Biomedical Engineering Research 
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This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 27.
Generating Stochastic Gene Regulatory Networks Consistent With Pathway Information and Steady-State Behavior
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We present a procedure to generate a stochastic genetic regulatory network model consistent with pathway information. Using the stochastic dynamics of Markov chains, we produce a model constrained by the prior knowledge despite the sometimes incomplete, time independent, and often conflicting nature of these pathways. We apply the Markov theory to study the model’s long run behavior and introduce a biologically important transformation to aid in comparison with real biological outcome prediction in the steady-state domain. Our technique produces biologically faithful models without the need for rate kinetics, detail...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Real-Time Automatic Tuning of Noise Suppression Algorithms for Cochlear Implant ApplicationsEmail this article to a colleague.
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The performance of cochlear implants deteriorates in noisy environments compared to quiet conditions. This paper presents an adaptive cochlear implant system, which is capable of classifying the background noise environment in real time for the purpose of adjusting or tuning its noise suppression algorithm to that environment. The tuning is done automatically with no user intervention. Five objective quality measures are used to show the superiority of this adaptive system compared to a conventional fixed noise-suppression system. Steps taken to achieve the real-time implementation of the entire system, incorporating both ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Multilevel Segmentation of Histopathological Images Using Cooccurrence of Tissue ObjectsEmail this article to a colleague.
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This paper presents a new approach for unsupervised segmentation of histopathological tissue images. This approach has two main contributions. First, it introduces a new set of high-level texture features to represent the prior knowledge of spatial organization of the tissue components. These texture features are defined on the tissue components, which are approximately represented by tissue objects, and quantify the frequency of two component types being cooccurred in a particular spatial relationship. As they are defined on components, rather than on image pixels, these object cooccurrence features are expected to be les...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Surface Mosaics of the Bladder Reconstructed From Endoscopic Video for Automated SurveillanceEmail this article to a colleague.
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Flexible cystoscopy is frequently performed for recurrent bladder cancer surveillance, making it the most expensive cancer to treat over the patient's lifetime. An automated bladder surveillance system is being developed to robotically scan the bladder surface using an ultrathin and highly flexible endoscope. Such a system would allow cystoscopic procedures to be overseen by technical staff while urologists could review cystoscopic video postoperatively. In this paper, we demonstrate a method for reconstructing the surface of the whole bladder from endoscopic video using structure from motion. Video is acquired from...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Enhancing the Accuracy of Subcutaneous Glucose Sensors: A Real-Time Deconvolution-Based ApproachEmail this article to a colleague.
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In this study, we design and test a real-time signal-enhancement module that, cascaded to the CGM device, improves the quality of its output by a proper postprocessing of the CGM signal. In fact, CGM sensors measure glucose in the interstitium rather than in the blood compartment. We show that this distortion can be compensated by means of a regularized deconvolution procedure relying on a linear regression model that can be updated whenever a pair of suitably sampled SMBG references is collected. Tests performed both on simulated and real data demonstrate a significant accuracy improvement of the CGM signal. Simulation st...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
High-Density Myoelectric Pattern Recognition Toward Improved Stroke RehabilitationEmail this article to a colleague.
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Myoelectric pattern-recognition techniques have been developed to infer user's intention of performing different functional movements. Thus electromyogram (EMG) can be used as control signals of assisted devices for people with disabilities. Pattern-recognition-based myoelectric control systems have rarely been designed for stroke survivors. Aiming at developing such a system for improved stroke rehabilitation, this study assessed detection of the affected limb's movement intention using high-density surface EMG recording and pattern-recognition techniques. Surface EMG signals comprised of 89 channels were re...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Time-Based Compression and Classification of HeartbeatsEmail this article to a colleague.
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Heart function measured by electrocardiograms (ECG) is crucial for patient care. ECG generated waveforms are used to find patterns of irregularities in cardiac cycles in patients. In many cases, irregularities evolve over an extended period of time that requires continuous monitoring. However, this requires wireless ECG recording devices. These devices consist of an enclosed system that includes electrodes, processing circuitry, and a wireless communication block imposing constraints on area, power, bandwidth, and resolution. In order to provide continuous monitoring of cardiac functions for real-time diagnostics, we propo...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Nonstationary Harmonic Modeling for ECG Removal in Surface EMG SignalsEmail this article to a colleague.
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We present a compact approach for mitigating the presence of electrocardiograms (ECG) in surface electromyographic (EMG) signals by means of time-variant harmonic modeling of the cardiac artifact. Heart rate and QRS complex variability, which often account for amplitude and frequency time variations of the ECG, are simultaneously captured by a set of third-order constant-coefficient polynomials modulating a stationary harmonic basis in the analysis window. Such a characterization allows us to significantly suppress ECG from the mixture by preserving most of the EMG signal content at low frequencies (less than 20 Hz)...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Automatic Detection and Quantification of Tree-in-Bud (TIB) Opacities From CT ScansEmail this article to a colleague.
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This study presents a novel computer-assisted detection (CAD) system for automatically detecting and precisely quantifying abnormal nodular branching opacities in chest computed tomography (CT), termed tree-in-bud (TIB) opacities by radiology literature. The developed CAD system in this study is based on 1) fast localization of candidate imaging patterns using local scale information of the images, and 2) Möbius invariant feature extraction method based on learned local shape and texture properties of TIB patterns. For fast localization of candidate imaging patterns, we use ball-scale filtering and, based on the obs...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Classification of Periodic Activities Using the Wasserstein DistanceEmail this article to a colleague.
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In this paper, we introduce a novel nonparametric classification technique based on the use of the Wasserstein distance. The proposed scheme is applied in a biomedical context for the analysis of recorded accelerometer data: the aim is to retrieve three types of periodic activities (walking, biking, and running) from a time–frequency representation of the data. The main interest of the use of the Wasserstein distance lies in the fact that it is less sensitive to the location of the frequency peaks than to the global structure of the frequency pattern, allowing us to detect activities almost independently of their sp...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Filter-Based Methodology for the Location of Hot Spots in Proteins and Exons in DNAEmail this article to a colleague.
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The so-called receiver operating characteristic technique is used as a tool in an optimization procedure for the improvement and assessment of a filter-based methodology for the location of hot spots in protein sequences and exons in DNA sequences. By optimizing the characteristic values of the nucleotides, high efficiency as well as improved accuracy can be achieved relative to results obtained with the electron–ion interaction potentials. On the other hand, by using the proposed filter-based methodology with binary sequences, improved accuracy can be achieved although the efficiency is somewhat compromised relativ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
A Multiscale Model for Bioimpedance Dispersion of Liver TissueEmail this article to a colleague.
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This study demonstrates the potential of a multiscale model in determining the stoppage of blood flow during surgery.
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Modeling the Field Distribution in Deep Brain Stimulation: The Influence of Anisotropy of Brain TissueEmail this article to a colleague.
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The neurosurgical method of deep brain stimulation (DBS) is used to treat symptoms of movement disorders like Parkinson’s disease by implanting stimulation electrodes in deep brain areas. The aim of this study was to examine the field distribution in DBS and the role of heterogeneous and anisotropic material properties in the brain areas where stimulation is applied. Finite element models of the human brain were developed comprising tissue heterogeneity and anisotropy. The tissue data were derived from averaged magnetic resonance imaging and diffusion tensor imaging datasets. Unilateral stimulation of the subthalami...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Extrapolatable Analytical Functions for Tendon Excursions and Moment Arms From Sparse DatasetsEmail this article to a colleague.
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We present a novel method that simultaneously estimates both the form and parameter values of arbitrary analytical expressions for tendon excursions and moment arms over the entire range of motion from sparse datasets. This symbolic regression method based on genetic programming has been shown to find the appropriate form of mathematical expressions that capture the physics of mechanical systems. We demonstrate this method by applying it to 1) experimental data from a physical tendon-driven robotic system with arbitrarily routed multiarticular tendons and 2) synthetic data from musculoskeletal models. We show it outperform...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
A State-Space Modeling Approach for Localization of Focal Current Sources From MEGEmail this article to a colleague.
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In this study, we propose a novel state-space model-based method that resolves these problems, extending our previous source localization method to include a temporal constraint by state-space modeling. To enable focal current reconstruction, we account for spatially inhomogeneous temporal dynamics by introducing dynamics model parameters that differ for each cortical position. The model parameters and the intensity of the current sources are jointly estimated according to a Bayesian framework. We circumvent the high dimensionality of the problem by assuming prior distributions of the model parameters to reduce the sensiti...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Neural Network Incorporating Meal Information Improves Accuracy of Short-Time Prediction of Glucose ConcentrationEmail this article to a colleague.
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Diabetes mellitus is one of the most common chronic diseases, and a clinically important task in its management is the prevention of hypo/hyperglycemic events. This can be achieved by exploiting continuous glucose monitoring (CGM) devices and suitable short-term prediction algorithms able to infer future glycemia in real time. In the literature, several methods for short-time glucose prediction have been proposed, most of which do not exploit information on meals, and use past CGM readings only. In this paper, we propose an algorithm for short-time glucose prediction using past CGM sensor readings and information on carboh...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Embedding Topic Discovery in Conditional Random Fields Model for Segmenting Nuclei Using Multispectral DataEmail this article to a colleague.
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Segmentation of cells/nuclei is a challenging problem in 2-D histological and cytological images. Although a large number of algorithms have been proposed, newer efforts continue to be devoted to investigate robust models that could have high level of adaptability with regard to considerable amount of image variability. In this paper, we propose a multiclassification conditional random fields (CRFs) model using a combination of low-level cues (bottom–up) and high-level contextual information (top–down) for separating nuclei from the background. In our approach, the contextual information is extracted by an un...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Phantom Model of Physiologic Intracranial Pressure and Cerebrospinal Fluid DynamicsEmail this article to a colleague.
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We describe herein a novel life-size phantom model of the intracranial cavity and its validation. The cerebrospinal fluid (CSF) domains including ventricular, cysternal, and subarachnoid spaces were derived via magnetic resonance imaging. Brain mechanical properties and cranio-spinal compliance were set based on published data. Both bulk and pulsatile physiologic CSF flow were modeled. Model validation was carried out by comparisons of flow and pressure measurements in the phantom with published in vivo data of healthy subjects. Physiologic intracranial pressure with 10 mmHg mean and 0.4 mmHg peak pulse amplitude was recor...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Depth Discontinuity-Based Cup Segmentation From Multiview Color Retinal ImagesEmail this article to a colleague.
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Accurate segmentation of the cup region from retinal images is needed to derive relevant measurements for glaucoma assessment. A novel, depth discontinuity (in the retinal surface)-based approach to estimate the cup boundary is proposed in this paper. The proposed approach shifts focus from the cup region used by existing approaches to cup boundary. The given set of images, acquired sequentially, are related via a relative motion model and the depth discontinuity at the cup boundary is determined from cues such as motion boundary and partial occlusion. The information encoded by these cues is used to approximate the cup bo...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Electrodiffusion of Molecules in Aqueous Media: A Robust, Discretized Description for Electroporation and Other Transport PhenomenaEmail this article to a colleague.
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Electrically driven transport of molecules and ions within aqueous electrolytes is of long-standing interest, with direct relevance to applications that include the delivery/release of biologically active solutes to/from cells and tissues. Examples include iontophoretic and electroporation-mediated drug delivery. Here, we describe a robust method for characterizing electrodiffusive transport in physiologic aqueous media. Specifically, we treat the case of solute present in sufficiently low concentration as to negligibly contribute to the total ionic current within the system. In this limiting case, which applies to many sy...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Biodegradable Microfabricated Plug-Filters for Glaucoma Drainage DevicesEmail this article to a colleague.
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We report on the development of a batch fabricated biodegradable truncated-cone-shaped plug filter to overcome the postoperative hypotony in nonvalved glaucoma drainage devices. Plug filters are composed of biodegradable polymers that disappear once wound healing and bleb formation has progressed past the stage where hypotony from overfiltration may cause complications in the human eye. The biodegradable nature of device eliminates the risks associated with permanent valves that may become blocked or influence the aqueous fluid flow rate in the long term. The plug-filter geometry simplifies its integration with commercial ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Automatic Motion and Noise Artifact Detection in Holter ECG Data Using Empirical Mode Decomposition and Statistical ApproachesEmail this article to a colleague.
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We present a real-time method for the detection of motion and noise (MN) artifacts, which frequently interferes with accurate rhythm assessment when ECG signals are collected from Holter monitors. Our MN artifact detection approach involves two stages. The first stage involves the use of the first-order intrinsic mode function (F-IMF) from the empirical mode decomposition to isolate the artifacts’ dynamics as they are largely concentrated in the higher frequencies. The second stage of our approach uses three statistical measures on the F-IMF time series to look for characteristics of randomness and variability, whic...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Table of ContentsEmail this article to a colleague.
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Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
IEEE Transactions on Biomedical Engineering publication informationEmail this article to a colleague.
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Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
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Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research
Upstream process optimization of polyhydroxybutyrate (PHB) by Alcaligenes latus using two-stage batch and fed-batch fermentation strategies.Email this article to a colleague.
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Abstract
This research focused on optimizing the upstream process time for production of polyhydroxybutyrate (PHB) from sucrose by two-stage batch and fed-batch fermentation with Alcaligenes latus ATCC 29714. The study included selection of strain, two-stage batch fermentations with different time points for switching to nitrogen limited media (14, 16 or 18 h) and fed-batch fermentations with varied time points (similar to two stage) for introducing nitrogen limited media. The optimal strain to produce PHB using sucrose as carbon source was A. latus ATCC 29714 with maximum-specific growth rate of 0.38 ± 0.01 h...
Source: Bioprocess and Biosystems Engineering - May 18, 2012 Category: Biomedical Engineering Authors: Wang B, Sharma-Shivappa RR, Olson JW, Khan SA Tags: Bioprocess Biosyst Eng Source Type: research
Effect of enzymes on anaerobic digestion of primary sludge and septic tank performance.Email this article to a colleague.
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In this study, batch reactors and continuous-flow reactors designed and operated as septic tanks were used to evaluate whether enzymatic treatment would increase the hydrolysis and digestion rates in primary sludge. Total solids, volatile solids, total suspended solids, total and soluble chemical oxygen demand, concentrations of protein, carbohydrate, ammonia and volatile acids in sludge and effluent samples were measured to determine the differences in digestion rates in the presence and absence of enzymes. Overall, no significant improvement was observed in enzyme-treated reactors compared with the control reactors.
...
Source: Bioprocess and Biosystems Engineering - May 18, 2012 Category: Biomedical Engineering Authors: Diak J, Ormeci B, Kennedy KJ Tags: Bioprocess Biosyst Eng Source Type: research
Regional Prediction of Tissue Fate in Acute Ischemic Stroke.Email this article to a colleague.
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We present a quantitative predictive model of tissue fate that combines regional imaging features available after onset. A key component is the use of cuboids randomly sampled during the learning process. Models trained with time-to-maximum feature (Tmax) computed from perfusion weighted images (PWI) are compared to the ones obtained from the apparent diffusion coefficient (ADC). The prediction task is formalized as a regression problem where the inputs are the local cuboids extracted from Tmax or ADC images at onset, and the output is the segmented FLAIR intensity of the tissue 4 days after intervention. Experiments on 2...
Source: Annals of Biomedical Engineering - May 17, 2012 Category: Biomedical Engineering Authors: Scalzo F, Hao Q, Alger JR, Hu X, Liebeskind DS Tags: Ann Biomed Eng Source Type: research
Corrigendum.Email this article to a colleague.
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Authors:
PMID: 22594456 [PubMed - as supplied by publisher]
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 17, 2012 Category: Biomedical Engineering Tags: Comput Methods Biomech Biomed Engin Source Type: research
Development and validation of a multi-body model of the canine stifle joint.Email this article to a colleague.
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Abstract
Multi-body musculoskeletal models that can be used concurrently to predict joint contact pressures and muscle forces would be extremely valuable in studying the mechanics of joint injury. The purpose of this study was to develop an anatomically correct canine stifle joint model and validate it against experimental data. A cadaver pelvic limb from one adult dog was used in this study. The femoral head was subjected to axial motion in a mechanical tester. Kinematic and force data were used to validate the computational model. The maximum RMS error between the predicted and measured kinematics during the comp...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 17, 2012 Category: Biomedical Engineering Authors: Stylianou AP, Guess TM, Cook JL Tags: Comput Methods Biomech Biomed Engin Source Type: research
Establishment of cultivating strategy for highly aggregated mycelia of Morchella esculenta in a stirred-tank bioreactor.Email this article to a colleague.
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Abstract
Mycelia of Morchella esculenta were found to aggregate rapidly in a submerged culture, which caused the decrease in dispersed mycelia and the problem of diffusion limitation. The effect of different agitation schemes on the growth of mycelia was investigated in a stirred-tank bioreactor. At the constant speed of 100 or 300 rpm, rapid aggregation caused the biomass concentration to drop to zero in 30 h, which was even worse than achieved under static culture. Intermittent agitation maintained a higher mycelium fragment concentration for 48 h and enhanced the biomass concentration to 4.73 g/L at 120 h. ...
Source: Bioprocess and Biosystems Engineering - May 17, 2012 Category: Biomedical Engineering Authors: Ma TW, Xiao BY, Yang FC Tags: Bioprocess Biosyst Eng Source Type: research
Modeling the relationship between Higuchi’s fractal dimension and Fourier spectra of physiological signalsEmail this article to a colleague.
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Abstract The exact mathematical relationship between FFT spectrum and fractal dimension (FD) of an experimentally recorded signal is
not known. In this work, we tried to calculate signal FD directly from its Fourier amplitudes. First, dependence of Higuchi’s
FD of mathematical sinusoids on their individual frequencies was modeled with a two-parameter exponential function. Next,
FD of a finite sum of sinusoids was found to be a weighted average of their FDs, weighting factors being their Fourier amplitudes
raised to a fractal degree. Exponent dependence on frequency was modeled with exponential, power and l...
Source: Medical and Biological Engineering and Computing - May 16, 2012 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: research
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Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
IEEE Xplore Digital LibraryEmail this article to a colleague.
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Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Renew your IEEE membership for 2012 and add Signal Processing SocietyEmail this article to a colleague.
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Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
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Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
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Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Improved Lattice Reduction-Aided MIMO Successive Interference Cancellation Under Imperfect Channel EstimationEmail this article to a colleague.
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Lattice reduction (LR) and successive interference cancellation (SIC) are two well-known techniques that can be used to improve detection performance over linear detectors for multiple-input multiple-output (MIMO) systems. However, the LR technique and the SIC technique usually need perfect knowledge on the channel at the receiver, and the use of these techniques with an erroneous channel matrix even worsens the detection performance compared to linear detectors. In this correspondence, we shall show how to modify these techniques to make them robust under imperfect channel estimation. Information needed for the proposed a...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Techniques for MIMO Channel Covariance Matrix QuantizationEmail this article to a colleague.
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In this correspondence, we develop techniques to efficiently quantize channel covariance matrices in multiple-input multiple-output (MIMO) Rayleigh fading environments. While these covariance matrices change less frequently than the channel matrices themselves, this information needs to be updated when it does change. Furthermore, these covariance matrices have significantly more parameters to quantize than their channel matrix counterparts. Since many applications focus on utilizing the strongest eigenmodes of the channel covariance matrix and since these matrices tend to be low-rank, we focus on efficiently quantizing th...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Optimal Joint Spatial and Temporal Power Adaptation for Space-Time-Coded Systems With Imperfect CSIEmail this article to a colleague.
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In this correspondence, a joint optimization of spatio-temporal (S-T) power allocation to minimize the average bit error rate (BER) subject to an average power constraint is developed for beamforming orthogonal space-time block coded multiantenna systems over flat Rayleigh fading channels in the presence of imperfect channel state information at the transmitter (CSIT). Compared to the spatial-only (S-O) power allocation methods, the optimal S-T strategy reduces BER significantly. It can be used as a benchmark to evaluate the existing suboptimal S-T schemes. A necessary and sufficient condition, which can determine the numb...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Single-Carrier Systems With MMSE Linear Equalizers: Performance Degradation due to Channel and CFO Estimation ErrorsEmail this article to a colleague.
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We assess the impact of the channel and the carrier frequency offset (CFO) estimation errors on the performance of single-carrier systems with MMSE linear equalizers. Performance degradation is caused by the fact that a mismatched MMSE linear equalizer is applied to channel output samples with imperfectly canceled CFO. Assuming a single-block training, we develop an asymptotic expression for the excess mean square error (EMSE) induced by the channel and CFO estimation errors and derive a simple EMSE approximation which reveals the following: 1) performance degradation is mainly caused by the imperfectly canceled CFO and 2)...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Persymmetric Parametric Adaptive Matched Filter for Multichannel Adaptive Signal DetectionEmail this article to a colleague.
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This correspondence considers a parametric approach for multichannel adaptive signal detection in Gaussian disturbance which can be modeled as a multichannel autoregressive (AR) process and, moreover, possesses a persymmetric structure induced by a symmetric antenna geometry. By introducing the persymmetric AR (PAR) modeling for the disturbance, a persymmetric parametric adaptive matched filter (Per-PAMF) is proposed. The developed Per-PAMF extends the classical PAMF by exploiting the underlying persymmetric properties and, hence, improves the detection performance in training-limited scenarios. The performance of the prop...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Steady State and Transient MSE Analysis of Convexly Constrained Mixture MethodsEmail this article to a colleague.
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We investigate convexly constrained mixture methods to adaptively combine outputs of two adaptive filters running in parallel to model a desired unknown system. We compare several algorithms with respect to their mean-square error in the steady state, when the underlying unknown system is nonstationary with a random walk model. We demonstrate that these algorithms are universal such that they achieve the performance of the best constituent filter in the steady state if certain algorithmic parameters are chosen properly. We also demonstrate that certain mixtures converge to the optimal convex combination filter such that th...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Robust RLS in the Presence of Correlated Noise Using Outlier SparsityEmail this article to a colleague.
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Relative to batch alternatives, the recursive least-squares (RLS) algorithm has well-appreciated merits of reduced complexity and storage requirements for online processing of stationary signals, and also for tracking slowly-varying nonstationary signals. However, RLS is challenged when in addition to noise, outliers are also present in the data due to, e.g., impulsive disturbances. Existing robust RLS approaches are resilient to outliers, but require the nominal noise to be white—an assumption that may not hold in e.g., sensor networks where neighboring sensors are affected by correlated ambient noise. Prewhitening...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
An Enhanced IAF-PNLMS Adaptive Algorithm for Sparse Impulse Response IdentificationEmail this article to a colleague.
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This correspondence presents an individual-activation-factor proportionate normalized least-mean-square (IAF-PNLMS) algorithm that (during the adaptive process) uses a new gain distribution strategy for updating the filter coefficients. This strategy consists of increasing the gain assigned to the inactive coefficients as the active ones approach convergence. For such, whenever a predefined threshold is crossed during the learning process, a new gain distribution is carried out, rather than to assign gains proportional to coefficient magnitudes as the IAF-PNLMS algorithm does. This new version of the IAF-PNLMS algorithm le...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Generalization Error of Linear Discriminant Analysis in Spatially-Correlated Sensor NetworksEmail this article to a colleague.
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Generalization error, the probability of error of a detection rule learned from training samples on new unseen samples, is a fundamental quantity to be characterized. However, characterizations of generalization error in the statistical learning theory literature are often loose and practically unusable for optimizing detection systems. In this work, focusing on learning linear discriminant analysis detection rules from spatially-correlated sensor measurements, a tight generalization error approximation is developed that can be used to optimize the parameters of a sensor network detection system. As such, the approximation...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Distributed SNR Estimation With Power Constrained Signaling Over Gaussian Multiple-Access ChannelsEmail this article to a colleague.
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A sensor network is used for distributed signal-to-noise ratio (SNR) estimation in a single-time snapshot. Sensors observe a signal embedded in noise, and each observation is phase modulated using a constant-modulus scheme and transmitted over a Gaussian multiple-access channel to a fusion center. At the fusion center, the mean and variance are estimated jointly, using an asymptotically minimum-variance estimator. It is shown that this joint estimator decouples into simple individual estimators of the mean and the variance. The constant-modulus phase modulation scheme ensures a fixed transmit power, robust estimation acros...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
On Partial Downloading for Wireless Distributed Storage NetworksEmail this article to a colleague.
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We consider a distributed storage system employing some existing regenerate codes where the storage nodes are scattered in a wireless network. The data collector connects to the storage nodes via orthogonal channels and downloads data symbols from these nodes. In the existing data reconstruction schemes for distributed storage systems, the data collector downloads all symbols from a subset of the storage nodes. Such a full-downloading approach becomes inefficient in wireless networks since due to fading, the wireless channels may not offer sufficient bandwidths for full downloading. Moreover, full-downloading is also less ...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Iterative Superlinear-Convergence SVD Beamforming Algorithm and VLSI Architecture for MIMO-OFDM SystemsEmail this article to a colleague.
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In this paper, we propose a singular value decomposition (SVD) algorithm with superlinear-convergence rate, which is suitable for the beamforming mechanism in MIMO-OFDM channels with short coherent time, or short training sequence. The proposed superlinear-convergence SVD (SL-SVD) algorithm has the following features: 1) superlinear-convergence rate; 2) the ability of being extended smaller numbers of transmit and receive antennas; 3) being insensitive to dynamic range problems during the iterative process in hardware implementations; and 4) low computational cost. We verify the proposed design by using the VLSI implementa...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
Minimizing Access Cost for Multiple Types of Memory Units in Embedded Systems Through Data Allocation and SchedulingEmail this article to a colleague.
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Software-controlled memories, such as scratch-pad memory (SPM), have been widely adopted in many digital signal processors to achieve high performance with low cost. Multiple types of memory units with varying performance and cost can be found in one system. In this paper, we design a polynomial-time algorithm, the regional optimal data allocation (RODA) algorithm, using dynamic programming approach. It guarantees optimal data allocation with minimal access cost for a program region. A polynomial-time algorithm, the global data allocation (GDA) algorithm, is proposed to reduce access cost efficiently based on regional resu...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research
