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This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 20.

Confinement dependent chemotaxis in two-photon polymerized linear migration constructs with highly definable concentration gradients.
Abstract Dendritic cell chemotaxis is known to follow chemoattractant concentration gradients through tissue of heterogeneous pore sizes, but the dependence of migration velocity on pore size and gradient steepness is not fully understood. We enabled chemotaxis studies for at least 42 hours at confinements relevant to tissue models by two-photon polymerization of linear channel constructs with cross-sections from 10 × 10 μm(2) to 20 × 20 μm(2) inside commercially available chemotaxis analysis chips. Faster directed migration was observed with decreasing channel dimensions despite substantial cell def...
Source: Biomedical Microdevices - February 15, 2015 Category: Biomedical Engineering Authors: Hjortø GM, Olsen MH, Svane IM, Larsen NB Tags: Biomed Microdevices Source Type: research

Characterization of salt-tolerant β-glucosidase with increased thermostability under high salinity conditions from Bacillus sp. SJ-10 isolated from jeotgal, a traditional Korean fermented seafood.
Abstract The β-glucosidase gene, bglC, was cloned from Bacillus sp. SJ-10 isolated from the squid jeotgal. Recombinant BglC protein overexpression was induced in Escherichia coli. The optimal pH and temperature of the enzyme, using p-nitrophenyl-β-D-glucopyranoside (pNPβGlc) as a substrate, were pH 6 and 40 °C, respectively. Enzymatic activity increased by 3.3- and 3.5-fold in the presence of 15 % NaCl and KCl, respectively. Furthermore, enzyme thermostability improved in the presence of NaCl or KCl. At 45 °C in the presence of salts, the enzyme was stable for 2 h and maintained 80 % activity. In the abse...
Source: Bioprocess and Biosystems Engineering - February 15, 2015 Category: Biomedical Engineering Authors: Lee JM, Kim YR, Kim JK, Jeong GT, Ha JC, Kong IS Tags: Bioprocess Biosyst Eng Source Type: research

Optimization of dual slot antenna using floating metallic sleeve for microwave ablation
In this study, we optimized dual slot antenna to yield reduction in backward heating pattern along the antenna shaft with the application of floating metallic sleeve. Finite element methods were used to generate the electromagnetic (EM) field and thermal distribution in liver tissue. The position of the sleeve from the tip of the probe (z = 0 mm) was varied within the range 14 ≤ z ≤ 22 mm while sleeve length was varied within 16 ≤ z ≤ 48 mm at 2 mm interval using operating frequency of 2.45 GHz. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - February 14, 2015 Category: Biomedical Engineering Authors: Z.A. Ibitoye, E.O. Nwoye, M.A. Aweda, A.A. Oremosu, C.C. Annunobi, O.N. Akanmu Source Type: research

A mathematical model approach quantifying patients’ response to changes in mechanical ventilation: Evaluation in volume support
Setting mechanical ventilation (MV) is difficult, with suboptimal settings increasing the risk of overloading the respiratory muscles, lung injury and organ system failure [1–3]. MV can be seen as a trade-off between conflicting goals [4], including the balance between: poor oxygenation and oxygen toxicity, ventilator induced lung injury and acidosis; and in support modes of ventilation, respiratory stress and effects of prolonged MV. Computer-based protocols have been developed to assist in setting the ventilator, encouraging reduction in support without overly stressing patients and keeping them within a comfort zone o...
Source: Medical Engineering and Physics - February 14, 2015 Category: Biomedical Engineering Authors: S. Larraza, N. Dey, D.S. Karbing, J.B. Jensen, M. Nygaard, R. Winding, S.E. Rees Source Type: research

Comparing the performances of circular ponds with different impellers by CFD simulation and microalgae culture experiments.
In this study, a numerical simulation using computational fluid dynamics (CFD) was used to investigate the hydrodynamic characteristics of circular ponds with three different impellers (hydrofoil, four-pitched-blade turbine, and grid plate). The reliability of the CFD model was validated by particle image velocimetry (PIV). Hydrodynamic analyses were conducted to evaluate the average velocity magnitude along the light direction (U z), turbulence properties, average shear stress, pressure loss and the volume percentage of dead zone inside circular ponds. The simulation results showed that U z value of hydrofoil was 58.9, 40...
Source: Bioprocess and Biosystems Engineering - February 14, 2015 Category: Biomedical Engineering Authors: Meng C, Huang J, Ye C, Cheng W, Chen J, Li Y Tags: Bioprocess Biosyst Eng Source Type: research

Collagen Structure and Mechanical Properties of the Human Sclera: Analysis for the Effects of Age
The objective of this study was to measure the collagen fiber structure and estimate the material properties of 7 human donor scleras, from age 53 to 91. The specimens were subjected to inflation testing, and the full-field displacement maps were measured by digital image correlation. After testing, the collagen fiber structure was mapped using wide-angle X-ray scattering. A specimen-specific inverse finite element method was applied to calculate the material properties of the collagen fibers and interfiber matrix by minimizing the difference between the experimental displacements and model predictions. Age effects on the ...
Source: Journal of Biomechanical Engineering - February 13, 2015 Category: Biomedical Engineering Source Type: research

Mass Transport of Low Density Lipoprotein in Reconstructed Hemodynamic Environments of Human Carotid Arteries: The Role of Volume and Solute Flux Through the Endothelium
In this study we examine subject-specific LDL transport into the intima of carotid bifurcations in three human subjects using a three-pore model for LDL mass transfer. Subject-specific carotid artery computational models were derived using magnetic resonance imaging (MRI) to obtain the geometry and phase-contract MRI (PC-MRI) to acquire pulsatile inflow and outflow boundary conditions for each subject. The subjects were selected to represent a wide range of anatomical configurations and different stages of atherosclerotic development from mild to moderate intimal thickening. A fluid–solid interaction (FSI) model was impl...
Source: Journal of Biomechanical Engineering - February 13, 2015 Category: Biomedical Engineering Source Type: research

Design of a Pulsatile Flow Facility to Evaluate Thrombogenic Potential of Implantable Cardiac Devices
This article presents a completely hemocompatible small-volume test-platform that can be used for thrombogenicity studies and experimental fluid mechanics characterization. Using a programmable piston pump to drive freshly drawn human blood inside a cylindrical column, the presented system can simulate various physiological and pathophysiological conditions in testing PHVs. The system includes a modular device-mounting chamber, and in this presented case, a 23 mm St. Jude Medical (SJM) Regents® mechanical heart valve (MHV) in aortic position was used as the test device. The system was validated for its capability to qua...
Source: Journal of Biomechanical Engineering - February 13, 2015 Category: Biomedical Engineering Source Type: research

Spatial DCT-Based Channel Estimation in Multi-Antenna Multi-Cell Interference Channels
This work addresses channel estimation in multiple antenna multicell interference-limited networks. Channel state information (CSI) acquisition is vital for interference mitigation. Wireless networks often suffer from multicell interference, which can be mitigated by deploying beamforming to spatially direct the transmissions. The accuracy of the estimated CSI plays an important role in designing accurate beamformers that can control the amount of interference created from simultaneous spatial transmissions to mobile users. Therefore, a new technique based on the structure of the spatial covariance matrix and the discrete ...
Source: IEEE Transactions on Signal Processing - February 13, 2015 Category: Biomedical Engineering Source Type: research

Greedy Sparsity-Promoting Algorithms for Distributed Learning
This paper focuses on the development of novel greedy techniques for distributed learning under sparsity constraints. Greedy techniques have widely been used in centralized systems due to their low computational requirements and at the same time their relatively good performance in estimating sparse parameter vectors/signals. The paper reports two new algorithms in the context of sparsity-aware learning. In both cases, the goal is first to identify the support set of the unknown signal and then to estimate the nonzero values restricted to the active support set. First, an iterative greedy multistep procedure is developed, ...
Source: IEEE Transactions on Signal Processing - February 13, 2015 Category: Biomedical Engineering Source Type: research

Generalized Coprime Array Configurations for Direction-of-Arrival Estimation
A coprime array uses two uniform linear subarrays to construct an effective difference coarray with certain desirable characteristics, such as a high number of degrees-of-freedom for direction-of-arrival (DOA) estimation. In this paper, we generalize the coprime array concept with two operations. The first operation is through the compression of the inter-element spacing of one subarray and the resulting structure treats the existing variations of coprime array configurations as well as the nested array structure as its special cases. The second operation exploits two displaced subarrays, and the resulting coprime array st...
Source: IEEE Transactions on Signal Processing - February 13, 2015 Category: Biomedical Engineering Source Type: research

Maximum Likelihood Passive and Active Sensing of Wideband Power Spectra From Few Bits
Wideband power spectrum sensing is essential for cognitive radio and many other applications. Aiming to crowdsource spectrum sensing operations, a novel frugal sensing framework was recently proposed, employing a network of low duty-cycle sensors (e.g., running in background mode on consumer devices) reporting randomly filtered broadband power measurement bits to a fusion center, which in turn estimates the ambient power spectrum. Frugal sensing is revisited here from a statistical estimation point of view. Taking into account fading and insufficient sample averaging considerations, maximum likelihood (ML) formulations are...
Source: IEEE Transactions on Signal Processing - February 13, 2015 Category: Biomedical Engineering Source Type: research

Annonce - CommuniquePresseLancement Concours TMI 2015
Publication date: February 2015 Source:IRBM News, Volume 36, Issue 1 (Source: IRBM News)
Source: IRBM News - February 13, 2015 Category: Biomedical Engineering Source Type: research

Forced oscillations and respiratory system modeling in adults with cystic fibrosis
Background: The Forced Oscillation Technique (FOT) has the potential to increase our knowledge about the biomechanical changes that occur in Cystic Fibrosis (CF). Thus, the aims of this study were to investigate changes in the resistive and reactive properties of the respiratory systems of adults with CF. Methods: The study was conducted in a group of 27 adults with CF over 18?years old and a control group of 23 healthy individuals, both of which were assessed by the FOT, plethysmography and spirometry. An equivalent electrical circuit model was also used to quantify biomechanical changes and to gain physiological insight....
Source: BioMedical Engineering OnLine - February 13, 2015 Category: Biomedical Engineering Authors: Adma LimaAlvaro FariaAgnaldo LopesJosé JansenPedro Melo Source Type: research

A tracer liquid image velocimetry for multi-layer radial flow in bioreactors
Conclusions: TLIV avoided the contradiction between the particles? visibility and following performance with tested fluid, which is difficult to overcome in PIV. And TLIV is easier to popularize for its simple experimental condition and low cost. (Source: BioMedical Engineering OnLine)
Source: BioMedical Engineering OnLine - February 13, 2015 Category: Biomedical Engineering Authors: Yu-Bao GaoJiu-Xing LiangYu-Xi LuoJia Yan Source Type: research

Low-Intensity Pulsed Ultrasound in Dentofacial Tissue Engineering.
Abstract Oral and maxillofacial diseases affect millions of people worldwide and hence tissue engineering can be considered an interesting and clinically relevant approach to regenerate orofacial tissues after being affected by different diseases. Among several innovations for tissue regeneration, low-intensity pulsed ultrasound (LIPUS) has been used extensively in medicine as a therapeutic, operative, and diagnostic tool. LIPUS is accepted to promote bone fracture repair and regeneration. Furthermore, the effect of LIPUS on soft tissues regeneration has been paid much attention, and many studies have performed to ...
Source: Annals of Biomedical Engineering - February 12, 2015 Category: Biomedical Engineering Authors: Tanaka E, Kuroda S, Horiuchi S, Tabata A, El-Bialy T Tags: Ann Biomed Eng Source Type: research

Automated system for lung nodules classification based on wavelet feature descriptor and support vector machine
Conclusions: The CADx system presented is competitive with other literature systems in terms of sensitivity. The system reduces the complexity of classification by not performing the typical segmentation stage of most CADx systems. Additionally, the novelty of the algorithm is the use of a wavelet feature descriptor. (Source: BioMedical Engineering OnLine)
Source: BioMedical Engineering OnLine - February 12, 2015 Category: Biomedical Engineering Authors: Hiram Madero OrozcoOsslan Vergara VillegasVianey Cruz SánchezHumberto Ochoa DomínguezManuel Nandayapa Alfaro Source Type: research

Non-invasive determination of transcatheter pressure gradient in stenotic aortic valves: An analytical model
Aortic valve stenosis (AS), which causes considerable constriction of the flow passage, is one of the most frequent cardiovascular diseases and is the most common cause of the valvular replacements [1]. AS is considered as the most frequent cardiac disease after arterial hypertension and coronary artery diseases. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - February 12, 2015 Category: Biomedical Engineering Authors: Zahra Keshavarz-Motamed, Pouyan K. Motamed, Nima Maftoon Tags: Technical note Source Type: research

Computer based real time systems for analyzing cardiovascular response to orthostatic stress
Publication date: Available online 10 February 2015 Source:Biocybernetics and Biomedical Engineering Author(s): Munna Khan , Sharda Vashisth , Ritu Vijay , Ashok K. Salhan The cardiovascular response to orthostatic (gravitational) stress has been the focus of several researches in the past. Average values of hemodynamic variables, such as arterial pressure or heart rate are recorded during changes in posture for diagnosing orthostatic stress clinically. Different methods based on varied physical principles have been developed to measure these hemodynamic variables. Carotid artery is responsible for direction of blood flo...
Source: Biocybernetics and Biomedical Engineering - February 12, 2015 Category: Biomedical Engineering Source Type: research

Whole cell bioconversion of vitamin D3 to calcitriol using Pseudonocardia sp. KCTC 1029BP.
In conclusion, utilizing whole cells of Pseudonocardia sp. KCTC 1029BP together with the optimal bioconversion medium markedly enhanced the production of calcitriol from vitamin D3. PMID: 25666830 [PubMed - as supplied by publisher] (Source: Bioprocess and Biosystems Engineering)
Source: Bioprocess and Biosystems Engineering - February 11, 2015 Category: Biomedical Engineering Authors: Kang DJ, Im JH, Kang JH, Kim KH Tags: Bioprocess Biosyst Eng Source Type: research

Towards Optimal Design of Cancer Nanomedicines: Multi-stage Nanoparticles for the Treatment of Solid Tumors.
Abstract Conventional drug delivery systems for solid tumors are composed of a nano-carrier that releases its therapeutic load. These two-stage nanoparticles utilize the enhanced permeability and retention (EPR) effect to enable preferential delivery to tumor tissue. However, the size-dependency of the EPR, the limited penetration of nanoparticles into the tumor as well as the rapid binding of the particles or the released cytotoxic agents to cancer cells and stromal components inhibit the uniform distribution of the drug and the efficacy of the treatment. Here, we employ mathematical modeling to study the effect o...
Source: Annals of Biomedical Engineering - February 11, 2015 Category: Biomedical Engineering Authors: Stylianopoulos T, Economides EA, Baish JW, Fukumura D, Jain RK Tags: Ann Biomed Eng Source Type: research

Towards a Mathematical Formalism for Semi-stochastic Cell-Level Computational Modeling of Tumor Initiation.
Abstract A phenomenological model is formulated to model the early stages of tumor formation. The model is based on a cell-based formalism, where each cell is represented as a circle or sphere in two-and three dimensional simulations, respectively. The model takes into account constituent cells, such as epithelial cells, tumor cells, and T-cells that chase the tumor cells and engulf them. Fundamental biological processes such as random walk, haptotaxis/chemotaxis, contact mechanics, cell proliferation and death, as well as secretion of chemokines are taken into account. The developed formalism is based on the repre...
Source: Annals of Biomedical Engineering - February 11, 2015 Category: Biomedical Engineering Authors: Vermolen FJ, Meijden RP, Es MV, Gefen A, Weihs D Tags: Ann Biomed Eng Source Type: research

A Novel Low-Complexity Precoded OFDM System With Reduced PAPR
The computational complexity and peak-to-average power ratio (PAPR) of conventional precoded orthogonal frequency division multiplexing (OFDM) systems can be reduced using a T-OFDM precoded system based on the Walsh–Hadamard matrix. The present paper proposes a novel precoding scheme for further reducing the computational complexity and PAPR of T-OFDM. In the proposed scheme, the precoding matrix is combined with an inverse discrete Fourier transform to construct a new transform matrix at the transmitter. Notably, the transform matrix is both unitary and circulant, with each column being a perfect Gaussian integer s...
Source: IEEE Transactions on Signal Processing - February 10, 2015 Category: Biomedical Engineering Source Type: research

Designing Dual-Tone Radio Interferometric Positioning Systems
For many wireless sensor networks, high accuracy and low complexity localization techniques are crucial to their successful deployment. The radio interferometric positioning system (RIPS) has been introduced for accurate localization with low complexity. In this paper, a dual-tone radio interferometric positioning system (DRIPS) is proposed to localize multiple targets simultaneously. In DRIPS, multiple asynchronous targets emit dual-tone signals, and synchronous anchor receivers (nodes with known positions) extract phase information of low-frequency differential tones created by squaring the received dual-tone signals. Mu...
Source: IEEE Transactions on Signal Processing - February 10, 2015 Category: Biomedical Engineering Source Type: research

Design Control for Clinical Translation of 3D Printed Modular Scaffolds.
Abstract The primary thrust of tissue engineering is the clinical translation of scaffolds and/or biologics to reconstruct tissue defects. Despite this thrust, clinical translation of tissue engineering therapies from academic research has been minimal in the 27 year history of tissue engineering. Academic research by its nature focuses on, and rewards, initial discovery of new phenomena and technologies in the basic research model, with a view towards generality. Translation, however, by its nature must be directed at specific clinical targets, also denoted as indications, with associated regulatory requirements....
Source: Annals of Biomedical Engineering - February 10, 2015 Category: Biomedical Engineering Authors: Hollister SJ, Flanagan CL, Zopf DA, Morrison RJ, Nasser H, Patel JJ, Ebramzadeh E, Sangiorgio SN, Wheeler MB, Green GE Tags: Ann Biomed Eng Source Type: research

Guided bone regeneration produced by new mineralized and reticulated collagen membranes in critical-sized rat calvarial defects
The aim of this study was to evaluate the bone regenerative effect of glutaraldehyde (GA) cross-linking on mineralized polyanionic collagen membranes in critical-sized defects on rat calvarias. Bone calvarial defects were induced in Wistar rats, which were then divided into five groups: a sham group; a control group, which received a commercial membrane; and GA, 25GA, and 75GA groups, which received one of three different polyanionic collagen membranes mineralized by 0, 25, or 75 hydroxyapatite cycles and then cross-linked by GA. Bone formation was evaluated based on digital radiography and computerized tomography. Histolo...
Source: Experimental Biology and Medicine - February 9, 2015 Category: Research Authors: Verissimo, D. M., Leitao, R. F., Figueiro, S. D., Goes, J. C., Lima, V., Silveira, C. O., Brito, G. A. Tags: Biomedical Engineering Source Type: research

Isolation and characterization of multipotent mesenchymal stem cells in nasal polyps
This study aimed to investigate nasal polyp (NP) tissues as a potential new source of multipotent MSCs that maintain their stemness and differentiation potential following multiple rounds of passaging. NP tissues were obtained from 10 patients during endoscopic sinus surgery. After isolating and culturing NP-derived MSCs (npMSCs), the expression levels of the surface markers CD34, CD44, CD45, CD73, CD90, CD105, CD106, CD146 and human leukocyte antigens-class II DR antigen (HLA-DR) were estimated by flow cytometry. NpMSCs were cultured in chondrogenic, osteogenic, adipogenic, or neurogenic differentiation medium. The differ...
Source: Experimental Biology and Medicine - February 9, 2015 Category: Research Authors: Cho, J.-S., Park, J.-H., Kang, J.-H., Kim, S. E., Park, I.-H., Lee, H.-M. Tags: Biomedical Engineering Source Type: research

Role of xenogenous bovine platelet gel embedded within collagen implant on tendon healing: an in vitro and in vivo study
Surgical reconstruction of large Achilles tendon defects is demanding. Platelet concentrates may be useful to favor healing in such conditions. The characteristics of bovine platelet-gel embedded within a collagen-implant were determined in vitro, and its healing efficacy was examined in a large Achilles tendon defect in rabbits. Two cm of the left Achilles tendon of 60 rabbits were excised, and the animals were randomly assigned to control (no implant), collagen-implant, or bovine-platelet-gel-collagen-implant groups. The tendon edges were maintained aligned using a Kessler suture. No implant was inserted in the cont...
Source: Experimental Biology and Medicine - February 9, 2015 Category: Research Authors: Oryan, A., Moshiri, A., Meimandi-Parizi, A., Maffulli, N. Tags: Biomedical Engineering Source Type: research

Editorial: Rehabilitation Bioengineering.
PMID: 25663628 [PubMed - as supplied by publisher] (Source: Annals of Biomedical Engineering)
Source: Annals of Biomedical Engineering - February 7, 2015 Category: Biomedical Engineering Authors: Wolf A, Portnoy S, Gefen A Tags: Ann Biomed Eng Source Type: research

Timely Event Detection by Networked Learners
We consider a set of distributed learners that are interconnected via an exogenously-determined network. The learners observe different data streams that are related to common events of interest, which need to be detected in a timely manner. Each learner is equipped with a set of local classifiers, which generate local predictions about the common event based on the locally observed data streams. In this work, we address the following key questions: (1) Can the learners improve their detection accuracy by exchanging and aggregating information? (2) Can the learners improve the timeliness of their detections by forming clus...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

An Invariant Approach to Adaptive Radar Detection Under Covariance Persymmetry
In this paper, we propose a systematic and unifying framework to deal with adaptive radar detection in the presence of Gaussian interference sharing a persymmetric covariance structure. First, we determine the group of transformations which leaves the considered hypothesis testing problem unaltered; then, after reduction by sufficiency, we determine a maximal invariant statistic which is a four dimensional vector and significantly compresses the original observation space. Its first two components are the one-step and the two-step Generalized Likelihood Ratio Test decision statistics, respectively, whereas its last two ent...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Coded Distributed Diversity: A Novel Distributed Reception Technique for Wireless Communication Systems
In this paper, we consider a distributed reception scenario where a transmitter broadcasts a signal to multiple geographically separated receive nodes over fading channels, and each node forwards a few bits representing a processed version of the received signal to a fusion center. The fusion center then tries to decode the transmitted signal based on the forwarded information from the receive nodes and possible channel state information. We show that there is a strong connection between the problem of minimizing the symbol error probability at the fusion center in distributed reception and channel coding in coding theory....
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Generalized Non-Orthogonal Joint Diagonalization With LU Decomposition and Successive Rotations
Non-orthogonal joint diagonalization (NJD) free of prewhitening has been widely studied in the context of blind source separation (BSS) and array signal processing, etc. However, NJD is used to retrieve the jointly diagonalizable structure for a single set of target matrices which are mostly formulized with a single dataset, and thus is insufficient to handle multiple datasets with inter-set dependences, a scenario often encountered in joint BSS (J-BSS) applications. As such, we present a generalized NJD (GNJD) algorithm to simultaneously perform asymmetric NJD upon multiple sets of target matrices with mutually linked loa...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Second-Order Synchrosqueezing Transform or Invertible Reassignment? Towards Ideal Time-Frequency Representations
This paper considers the analysis of multicomponent signals, defined as superpositions of real or complex modulated waves. It introduces two new post-transformations for the short-time Fourier transform that achieve a compact time-frequency representation while allowing for the separation and the reconstruction of the modes. These two new transformations thus benefit from both the synchrosqueezing transform (which allows for reconstruction) and the reassignment method (which achieves a compact time-frequency representation). Numerical experiments on real and synthetic signals demonstrate the efficiency of these new transfo...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

On Bandlimited Signal Reconstruction From the Distribution of Unknown Sampling Locations
In remote sensing with a large array of spatially distributed sensors, localization of individual sensor nodes could be difficult. Motivated by the smart-dust paradigm, this work addresses the reconstruction of spatially bandlimited fields from samples taken at unknown but statistically distributed sampling locations. Periodic one-dimensional bandlimited fields are considered for sampling. Samples of the field at uniform independent and identically distributed locations are obtained. The statistical realization of the sampling locations is not known. First, it is shown that a bandlimited field cannot be uniquely determined...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Diffuse Multipath Exploitation for Adaptive Radar Detection
We deal with the problem of detecting point-like targets in diffuse multipath environments, modeling the target echo as the superposition of a deterministic signal with an unknown scaling factor (due to the direct path) plus a zero-mean complex circular symmetric Gaussian random vector with an unknown covariance matrix (accounting for the echoes from the glistening surface). We devise a constrained Generalized Likelihood Ratio Test (GLRT) for the resulting hypothesis testing problem, enforcing the primary data covariance matrix (due to both interference and multipath echoes) to belong to a neighborhood of the secondary dat...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Sparsity and Adaptivity for the Blind Separation of Partially Correlated Sources
Blind source separation (BSS) is a very popular technique to analyze multichannel data. In this context, the data are modeled as the linear combination of sources to be retrieved. For that purpose, standard BSS methods all rely on some discrimination principle, whether it is statistical independence or morphological diversity, to distinguish between the sources. However, dealing with real-world data reveals that such assumptions are rarely valid in practice: the signals of interest are more likely partially correlated, which generally hampers the performances of standard BSS methods. In this paper, we introduce a novel spa...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

An Order Optimal Policy for Exploiting Idle Spectrum in Cognitive Radio Networks
In this paper, a spectrum sensing policy employing recency-based exploration is proposed for cognitive radio networks. We formulate the problem of finding a spectrum sensing policy for multiband dynamic spectrum access as a stochastic restless multiarmed bandit problem with stationary unknown reward distributions. In cognitive radio networks, the multiarmed bandit problem arises when deciding where in the radio spectrum to look for idle frequencies that could be efficiently exploited for data transmission. We consider two models for the dynamics of the frequency bands: 1) the independent model where the state of the band e...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Cross-Layer Design of Distributed Sensing-Estimation With Quality Feedback— Part I: Optimal Schemes
This two-part paper presents a feedback-based cross-layer framework for distributed sensing and estimation of a dynamic process by a wireless sensor network (WSN). Sensor nodes wirelessly communicate measurements to the fusion center (FC). Cross-layer factors such as packet collisions and the sensing-transmission costs are considered. Each SN adapts its sensing-transmission action based on its own local observation quality and the estimation quality feedback from the FC under cost constraints for each SN. In this first part, the optimization complexity is reduced by exploiting the statistical symmetry and large network app...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Cross-Layer Design of Distributed Sensing-Estimation With Quality Feedback— Part II: Myopic Schemes
This two-part paper presents a feedback-based cross-layer framework for distributed sensing and estimation of a dynamic process by a wireless sensor network (WSN). Sensor nodes wirelessly communicate measurements to the fusion center (FC). Cross-layer factors such as packet collisions and the sensing-transmission costs are considered. Each SN adapts its sensing-transmission action based on its own local observation quality and the estimation quality feedback from the FC under cost constraints for each SN. In this second part, low-complexity myopic sensing-transmission policies (MPs) are designed to optimize a trade-off bet...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research

Robust Estimation of Transformation for Non-Rigid Registration
We introduce a new transformation estimation algorithm using the $L_{2}E$ estimator and apply it to non-rigid registration for building robust sparse and dense correspondences. In the sparse point case, our method iteratively recovers the point correspondence and estimates the transformation between two point sets. Feature descriptors such as shape context are used to establish rough correspondence. We then estimate the transformation using our robust algorithm. This enables us to deal with the noise and outliers which arise in the correspondence step. The transformation is specified in a functional space, more specificall...
Source: IEEE Transactions on Signal Processing - February 6, 2015 Category: Biomedical Engineering Source Type: research