation time lambda of the order of magnitude of 100 s. Creep measurements demonstrate that the zero shear viscosity was in the range of 10-100 Pa s. In shear flow visc...

Biomedical engineering and bibliometric indices for scientific quality

Medical and Biological Engineering and Computing — Thu, 12 Nov 2009 18:41:09 +0100

Content Type Journal ArticleCategory EditorialDOI 10.1007/s11517-009-0546-9Authors Jos A. E. Spaan, University of Amsterdam Department Biomedical Engineering and Physics, Academic Medical Center Amsterdam The Netherlands Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)

First in vivo assessment of “Outwalk”: a novel protocol for clinical gait analysis based on inertial and magnetic sensors

Medical and Biological Engineering and Computing — Thu, 12 Nov 2009 18:41:07 +0100

Abstract A protocol named “Outwalk” was recently proposed to measure the thorax–pelvis and lower-limb kinematics during gait in free-living conditions, by means of an inertial and magnetic measurement system (IMMS). The aim of this study was to validate Outwalk on four healthy subjects when it is used in combination with a specific IMMS (Xsens Technologies, NL), against a reference protocol (CAST) and measurement system (optoelectronic system; Vicon, Oxford Metrics Group, UK). For this purpose, we developed an original approach based on three tests, which allowed to separately investigate: (1) the consequences on joint kinematics of the differences between protocols (Outwalk vs. CAST), (2) the accuracy of the hardware (Xsens vs. Vicon), and (3) the summation of proto...

‘Outwalk’: a protocol for clinical gait analysis based on inertial and magnetic sensors

Medical and Biological Engineering and Computing — Thu, 12 Nov 2009 18:41:05 +0100

Abstract A protocol named Outwalk was developed to easily measure the thorax–pelvis and lower-limb 3D kinematics on children with cerebral palsy (CP) and amputees during gait in free-living conditions, by means of an Inertial and Magnetic Measurement System (IMMS). Outwalk defines the anatomical/functional coordinate systems (CS) for each body segment through three steps: (1) positioning the sensing units (SUs) of the IMMS on the subjects’ thorax, pelvis, thighs, shanks and feet, following simple rules; (2) computing the orientation of the mean flexion–extension axis of the knees; (3) measuring the SUs’ orientation while the subject’s body is oriented in a predefined posture, either upright or supine. If the supine posture is chosen, e.g. when spasticity does not...

Stopping mechanism for capsule endoscope using electrical stimulus

Medical and Biological Engineering and Computing — Thu, 12 Nov 2009 18:41:02 +0100

Abstract An ingestible capsule, which has the ability to stop at certain locations in the small intestine, was designed and implemented to monitor intestinal diseases. The proposed capsule can contract the small intestine by using electrical stimuli; this contraction causes the capsule to stop when the maximum static frictional force (MSFF) is larger than the force of natural peristalsis. In vitro experiments were carried out to verify the feasibility of the capsule, and the results showed that the capsule was successfully stopped in the small intestine. Various electrodes and electrical stimulus parameters were determined on the basis of the MSFF. A moderate increment of the MSFF (12.7 ± 4.6 gf at 5 V, 10 Hz, and 5 ms) and the maximum in...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Electroencephalographic spectral asymmetry index for detection of depression

Medical and Biological Engineering and Computing — Thu, 12 Nov 2009 18:40:51 +0100

This study is aimed to compare sensitivity of different electroencephalographic (EEG) indicators for detection of depression. The novel EEG spectral asymmetry index (SASI) was introduced based on balance between the powers of two special EEG frequency bands selected lower and higher of the EEG spectrum maximum and excluding the central frequency from the calculations. The efficiency of the SASI was compared to the traditional EEG inter-hemispheric asymmetry and coherence methods. EEG recordings were carried out on groups of depressive and healthy subjects of 18 female volunteers each. The resting eight-channel EEG was recorded during 30 min. The SASI calculated in an arbitrary EEG channel differentiated clearly between the depressive and healthy group (p < 0.005). C...

Three Dimensional Active Contours for the Reconstruction of Abdominal Aortic Aneurysms.

Annals of Biomedical Engineering — Tue, 10 Nov 2009 00:00:00 +0100

In this study, we describe a technique to reconstruct AAA geometry from CT images in an inexpensive and streamlined fashion. A 3D reconstruction technique was implemented with a GUI interface in MATLAB using the active contours technique. The lumen and the thrombus of the AAA were segmented individually in two separate protocols and were then joined together into a hybrid surface. This surface was then used to obtain the aortic wall. This method can deal with very poor contrast images where the aortic wall is indistinguishable from the surrounding features. Data obtained from the segmentation of image sets were smoothed in 3D using a Support Vector Machine technique. The segmentation method presented in this paper is inexpensive and has minimal user-dependency in reconstructing AAA geometr...

Kinetics of enzymatic trans-esterification of glycerides for biodiesel production.

Bioprocess and Biosystems Engineering — Tue, 10 Nov 2009 00:00:00 +0100

Authors: Calabrò V, Ricca E, De Paola MG, Curcio S, Iorio G In this paper, the reaction of enzymatic trans-esterification of glycerides with ethanol in a reaction medium containing hexane at a temperature of 37 degrees C has been studied. The enzyme was Lipase from Mucor miehei, immobilized on ionic exchange resin, aimed at achieving high catalytic specific surface and recovering, regenerating and reusing the biocatalyst. A kinetic analysis has been carried out to identify the reaction path; the rate equation and kinetic parameters have been also calculated. The kinetic model has been validated by comparison between predicted and experimental results. Mass transport resistances estimation was undertaken in order to verify that the kinetics found was intrinsic. Model potentialities...

Composition of the pericellular matrix modulates the deformation behaviour of chondrocytes in articular cartilage under static loading

Medical and Biological Engineering and Computing — Sat, 07 Nov 2009 07:49:25 +0100

Abstract The aim was to assess the role of the composition changes in the pericellular matrix (PCM) for the chondrocyte deformation. For that, a three-dimensional finite element model with depth-dependent collagen density, fluid fraction, fixed charge density and collagen architecture, including parallel planes representing the split-lines, was created to model the extracellular matrix (ECM). The PCM was constructed similarly as the ECM, but the collagen fibrils were oriented parallel to the chondrocyte surfaces. The chondrocytes were modelled as poroelastic with swelling properties. Deformation behaviour of the cells was studied under 15% static compression. Due to the depth-dependent structure and composition of cartilage, axial cell strains were highly depth-dependent. ...

A Novel Simulation Strategy for Stent Insertion and Deployment in Curved Coronary Bifurcations: Comparison of Three Drug-Eluting Stents.

Annals of Biomedical Engineering — Sat, 07 Nov 2009 00:00:00 +0100

This study investigates and compares three different second generation DESs when being implanted in the curved main branch of a coronary bifurcation with the aim of providing better insights into the related changes of the mechanical environment. The 3D bifurcation model is based on patient-specific angiographic data that accurately reproduce the in vivo curvatures of the vessel segments. The layered structure of the arterial wall and its anisotropic mechanical behavior are taken into account by applying a novel algorithm to define the fiber orientations. An innovative simulation strategy considering the insertion of a folded balloon catheter over a guide wire is proposed in order to position the stents within the curved vessel. Straightening occurs after implantation of all stents investi...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Print-and-Peel Fabrication for Microfluidics: What's in it for Biomedical Applications?

Annals of Biomedical Engineering — Sat, 07 Nov 2009 00:00:00 +0100

This article reviews the development and the advances of print-and-peel (PAP) microfabrication. PAP techniques provide means for facile and expedient prototyping of microfluidic devices. Therefore, PAP has the potential for broadening the microfluidics technology by bringing it to researchers who lack regular or any accesses to specialized fabrication facilities and equipment. Microfluidics have, indeed, proven to be an indispensable toolkit for biological and biomedical research and development. Through accessibility to such methodologies for relatively fast and easy prototyping, PAP has the potential to considerably accelerate the impacts of microfluidics on the biological sciences and engineering. In summary, PAP encompasses: (1) direct printing of the masters for casting polymer device...

Computer-assisted quantification of lung tumors in respiratory gated PET/CT images: phantom study

Medical and Biological Engineering and Computing — Thu, 05 Nov 2009 18:58:01 +0100

Abstract A computer-aided method was developed to automatically localize tumors in lung PET images of discrete bins within the breathing cycle, followed by an algorithm that registers all the information of a complete respiratory cycle into a single reference bin. Four registration/integration algorithms: Centroid Based, Intensity Based, Rigid Body, and Optical Flow registration were compared as well as two registration schemes: Direct scheme and Successive scheme. Validation was demonstrated by conducting experiments with the computerized 4D NCAT phantom and with a dynamic lung–chest phantom imaged using a GE PET/CT System. Iterations were conducted on different size simulated tumors. Static tumors without respiratory motion were used as gold standard; quantitative resu...

Investigation of Pulsatile Flowfield in Healthy Thoracic Aorta Models.

Annals of Biomedical Engineering — Thu, 05 Nov 2009 00:00:00 +0100

Authors: Wen CY, Yang AS, Tseng LY, Chai JW Cardiovascular disease is the primary cause of morbidity and mortality in the western world. Complex hemodynamics plays a critical role in the development of aortic dissection and atherosclerosis, as well as many other diseases. Since fundamental fluid mechanics are important for the understanding of the blood flow in the cardiovascular circulatory system of the human body aspects, a joint experimental and numerical study was conducted in this study to determine the distributions of wall shear stress and pressure and oscillatory WSS index, and to examine their correlation with the aortic disorders, especially dissection. Experimentally, the Phase-Contrast Magnetic Resonance Imaging (PC-MRI) method was used to acquire the true geometry of a no...

14th Nordtrib Conference - Abstract submission deadline postponed to 9 Nov 2009

Elsevier Updates: Engineering — Thu, 05 Nov 2009 00:00:00 +0100

Storforsen, Northern Sweden, 8 - 11th June 2010. Arranged by Luleå University of Technology. Abstract submission deadline postponed to November 9th. (Source: Elsevier Updates: Engineering)

Theoretical evaluation of a simple cooling pad for inducing hypothermia in the spinal cord following traumatic injury

Medical and Biological Engineering and Computing — Wed, 04 Nov 2009 20:00:38 +0100

Abstract The Pennes bioheat equation and finite element method (FEM) are used to solve for the temperature distributions in the spinal cord and cerebrospinal fluid (CSF) during 30 min of cooling for spinal cord injury (SCI) patients. The average CSF and spinal cord temperatures are reduced by 3.48 and 2.72°C, respectively. The 100-mm wide pad provides the desired cooling and uses the least amount of material. The presence of zero-average CSF oscillation under normal conditions decreases the cooling extent in the spinal cord due to the introduction of warm CSF surrounding the spinal cord. The temperature decrease in the spinal cord is more than doubled when the temperature at the back of the torso is lowered from 20 to 0°C. Spinal cord ischemia, often observed after ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Unsupervised movement onset detection from EEG recorded during self-paced real hand movement

Medical and Biological Engineering and Computing — Wed, 04 Nov 2009 06:59:22 +0100

This article presents an unsupervised method for movement onset detection from electroencephalography (EEG) signals recorded during self-paced real hand movement. A Gaussian Mixture Model (GMM) is used to model the movement and idle-related EEG data. The GMM built along with appropriate classification and post processing methods are used to detect movement onsets using self-paced EEG signals recorded from five subjects, achieving True–False rate difference between 63 and 98%. The results show significant performance enhancement using the proposed unsupervised method, both in the sample-by-sample classification accuracy and the event-by-event performance, in comparison with the state-of-the-art supervised methods. The effectiveness of the proposed method suggests its potential appli...

Effectiveness of thigh-to-thigh current path for the measurement of abdominal fat in bioelectrical impedance analysis

Medical and Biological Engineering and Computing — Wed, 04 Nov 2009 06:59:19 +0100

We present a new method measuring body impedance using a thigh-to-thigh current path, which can reflect the abdominal fat portion more sensitively and can be conveniently applied during the daily use on a toilet seat. Two pairs of electrodes were installed on a toilet seat to provide current and to permit voltage measurement through a thigh-to-thigh current path. The effectiveness of the method was compared with conventional foot-to-foot and hand-to-foot current paths by simulation and by experiments referenced to computed tomography (CT) image analysis. Body impedance using three different current paths was measured, and abdominal CT images were acquired for eight subjects. Measured body impedances were compared with the visceral to subcutaneous fat ratio (VF/SF) calculated from the...

International Conference on Fatigue Damage of Structural Materials VIII - Abstract submission deadline 07 December 2009

Elsevier Updates: Engineering — Wed, 04 Nov 2009 00:00:00 +0100

The 8th biennial Fatigue Damage of Structural Materials conference will be held in Cape Cod at The Resort and Conference Center at Hyannis, MA, 19-24 Sept 2010. Visit the conference website for a list of topics. Abstract submission deadline 07 Dec 2009. (Source: Elsevier Updates: Engineering)

Fourth International Conference on Engineering Failure Analysis - Abstract Submission Deadline 27 Nov

Elsevier Updates: Engineering — Wed, 04 Nov 2009 00:00:00 +0100

Elsevier will host the 4th International Conference on Engineering Failure Analysis at Churchill College, Cambridge, UK, in July 2010. Visit the conference website for the list of topics. Abstract submission deadline: 27 Nov 2009 (Source: Elsevier Updates: Engineering)

Batch and fed-batch fermentation of Bacillus thuringiensis using starch industry wastewater as fermentation substrate.

Bioprocess and Biosystems Engineering — Wed, 04 Nov 2009 00:00:00 +0100

Authors: Vu KD, Tyagi RD, Valéro JR, Surampalli RY Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch fermentation with two intermittent feeds (at 10 and 20 h) during the fermentation of 72 h gave the maximum delta-endotoxin concentration (1,672.6 mg/L) and entomotoxicity (Tx) (18.5 x 10(6) SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0 mg/L) and Tx (15.8 x 10(6) SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34 h) of the fermentation resulted in the formation of asporogenous variant (Spo-) from 36 h to the end of fermentation (72 h) which re...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Enzymatic synthesis of poly-L: -lactide and poly-L: -lactide-co-glycolide in an ionic liquid.

Bioprocess and Biosystems Engineering — Wed, 04 Nov 2009 00:00:00 +0100

Authors: Chanfreau S, Mena M, Porras-Domínguez JR, Ramírez-Gilly M, Gimeno M, Roquero P, Tecante A, Bárzana E The syntheses of poly-L: -lactide (PLLA) and poly-L: -lactide-co-glycolide (PLLGA) is reported in the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF(6)] mediated by the enzyme lipase B from Candida antarctica (Novozyme 435). The highest PLLA yield (63%) was attained at 90 degrees C with a molecular weight (M ( n )) of 37.8 x 10(3) g/mol determined by size exclusion chromatography. This procedure produced relatively high crystalline polymers (up to 85% PLLA) as determined by DSC. In experiments at 90 degrees C product synthesis also occurred without biocatalyst, however, PLLA synthesis in [HMIM][PF(6)] at 65 degrees C followed only the enzy...

International Conference on Fatigue Damage of Structural Materials VIII - Abstract submission deadline 07 December 2009

Elsevier Updates: Engineering — Wed, 04 Nov 2009 00:00:00 +0100

Fourth International Conference on Engineering Failure Analysis - Abstract Submission Deadline 27 Nov

Elsevier Updates: Engineering — Wed, 04 Nov 2009 00:00:00 +0100

Enzymatic digestion of articular cartilage results in viscoelasticity changes that are consistent with polymer dynamics mechanisms

BioMedical Engineering OnLine — Wed, 04 Nov 2009 00:00:00 +0100

Conclusions: These results demonstrate that enzymatic digestion alters cartilage viscoelastic properties in a manner consistent with polymer dynamics mechanisms. Future studies may expand the use of polymer dynamics as a microstructural model for understanding the contributions of specific matrix molecules toward tissue-level viscoelastic properties. (Source: BioMedical Engineering OnLine)

Cement mantle stress under retroversion torque at heel-strike

Medical Engineering and Physics — Mon, 02 Nov 2009 00:00:00 +0100

Abstract: The paper presents a theory of fixation failure and loosening in cemented total hip prostheses and proceeds to investigate this using an experimentally validated finite element model and two prosthesis types, namely the Charnley and the C-Stem. The study investigates the effects of retroversion torque occurring at heel-strike in combination with a loss of proximal cement/bone support and distal implant/cement support with a good distal cement/bone interface. A 3D finite element model was validated by comparison of femoral surface strains with those measured in an in vitro experimental simulation using an implanted Sawbone femur loaded in the heel-strike position and including a simplified representation of muscle forces. Results showed that the heel-strike position applies a high...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Editorial Board

Medical Engineering and Physics — Sun, 01 Nov 2009 00:00:00 +0100

(Source: Medical Engineering and Physics)

Improvement of laccase production and its properties by low-energy ion implantation.

Bioprocess and Biosystems Engineering — Sat, 31 Oct 2009 00:00:00 +0100

Authors: Liu Z, Zhang D, Hua Z, Li J, Du G, Chen J Low-energy ion implantation was employed to breed laccase producing strain Paecilomyces sp. WSH-L07 and a mutant S152 that exhibited an activity of more than three times over the wild strain was obtained. The optimum substrate of both the wild and mutant laccases was 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate), and followed by guaiacol with optimal pH at 3.4 and 5.0, respectively, while the mutant laccase exhibited a broader active pH range. The mutant laccase had a higher optimal catalytic temperature (60-65 degrees C) than the wild one (55 degrees C), and the wild laccase deactivated rapidly when temperature increased above 55 degrees C. Furthermore, the mutant laccase was more stable under neutral and alkaline conditions. A t...

IEEE Transactions on Medical Imaging information for authors

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

(Source: IEE Transactions on Medical Imaging)

Explore IEL IEEE's most comprehensive resource

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

(Source: IEE Transactions on Medical Imaging)

Special issue on multivariate microscopy image analysis

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

(Source: IEE Transactions on Medical Imaging)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Isbi 2010

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

(Source: IEE Transactions on Medical Imaging)

Correction for Susceptibility-Induced Distortion in Echo-Planar Imaging Using Field Maps and Model-Based Point Spread Function

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

In conclusion, the proposed framework gave us an overall picture of how different correction methods work. The model-based PSF method, which required fewer reference scans and less computational load, was more clinically feasible than other methods. (Source: IEE Transactions on Medical Imaging)

Cardiac C-Arm CT: A Unified Framework for Motion Estimation and Dynamic CT

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

Generating 3-D images of the heart during interventional procedures is a significant challenge. In addition to real time fluoroscopy, angiographic C-arm systems can also now be used to generate 3-D/4-D CT images on the same system. One protocol for cardiac CT uses ECG triggered multisweep scans. A 3-D volume of the heart at a particular cardiac phase is then reconstructed by applying Feldkamp (FDK) reconstruction to the projection images with retrospective ECG gating. In this work we introduce a unified framework for heart motion estimation and dynamic cone-beam reconstruction using motion corrections. The benefits of motion correction are 1) increased temporal and spatial resolution by removing cardiac motion which may still exist in the ECG gated data sets and 2) increased signal-to-nois...

Kernel Granger Causality Mapping Effective Connectivity on fMRI Data

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:01 +0100

Although it is accepted that linear Granger causality can reveal effective connectivity in functional magnetic resonance imaging (fMRI), the issue of detecting nonlinear connectivity has hitherto not been considered. In this paper, we address kernel Granger causality (KGC) to describe effective connectivity in simulation studies and real fMRI data of a motor imagery task. Based on the theory of reproducing kernel Hilbert spaces, KGC performs linear Granger causality in the feature space of suitable kernel functions, assuming an arbitrary degree of nonlinearity. Our results demonstrate that KGC captures effective couplings not revealed by the linear case. In addition, effective connectivity networks between the supplementary motor area (SMA) as the seed and other brain areas are obtained fr...

Robust Initial Detection of Landmarks in Film-Screen Mammograms Using Multiple FFDM Atlases

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Automated analysis of mammograms requires robust methods for pectoralis segmentation and nipple detection. Locating the nipple is especially important in multiview computer aided detection systems, in which findings are matched across images using the nipple-to-finding distance. Segmenting the pectoralis is a key preprocessing step to avoid false positives when detecting masses due to the similarity of the texture of mammographic parenchyma and the pectoral muscle. A multiatlas algorithm capable of providing very robust initial estimates of the nipple position and pectoral region in digitized mammograms is presented here. Ten full-field digital mammograms, which are easily annotated attributed to their excellent contrast, are robustly registered to the target digitized film-screen mammogra...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Rapid Dynamic Image Registration of the Beating Heart for Diagnosis and Surgical Navigation

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Dynamic cardiac magnetic resonance imaging (MR) and computed tomography (CT) provide cardiologists and cardiac surgeons with high-quality 4-D images for diagnosis and therapy, yet the effective use of these high-quality anatomical models remains a challenge. Ultrasound (US) is a flexible imaging tool, but the US images produced are often difficult to interpret unless they are placed within their proper 3-D anatomical context. The ability to correlate real-time 3-D US volumes (RT3D US) with dynamic MR/CT images would offer a significant contribution to improve the quality of cardiac procedures. In this paper, we present a rapid two-step method for registering RT3D US to high-quality dynamic 3-D MR/CT images of the beating heart. This technique overcomes some major limitations of image regis...

Distribution of Fiducial Registration Error in Rigid-Body Point-Based Registration

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Rigid-body point-based registration is frequently used in computer assisted surgery to align corresponding points, or fiducials, in preoperative and intraoperative data. This alignment is mostly achieved by assuming the same homogeneous error distribution for all the points; however, due to the properties of the medical instruments used in measuring the point coordinates, the error distribution might be inhomogeneous and different for each point. In this paper, in an effort to understand the effect of error distribution in the localized points on the performed registration, we derive a closed-form solution relating the error distribution of each point with the performed registration accuracy. The solution uses maximum likelihood estimation to calculate the probability density function of r...

Effects of Different Imaging Models on Least-Squares Image Reconstruction Accuracy in Photoacoustic Tomography

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

In the classic formulation of photoacoustic tomography (PAT), two distinct descriptions of the imaging model have been employed for developing reconstruction algorithms. We demonstrate that the numerical and statistical properties of unweighted least-squares reconstruction algorithms associated with each imaging model are generally very different. Specifically, some PAT reconstruction algorithms, including many of the iterative algorithms previously explored, do not work directly with the raw measured pressure wavefields, but rather with an integrated data function that is obtained by temporally integrating the photoacoustic wavefield. The integration modifies the statistical distribution of the data, introducing statistical correlations among samples. This change is highly significant for...

${K}$ -Space and Image-Space Combination for Motion-Induced Phase-Error Correction in Self-Navigated Multicoil Multishot DWI

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Motion during diffusion encodings leads to different phase errors in different shots of multishot diffusion-weighted acquisitions. Phase error incoherence among shots results in undesired signal cancellation when data from all shots are combined. Motion-induced phase error correction for multishot diffusion-weighted imaging (DWI) has been studied extensively and there exist multiple phase error correction algorithms. A commonly used correction method is the direct phase subtraction (DPS). DPS, however, can suffer from incomplete phase error correction due to the aliasing of the phase errors in the high spatial resolution phases. Furthermore, improper sampling density compensation is also a possible issue of DPS. Recently, motion-induced phase error correction was incorporated in the conjug...

Model-Based Iterative Reconstruction for Radial Fast Spin-Echo MRI

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

In radial fast spin-echo magnetic resonance imaging (MRI), a set of overlapping spokes with an inconsistent T2 weighting is acquired, which results in an averaged image contrast when employing conventional image reconstruction techniques. This work demonstrates that the problem may be overcome with the use of a dedicated reconstruction method that further allows for T2 quantification by extracting the embedded relaxation information. Thus, the proposed reconstruction method directly yields a spin-density and relaxivity map from only a single radial data set. The method is based on an inverse formulation of the problem and involves a modeling of the received MRI signal. Because the solution is found by numerical optimization, the approach exploits all data acquired. Further, it handles mult...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Effect of Voxel Size and Computation Method on Tc-99m MAA SPECT/CT-Based Dose Estimation for Y-90 Microsphere Therapy

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

The use of selective internal radiation therapy for treatment of hepatocellular carcinoma and liver metastases using Y-90 labeled microspheres has become an effective and widely used treatment regimen. However, dosimetric evaluations of this treatment are still primitive as uniform distribution models based only on injected activity are often used. This investigation attempts to quantify the effectiveness of several sophisticated patient-specific techniques which utilize the source distribution of Tc-99m MAA simulation studies to perform voxelized dosimetric computations. Among these techniques are complete Monte-Carlo radiation transport computation in patient-specific CT-based voxel phantoms, local energy deposition in patient specific phantoms and kernel transport techniques in water. E...

A New Distortion Model for Strong Inhomogeneity Problems in Echo-Planar MRI

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

This paper proposes a new distortion model for strong inhomogeneity problems in echo planar imaging (EPI). Fast imaging sequences in magnetic resonance imaging (MRI), such as EPI, are very important in applications where temporal resolution or short total acquisition time is essential. Unfortunately, fast imaging sequences are very sensitive to variations in the homogeneity of the main magnetic field. The inhomogeneity leads to geometrical distortions and intensity changes in the image reconstructed via fast Fourier transform. Also, under strong inhomogeneity, the accelerated intravoxel dephase may overly attenuate signals coming from regions with higher inhomogeneity variations. Moreover, coarse discretization schemes for the inhomogeneity are not able to cope with this problem, producing...

A Reconstruction Algorithm for Photoacoustic Imaging Based on the Nonuniform FFT

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Fourier reconstruction algorithms significantly outperform conventional backprojection algorithms in terms of computation time. In photoacoustic imaging, these methods require interpolation in the Fourier space domain, which creates artifacts in reconstructed images. We propose a novel reconstruction algorithm that applies the one-dimensional nonuniform fast Fourier transform to photoacoustic imaging. It is shown theoretically and numerically that our algorithm avoids artifacts while preserving the computational effectiveness of Fourier reconstruction. (Source: IEE Transactions on Medical Imaging)

Generalized Algorithms for Direct Reconstruction of Parametric Images From Dynamic PET Data

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Indirect and direct methods have been developed for reconstructing parametric images from dynamic positron emission tomography (PET) data. Indirect methods are simple and easy to implement because reconstruction and kinetic modeling are performed in two separate steps. Direct methods estimate parametric images directly from dynamic PET sinograms and, in theory, can be statistically more efficient, but the algorithms are often difficult to implement and are very specific to the kinetic model being used. This paper presents a class of generalized algorithms for direct reconstruction of parametric images that are relatively easy to implement and can be adapted to different kinetic models. The proposed algorithms use optimization transfer principle to convert the maximization of a penalized li...

A Stochastic Approach to Estimate the UncertaintyInvolved in B-Spline Image Registration

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Uncertainties in image registration may be a significant source of errors in anatomy mapping as well as dose accumulation in radiotherapy. It is, therefore, essential to validate the accuracy of image registration. Here, we propose a method to detect areas where mono modal B-spline registration performs well and to distinguish those from areas of the same image, where the registration is likely to be less accurate. It is a stochastic approach to automatically estimate the uncertainty of the resulting displacement vector field. The coefficients resulting from the B-spline registration are subject to moderate and randomly performed variations. A quantity is proposed to characterize the local sensitivity of the similarity measure to these variations. We demonstrate the statistical dependence ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

An Image Based Auto-Focusing Algorithm forDigital Fundus Photography

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpness of an image. The AF algorithm was tested in the prototype of a semi-automated nonmydriatic fundus camera designed to screen in the primary care environment for major eye diseases. A series of images was acquired in volunteers while focusing the camera on the fundus. The image with the best focus was determined by the AF algorithm and compared to the assessment of two masked readers. A set of fu...

Statistical Sinogram Restoration in Dual-Energy CT for PET Attenuation Correction

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

We report simulations that compare the proposed techniques and existing approaches. (Source: IEE Transactions on Medical Imaging)

In Vivo High-ResolutionConductivity Imaging of the Human Leg Using MREIT: The First Human Experiment

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

We present the first in vivo cross-sectional conductivity image of the human leg with 1.7 mm pixel size using the magnetic resonance electrical impedance tomography (MREIT) technique. After a review of its experimental protocol by an Institutional Review Board (IRB), we performed MREIT imaging experiments of four human subjects using a 3 T MRI scanner. Adopting thin and flexible carbon–hydrogel electrodes with a large surface area and good contact, we could inject as much as 9 mA current in a form of 15 ms pulse into the leg without producing a painful sensation and motion artifact. Sequentially injecting two imaging currents in two different directions, we collected induced magnetic flux density data inside the leg. Scaled conductivity images reconstructed by using the single-step ...

Approaching Artery Rigid Dynamics in IVUS

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

Tissue biomechanical properties (like strain and stress) are playing an increasing role in diagnosis and long-term treatment of intravascular coronary diseases. Their assessment strongly relies on estimation of vessel wall deformation. Since intravascular ultrasound (IVUS) sequences allow visualizing vessel morphology and reflect its dynamics, this technique represents a useful tool for evaluation of tissue mechanical properties. Image misalignment introduced by vessel–catheter motion is a major artifact for a proper tracking of tissue deformation. In this work, we focus on compensating and assessing IVUS rigid in-plane motion due to heart beating. Motion parameters are computed by considering both the vessel geometry and its appearance in the image. Continuum mechanics laws serve t...

B-Mode Ultrasound Image Simulation in Deformable 3-D Medium

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

This paper presents an algorithm for fast image synthesis inside deformed volumes. Given the node displacements of a mesh and a reference 3-D image dataset of a predeformed volume, the method first maps the image pixels that need to be synthesized from the deformed configuration to the nominal predeformed configuration, where the pixel intensities are obtained easily through interpolation in the regular-grid structure of the reference voxel volume. This mapping requires the identification of the mesh element enclosing each pixel for every image frame. To accelerate this point location operation, a fast method of projecting the deformed mesh on image pixels is introduced in this paper. The method presented was implemented for ultrasound B-mode image simulation of a synthetic tissue phantom....

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

IEEE Transactions on Medical Imaging publication information

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

(Source: IEE Transactions on Medical Imaging)

IEE Transactions on Medical Imaging — Fri, 30 Oct 2009 16:21:00 +0100

(Source: IEE Transactions on Medical Imaging)

Blank page

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering information for authors

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

(Source: IEEE Transactions on Biomedical Engineering)

Quality without compromise

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

(Source: IEEE Transactions on Biomedical Engineering)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Intervertebral Disc Segmentation and Volumetric Reconstruction From Peripheral Quantitative Computed Tomography Imaging

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

An automatic system for segmenting and constructing volumetric representations of excised intervertebral discs from peripheral quantitative computed tomography (PQCT) imagery is presented. The system is designed to allow for automatic quantitative analysis of progressive herniation damage to the intervertebral discs under flexion/extension motions combined with a compressive load. Automatic segmentation and volumetric reconstruction of intervertebral disc from PQCT imagery is a very challenging problem due to factors such as streak artifacts and unclear material density separation between contrasted intervertebral disc and surrounding bone in the PQCT imagery, as well as the formation of multiple contrasted regions under axial scans. To address these factors, a novel multiscale level set a...

Non-invasive Wet Electrocochleography

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

To detect electrocochleographic (ECochG) potentials generated by the cochlea in response to auditory stimuli, either transtympanic or tympanic/extratympanic electrodes are currently used. The first are invasive, while the second are arranged in contact or very close to the tympanic membrane (TM). To avoid the discomfort and the risks inherent to the application of such conventional electrodes, this Letter presents an alternative technique. A conducting liquid is inserted into the ear canal to act as a distributed electrical interface between the TM and an external electrode. Thus, ECochG potentials are detected without any direct contact between the solid electrode and the sensitive TM. This technique was tested on ten volunteers with single-click auditory stimuli. Results showed its effic...

A Novel Concept for a Prosthetic Hand With a Bidirectional Interface: A Feasibility Study

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

A conceptually novel prosthesis consisting of a mechatronic hand, an electromyographic classifier, and a tactile display has been developed and evaluated by addressing problems related to controllability in prosthetics: intention extraction, perception, and feeling of ownership. Experiments have been performed, and encouraging results for a young transradial amputee are reported. (Source: IEEE Transactions on Biomedical Engineering)

A Novel Criterion of Wavelet Packet Best Basis Selection for Signal Classification With Application to Brain–Computer Interfaces

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

This study proposes a method to select a wavelet basis for classification. It uses a strategy defined by Wickerhauser and Coifman and proposes a new additive criterion describing the contrast between classes. Its performance is compared with other approaches on simulated signals and on experimental EEG signals for brain–computer interface applications. (Source: IEEE Transactions on Biomedical Engineering)

A New Discriminative Common Spatial Pattern Method for Motor Imagery Brain–Computer Interfaces

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Event-related desynchronization/synchronization patterns during right/left motor imagery (MI) are effective features for an electroencephalogram-based brain–computer interface (BCI). As MI tasks are subject-specific, selection of subject-specific discriminative frequency components play a vital role in distinguishing these patterns. This paper proposes a new discriminative filter bank (FB) common spatial pattern algorithm to extract subject-specific FB for MI classification. The proposed method enhances the classification accuracy in BCI competition III dataset IVa and competition IV dataset IIb. Compared to the performance offered by the existing FB-based method, the proposed algorithm offers error rate reductions of 17.42% and 8.9% for BCI competition datasets III an...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Detection of Discontinuous Patterns in Spontaneous Brain Activity of Neonates and Fetuses

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

The discontinuous patterns in neonatal magnetoencephalographic (MEG) data are quantified with a novel Hilbert phase (HP) based approach. The expert neurologists’ scores were used as the gold standard. The performance of this approach was analyzed using a receiver operating characteristic (ROC) curve, and it was compared with two other approaches, namely spectral ratio (SR) and discrete wavelet transform (DWT) that have been proposed for the detection of discontinuous patterns in neonatal EEG. The area under the ROC curve (AUC) was used as a performance measure. AUCs obtained for SR, HP, and DWT were 0.87, 0.80, and 0.56, respectively. Although the performance of HP was lower than SR, it carries information about the frequency content of the signal that helps to distinguish brain pat...

Early Cortical Connective Network Relating to Audiovisual Stimulation by Partial Directed Coherence Analysis

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Cross-modal sensory integration between the auditory and visual systems has long been a topic of interest in cognitive neuroscience, but spatiotemporal cortical interdependence under audiovisual stimulation is still poorly understood. In this letter, parametric spectral analysis, specifically partial directed coherence (PDC), is used to study the cortical connective causal-interdependence network under audiovisual cognitive processes within the time window of the N1 component, i.e., 96--145 ms poststimulus in the event-related potential (ERP). A total of 13 subjects (age: $22.9pm 0.8$ years; male/female = $9/4$) performed an audiovisual recognition task. Multichannel EEG signals were analyzed using an adaptive multivariate autoregressive model to identify causal influences between d...

Analysis of the Mechanism of Action of Deep Brain Stimulation Using the Concepts of Dither Injection and the Equivalent Nonlinearity

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Deep brain stimulation (DBS) is a widely applied clinical procedure for the alleviation of pathological neural activity, and is particularly effective in suppressing the symptoms of Parkinson's disease. The mechanisms of action of DBS remain to be fully elucidated. In this paper, we present an application to DBS of the concepts of dither injection and equivalent nonlinearity from the theory of nonlinear feedback control systems. We propose that this model provides a framework for understanding the mechanism by which an injected high-frequency signal can quench undesired oscillations in closed-loop systems of interacting neurons in the brain. (Source: IEEE Transactions on Biomedical Engineering)

Multiple Types of Movement-Related Information Encoded in Hindlimb/Trunk Cortex in Rats and Potentially Available for Brain–Machine Interface Controls

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Brain–machine interface (BMI) systems hold the potential to return lost functions to patients with motor disorders. To date, most efforts in BMI have concentrated on decoding neural activity from forearm areas of cortex to operate a robotic arm or perform other manipulation tasks. Efforts have neglected the locomotion functions of hindlimb/trunk cortex. However, the role of cortex in hindlimb locomotion of intact rats, which are often model systems for BMI testing, is usually considered to be small. Thus, the quality of representations of locomotion available in this area was uncertain. We designed a new rodent BMI system, and tested decoding of the kinematics of trunk and hindlimbs during locomotion using linear regression. Recordings were made from the motor cortex of the hindlimb...

Combinatory Electrical and Pharmacological Neuroprosthetic Interfaces to Regain Motor Function After Spinal Cord Injury

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Severe lesions of the rodent or human spinal cord lead to permanent paralysis of the legs. Here, we review novel evidences suggesting that interventions combining pharmacological and electrical stimulations of the spinal cord have a high potential to promote the recovery of locomotion following severe spinal cord injuries in humans. These strategies are based on the existence of webs of circuits and receptors embedded in the spinal motor infrastructure that each modulate specific aspects of locomotor movements. We show that chemical or electrical stimulations can engage specific elements of this spinal machinery, thus resulting in distinct patterns of locomotion in paralyzed spinal rats. In turn, simultaneous chemical stimulations of neural receptors and/or electrical stimulations of multi...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

An Implantable Microactuated Intrafascicular Electrode for Peripheral Nerves

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:55 +0100

Important advancements have been recently achieved in the field of neural interfaces to restore lost sensory and motor functions. The aim of this letter was to develop an innovative approach to increase the selectivity and the lifetime of polyimide-based intrafascicular electrodes. The main idea was to obtain a neural interface that is able to restore a good signal quality by improving the electrical connection between the active sites and the surrounding axons. The high flexibility of polyimide-based neural interfaces allows to embed microactuators in the interface core and achieve desired microdisplacements of the active sites. Nearly equiatomic nickel–titanium alloy was selected as a microactuator because of its shape memory effect. A single TiNi thin film was obtained by dc magn...

Toward Energy Efficient Neural Interfaces

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

This letter presents progress toward an energy efficient neural data acquisition transponder for brain–computer interfaces. The transponder utilizes a four-channel time-multiplexed analog front-end and an energy efficient short-range backscattering RF link to transmit digitized wireless data. In addition, a low-complexity autonomous and adaptive digital neural signal processor is proposed to minimize wireless bandwidth and overall power dissipation. (Source: IEEE Transactions on Biomedical Engineering)

Directional PC12 Cell Migration Along Plastic Nanotracks

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

The design of materials to promote the development and/or regeneration of neuronal tissue requires the understanding of the mechanisms by which the underlying substrate topography can modulate neuronal cell differentiation and migration. We recently demonstrated that plastic nanogratings (alternating lines of grooves and ridges of submicrometer size) can effectively change the neuronal polarity state, selecting bipolar cells with aligned neurites. Here, we address the effect of nanogratings on the migration properties of differentiating PC12 cells and correlate their behavior with the polarity state induced by the substrate. During neuronal differentiation, cell–substrate interaction is sufficient to induce directional migration along the nanogratings. Control cells contacting flat ...

Guest Editorial to the Special Letters Issue on Neuroengineering and Neuroprosthetics: Increasing Basic Understanding of the Nervous System to Develop More Effective Neuroengineering Applications

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

Reviewers

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Introducing TBME Letters Special Issue on Neuroengineering and Neuroprosthetics

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering publication information

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering — Fri, 30 Oct 2009 16:20:54 +0100

(Source: IEEE Transactions on Biomedical Engineering)

A method to estimate EMG crosstalk between two muscles based on the silent period following an H-reflex

Medical Engineering and Physics — Fri, 30 Oct 2009 00:00:00 +0100

Abstract: The crosstalk phenomenon consists in recording the volume-conducted electromyographic activity of muscles other than that under study. This interference may impair the correct interpretation of the results in a variety of experiments. A new protocol is presented here for crosstalk assessment between two muscles based on changes in their electrical activity following a reflex discharge in one of the muscles in response to nerve stimulation. A reflex compound muscle action potential (H-reflex) was used to induce a silent period in the muscle that causes the crosstalk, called here the remote muscle. The rationale is that if the activity recorded in the target muscle is influenced by a distant source (the remote muscle) a silent period observed in the electromyogram (EMG) of the remo...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

A System for Recording High Fidelity Cough Sound and Airflow Characteristics.

Annals of Biomedical Engineering — Fri, 30 Oct 2009 00:00:00 +0100

The objective of this study was to develop a system to measure high fidelity voluntary cough sounds to detect lung diseases. To further augment the analysis capability of the system, a non-invasive flow measurement was also incorporated into the design. One of the main design considerations was to increase the fidelity of the recorded sound characteristics by increasing the signal to noise ratio of cough sounds and to minimize acoustical reflections from the environment. To accomplish this goal, a system was designed with a mouthpiece connected to a cylindrical tube. A microphone was attached near the mouthpiece so that its diaphragm was tangent to the inner surface of the cylinder. A pneumotach at the end of the tube measured the airflow generated by the cough. The system was terminated w...

Purkinje-mediated Effects in the Response of Quiescent Ventricles to Defibrillation Shocks.

Annals of Biomedical Engineering — Fri, 30 Oct 2009 00:00:00 +0100

This study uses a computer modeling approach to assess contributions by the PS to the response to electrical stimulation. Normal sinus rhythm was simulated and epicardial breakthrough sites were distributed in a manner consistent with experimental results. Defibrillation shocks of several strengths and orientations were applied to quiescent ventricles, with and without PS, and electrical activation was analyzed. All shocks induced local polarizations in PS branches parallel to the field, which led to the rapid spread of excitation through the network. This produced early activations at myocardial sites where tissue was unexcited by the shock and coupled to the PS. Shocks along the apico-basal axis of the heart resulted in a significant abbreviation of activation time when the PS was presen...

Geometry of the Intervertebral Volume and Vertebral Endplates of the Human Spine.

Annals of Biomedical Engineering — Fri, 30 Oct 2009 00:00:00 +0100

In this study, existing CT-scans of 77 patients were analyzed to measure the intervertebral disc and vertebral endplate geometry of the lumbar spine. Ten adjacent points on both sides of the vertebrae (S1-superior to T12-inferior) and sagittal and transverse diameters were measured to describe the shape of the caudal and cranial vertebral planes of the vertebrae. It was found that the largest endplate depth is located in the middle or posterior regions of the vertebra, that there is a linear relationship between all inferior endplate depths and the endplate location (p < 0.0001) within the spinal column, and that the superior endplate depth increases with age by about 0.01 mm per year (p < 0.02). The wedge angle increases from T12-L1 to L5-S1. The results allow for improvement of the...

Anaerobic treatment of winery wastewater in fixed bed reactors.

Bioprocess and Biosystems Engineering — Fri, 30 Oct 2009 00:00:00 +0100

Authors: Ganesh R, Rajinikanth R, Thanikal JV, Ramanujam RA, Torrijos M The treatment of winery wastewater in three upflow anaerobic fixed-bed reactors (S9, S30 and S40) with low density floating supports of varying size and specific surface area was investigated. A maximum OLR of 42 g/l day with 80 +/- 0.5% removal efficiency was attained in S9, which had supports with the highest specific surface area. It was found that the efficiency of the reactors increased with decrease in size and increase in specific surface area of the support media. Total biomass accumulation in the reactors was also found to vary as a function of specific surface area and size of the support medium. The Stover-Kincannon kinetic model predicted satisfactorily the performance of the reactors. The maximum remov...

Electronic Submission now available for CIRP - Journal of Manufacturing Science and Technology

Elsevier Updates: Engineering — Thu, 29 Oct 2009 00:00:00 +0100

Electronic submission is now available for CIRP - Journal of Manufacturing Science and Technology. Authors interested in submitting an article should visit http://ees.elsevier.com/cirpj/ (Source: Elsevier Updates: Engineering)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Electronic Submission now available for CIRP - Journal of Manufacturing Science and Technology

Elsevier Updates: Engineering — Thu, 29 Oct 2009 00:00:00 +0100

Editorial.

Annals of Biomedical Engineering — Wed, 28 Oct 2009 00:00:00 +0100

Authors: McIntire LV PMID: 19862616 [PubMed - as supplied by publisher] (Source: Annals of Biomedical Engineering)

Mathematical Modeling of Flow-Generated Forces in an In Vitro System of Cardiac Valve Development.

Annals of Biomedical Engineering — Wed, 28 Oct 2009 00:00:00 +0100

Authors: Biechler SV, Potts JD, Yost MJ, Junor L, Goodwin RL, Weidner JW Heart valve defects are the most common cardiac defects. Therefore, defining the mechanisms of cardiac valve development is critical to our understanding and treatment of these disorders. At early stages of embryonic cardiac development, the heart begins as a simple tube that then becomes constricted into separate atrial and ventricular regions by the formation of small, mound-like structures, called atrioventricular (AV) cushions. As valve development continues, these mounds fuse and then elongate into valve leaflets. A longstanding hypothesis proposes that blood flow-generated shear stress and pressure are critical in shaping the cushions into leaflets. Here we show results from a two-dimensional mathematical mo...

The development of 3-D, in vitro, endothelial culture models for the study of coronary artery disease

BioMedical Engineering OnLine — Wed, 28 Oct 2009 00:00:00 +0100

The response of the vascular endothelium to wall shear stress plays a central role in the development and progression of atherosclerosis. Current studies have investigated endothelial response using idealized in vitro flow chambers. Such cell culture models are unable to accurately replicate the complex in vivo wall shear stress patterns arising from anatomical geometries. To better understand this implication, we have created both simplified/tubular and anatomically realistic in vitro endothelial flow models of the human right coronary artery. A post-mortem vascular cast of the human left ventricular outflow tract was used to create geometrically accurate silicone elastomer models. Straight, tubular models were created using a custom made mold. Following the culture of human abdominal aor...

Robust algorithm for arrhythmia classification in ECG using extreme learning machine

BioMedical Engineering OnLine — Wed, 28 Oct 2009 00:00:00 +0100

Conclusions: The proposed algorithm shows effective accuracy performance with a short learning time. In addition we ascertained the robustness of the proposed algorithm by evaluating the entire MIT-BIH arrhythmia database. (Source: BioMedical Engineering OnLine)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Classification of BMI control commands from rat's neural signals using extreme learning machine

BioMedical Engineering OnLine — Wed, 28 Oct 2009 00:00:00 +0100

A recently developed machine learning algorithm referred to as Extreme Learning Machine (ELM) was used to classify machine control commands out of time series of spike trains of ensembles of CA1 hippocampus neurons (n = 34) of a rat, which was performing a target-to-goal task on a two-dimensional space through a brain-machine interface system. Performance of ELM was analyzed in terms of training time and classification accuracy. The results showed that some processes such as class code prefix, redundancy code suffix and smoothing effect of the classifiers' outputs could improve the accuracy of classification of robot control commands for a brain-machine interface system. (Source: BioMedical Engineering OnLine)

New Editor for Engineering Failure Analysis

Elsevier Updates: Engineering — Tue, 27 Oct 2009 00:00:00 +0100

As of 1 September 2009, Richard Clegg replaced Dai Jones as Editor-in-Chief. Richard Clegg is Professor of Industrial Material Science at Central Queensland University, Australia (Source: Elsevier Updates: Engineering)

Changes in the Mechanical Properties and Residual Strain of Elastic Tissue in the Developing Fetal Aorta.

Annals of Biomedical Engineering — Tue, 27 Oct 2009 00:00:00 +0100

Authors: Wells SM, Walter EJ Formed almost exclusively during development, arterial elastic fibers must function for the lifetime of the animal. We have observed dramatic structural and mechanical changes in aortic elastic tissue during gestational and postnatal development. Elastic tissue was isolated from bovine aortas: (i) during late pregnancy and (ii) in adults. Changes in the relative content of aortic elastic tissue were assessed, as were the viscoelastic properties and residual strains of purified aortic elastic tissue rings. As aortic elastic tissue content increased during development, its circumference and thickness increased-but with circumference rising faster than wall thickness, causing a relative thinning of the elastic tissue. At the same time, elastic tissue stiffness...

Mesh Morphing and Response Surface Analysis: Quantifying Sensitivity of Vertebral Mechanical Behavior.

Annals of Biomedical Engineering — Tue, 27 Oct 2009 00:00:00 +0100

Authors: Sigal IA, Whyne CM Vertebrae provide essential biomechanical stability to the skeleton. In this work novel morphing techniques were used to parameterize three aspects of the geometry of a specimen-specific finite element (FE) model of a rat caudal vertebra (process size, neck size, and end-plate offset). Material properties and loading were also parameterized using standard techniques. These parameterizations were then integrated within an RSM framework and used to produce a family of FE models. The mechanical behavior of each model was characterized by predictions of stress and strain. A metamodel was fit to each of the responses to yield the relative influences of the factors and their interactions. The direction of loading, offset, and neck size had the largest influences o...

MedWorm: Biomedical Engineering

Editorial Board

IEEE Signal Processing Society Information

2009 Index IEEE Transactions on Signal Processing Vol. 57

IEEE Transactions on Signal Processing information for authors

IEEE Transactions on Signal Processing Edics

List of Reviewers

Block-Wise Estimation of and Compensation for I/Q Imbalance in Direct-Conversion Transmitters

Robust IWFA for Open-Spectrum Communications

Training Design for Repetitive-Slot-Based CFO Estimation in OFDM

Blind Symbol Timing Estimation for OFDM/OQAM Systems

Semiblind Bussgang Equalization for Sparse Channels

On Low Complexity Robust Beamforming With Positive Semidefinite Constraints

Design of Directional Filter Banks With Arbitrary Number of Subbands

Comment on “Parity-Check Matrix Calculation for Paraunitary Oversampled DFT Filter Banks”

Widely Linear Estimation Algorithms for Second-Order Stationary Signals

Mobile Positioning Problem in Manhattan-Like Urban Areas: Uniqueness of Solution, Optimal Deployment of BSs, and Fuzzy Implementation

Error-Resilient Low-Power Viterbi Decoder Architectures

Mapping Equivalence for Symbolic Sequences: Theory and Applications

Efficient Batch and Adaptive Approximation Algorithms for Joint Multicast Beamforming and Admission Control

Robust Cognitive Beamforming With Bounded Channel Uncertainties

Finite Precision Analysis for Space-Time Decoding

A Joint Source and Relay Power Allocation Scheme for a Class of MIMO Relay Systems

A Unified Framework for Optimizing Linear Nonregenerative Multicarrier MIMO Relay Communication Systems

Correlation Matching Approach for Spectrum Sensing in Open Spectrum Communications

Efficient Implementation of Quasi- Maximum-Likelihood Detection Based on Semidefinite Relaxation

Parametric Dictionary Design for Sparse Coding

Minimum Bayes Risk Adaptive Linear Equalizers

Ranging Energy Optimization for Robust Sensor Positioning Based on Semidefinite Programming

Information Theoretic Feature Extraction for Audio-Visual Speech Recognition

Adaptive Constrained Learning in Reproducing Kernel Hilbert Spaces: The Robust Beamforming Case

An Algorithm to Compute Averages on Matrix Lie Groups

Sequential Unfolding SVD for Tensors With Applications in Array Signal Processing

Signal Reconstruction Errors in Jittered Sampling

Complete Characterization of Stable Bandlimited Systems Under Quantization and Thresholding

Recovering Sparse Signals With a Certain Family of Nonconvex Penalties and DC Programming

Generic Weighted Filtering of Stochastic Signals

Robust Reduced-Rank Adaptive Algorithm Based on Parallel Subgradient Projection and Krylov Subspace

Vector Time-Frequency AR Models for Nonstationary Multivariate Random Processes

Sinusoidal Polynomial Parameter Estimation Using the Distribution Derivative

A SURE Approach for Digital Signal/Image Deconvolution Problems

An Approximately Efficient TDOA Localization Algorithm in Closed-Form for Locating Multiple Disjoint Sources With Erroneous Sensor Positions

Free Electronic Access to SP Publications

IEEE Transactions on Signal Processing publication information

Table of contents

Methods for Compensating for Variable Electrode Contact in EIT

A Tissue Framework for Simulating the Effects of Gastric Electrical Stimulation and In Vivo Validation

Table of Contents

IEEE Transactions on Biomedical Engineering publication information

Table of Contents

Fabrication of monodisperse, large-sized, functional biopolymeric microspheres using a low-cost and facile microfluidic device.

Identification of cultivation condition to produce correctly folded form of a malaria vaccine based on Plasmodium falciparum merozoite surface protein-1 in Escherichia coli.

Study of age-related changes in postural control during quiet standing through Linear Discriminant Analysis

Osteogenic Responses to Different Concentrations/Ratios of BMP-2 and bFGF in Bone Formation.

Selection of Dynamic Features Based on Time-Frequency Representations for Heart Murmur Detection from Phonocardiographic Signals.

Micromechanical Characterization of Intra-luminal Thrombus Tissue from Abdominal Aortic Aneurysms.

Maintaining high anaerobic succinic acid productivity by product removal.

Endothelial cells influence the osteogenic potential of bone marrow stromal cells

Process optimization for the production of diosgenin with Trichoderma reesei.

Estimating the cellular maintenance coefficient and its use in the design of two-phase partitioning bioscrubbers.

Nonlinear process modeling of fructosyltransferase (FTase) using bootstrap re-sampling neural network model.

The Glenohumeral Capsule Should be Evaluated as a Sheet of Fibrous Tissue: A Validated Finite Element Model.

Rheological Study of Synovial Fluid Obtained from Dogs: Healthy, Pathological, and Post-Surgery, after Spontaneous Rupture of Cranial Cruciate Ligament.

Biomedical engineering and bibliometric indices for scientific quality

First in vivo assessment of “Outwalk”: a novel protocol for clinical gait analysis based on inertial and magnetic sensors

‘Outwalk’: a protocol for clinical gait analysis based on inertial and magnetic sensors

Stopping mechanism for capsule endoscope using electrical stimulus

Electroencephalographic spectral asymmetry index for detection of depression

Three Dimensional Active Contours for the Reconstruction of Abdominal Aortic Aneurysms.

Kinetics of enzymatic trans-esterification of glycerides for biodiesel production.

Composition of the pericellular matrix modulates the deformation behaviour of chondrocytes in articular cartilage under static loading

A Novel Simulation Strategy for Stent Insertion and Deployment in Curved Coronary Bifurcations: Comparison of Three Drug-Eluting Stents.

Print-and-Peel Fabrication for Microfluidics: What's in it for Biomedical Applications?

Computer-assisted quantification of lung tumors in respiratory gated PET/CT images: phantom study

Investigation of Pulsatile Flowfield in Healthy Thoracic Aorta Models.

14th Nordtrib Conference - Abstract submission deadline postponed to 9 Nov 2009

Theoretical evaluation of a simple cooling pad for inducing hypothermia in the spinal cord following traumatic injury

Unsupervised movement onset detection from EEG recorded during self-paced real hand movement

Effectiveness of thigh-to-thigh current path for the measurement of abdominal fat in bioelectrical impedance analysis

International Conference on Fatigue Damage of Structural Materials VIII - Abstract submission deadline 07 December 2009