Control of an air pressure actuated disposable bioreactor for cultivating heart valves

A disposable injection molded bioreactor for growing tissue-engineered heart valves is controlled to mimic the physiological heart cycle. Tissue-engineered heart valves, cultured from human stem cells, are a possible alternative for replacing failing aortic heart valves, where nowadays biological and mechanical heart valves are used. Growing and conditioning is done by mechanically stimulating the tissue in a bioreactor. The disposable injection molded bioreactor uses flexible membranes and steering valves to mimic a physiological heart cycle. In this work, an air pressure actuation control system for this bioreactor is designed. One membrane is position controlled to achieve a desired flow through the heart valve, while another membrane controls the aortic pressure. A third actuator controls a steering valve used to impose a resistance on the flow back to the first membrane, in order to control the heart valve closing pressure. Due to the repetitive character of the setpoints, repetitive controllers are designed and implemented. A high position tracking performance is achieved and pressure setpoints are mimicked successfully, while preventing large pressure oscillations and suppressing disturbances that could be damaging for the tissue heart valve. The control system allows full adjustability of operating conditions needed for the growing, conditioning and testing phases of tissue engineered heart valves.     

Spectral characterization and classification of Carpentier-Edwardsheart valves implanted in the aortic position

This paper demonstrates an improvement in the performance of spectral phonocardiography, combined with pattern recognition techniques for monitoring the condition of bioprosthetic heart valves. The analysis of the heart sounds is performed using a modified forward-backward overdetermined Prony's method. Results show that the condition of the bioprosthesis affects mostly the higher part of the spectrum (i.e., above 250 Hz) where no frequency components were found for malfunctioning cases. Therefore, the amplitudes of the three highest frequency components are used as the input vector of an adaptive single layer perceptron-based classifier to identify normal and malfunctioning classes. For the sample set examined, this method gives 100% correct discrimination between normal and malfunctioning Carpentier-Edwards (C-E) valves     

Multimodal emotion recognition based on peak frame selection from video

We present a fully automatic multimodal emotion recognition system based on three novel peak frame selection approaches using the video channel. Selection of peak frames (i.e., apex frames) is an important preprocessing step for facial expression recognition as they contain the most relevant information for classification. Two of the three proposed peak frame selection methods (i.e., MAXDIST and DEND-CLUSTER) do not employ any training or prior learning. The third method proposed for peak frame selection (i.e., EIFS) is based on measuring the “distance” of the expressive face from the subspace of neutral facial expression, which requires a prior learning step to model the subspace of neutral face shapes. The audio and video modalities are fused at the decision level. The subject-independent audio-visual emotion recognition system has shown promising results on two databases in two different languages (eNTERFACE and BAUM-1a).     

An Arrhythmia?Anomalous Beat Monitoring System

An electronic monitoring system has been developed to detect the four conditions that usually lead to fibrillation in the infarcted heart. Artifact-free QRS detection is accomplished by passing the preamplified QRS through a bandpass filter, an automatic gain control (AGC)circuit, a full-wave rectifier, a nonlinear amplifier, and positive and negative slope detectors. High-threshold logic circuitry then applies the timing criteria necessary for positive identification of a QRS complex. A printout of the ECG is made if 1) the number of premature beats in the last minute exceeds a physician-set number (0 through 10), 2) the number of successive anomalous beats (i. e., area increase, QRS increase, or polarity reversal) exceeds a physician-set number (0 through 5), 3) an ``early' premature beat occurs (i.e., R-R' ? QT), or 4) a multiformal beat is detected (i.e., its morphology differs from that of the previous anomalous beat).     

Effects of Unphysiological Factors on Cardiac Output Regulation During Artificial Heart Pumping

Several Factors affecting artificial heart output were studied employing two mathematical models of prosthetic hearts, i.e., sac and diaphragm heart models. The stroke volume sensitivity to changes in venous pressure was analyzed by numerical computations. Increased inflow valve resistance, increased pump vacuum pressure, decreased elasticity of the ventricular sac or diaphragm and decreased size of the ventricle were shown to depress artificial heart function. In total prosthetic heart replacement experiments in calves, the resistance at the junction of the right heart to the natural atrium was measured by varying the pump vacuum pressure. When the vacuum pressure exceeded ?20 mmHg, the orifice resistance to flow increased approximately 4 times. Optimizing the above factors, a prosthetic heart should be designed that provides sufficient flow with a pump vacuum pressure not greater than ?20 mmHg.     

Four-chamber heart modeling and automatic segmentation for 3-D cardiac CT volumes using marginal space learning and steerable features

We propose an automatic four-chamber heart segmentation system for the quantitative functional analysis of the heart from cardiac computed tomography (CT) volumes. Two topics are discussed: heart modeling and automatic model fitting to an unseen volume. Heart modeling is a nontrivial task since the heart is a complex nonrigid organ. The model must be anatomically accurate, allow manual editing, and provide sufficient information to guide automatic detection and segmentation. Unlike previous work, we explicitly represent important landmarks (such as the valves and the ventricular septum cusps) among the control points of the model. The control points can be detected reliably to guide the automatic model fitting process. Using this model, we develop an efficient and robust approach for automatic heart chamber segmentation in 3-D CT volumes. We formulate the segmentation as a two-step learning problem: anatomical structure localization and boundary delineation. In both steps, we exploit the recent advances in learning discriminative models. A novel algorithm, marginal space learning (MSL), is introduced to solve the 9-D similarity transformation search problem for localizing the heart chambers. After determining the pose of the heart chambers, we estimate the 3-D shape through learning-based boundary delineation. The proposed method has been extensively tested on the largest dataset (with 323 volumes from 137 patients) ever reported in the literature. To the best of our knowledge, our system is the fastest with a speed of 4.0 s per volume (on a dual-core 3.2-GHz processor) for the automatic segmentation of all four chambers.      

A workstation-based system for 2-D echocardiography visualizationand image processing

Parameters of cardiac function can be drawn from the analysis of echocardiographic image sequences, especially the motion of the ventricular wall, heart wall thickness, and shape parameters. Automatic image analysis and visualization allows reduced manual operations and, above all, ensures objectivity and repetition of analysis, which is essential when one wishes to calculate parameters based on variations, i.e., on image sequence analysis. In this paper, a system and the related software package for interactive echocardiographic image analysis and visualization are illustrated and discussed. Furthermore, the full model for smoothing, edge enhancement, and contour detection is discussed and a new technique based on the heat anisotropic diffusion model is presented. The results of automatic detection of the left ventricle contours are presented and discussed.     

The Future of Systems, Man, and Cybernetics: Application Domains and Research Methods

Several important application areas that will dominate systems, man, and cybernetic (SMC) efforts for at least the next decade, together with the methods that will require further research and development in order to appropriately address these application domains, are considered herein. More specifically, four broad and pervasive system domains are examined: service systems, infrastructure and transportation systems, environmental and energy systems, and defense and space systems. Given the nature of these four application domains, a number of new systems [i.e., holistic-oriented, including system-of-systems (SoS)], man (i.e., decision-oriented, including decision informatics), and cybernetic (i.e., adaptive-oriented, including real-time control) methods are identified and their further development are discussed. Clearly, the IEEE Society on Systems, Man, and Cybernetics has a great future; its systems, man, and cybernetic methods are relevant for addressing challenging problems arising in system domains that are becoming dominant in this 21st century. However, the methods must be refined and expanded to meet the changing needs of the 21st century; from a system to a system-of-systems vision, from a disciplinary to a multidisciplinary outlook, from a mass production to a mass customization focus, from a steady state to a real-time perspective, and from an optimal to an adaptive approach.     

Contrast-independent curvilinear structure detection in biomedical images

Many biomedical applications require detection of curvilinear structures in images and would benefit from automatic or semiautomatic segmentation to allow high-throughput measurements. Here, we propose a contrast-independent approach to identify curvilinear structures based on oriented phase congruency, i.e., the phase congruency tensor (PCT). We show that the proposed method is largely insensitive to intensity variations along the curve and provides successful detection within noisy regions. The performance of the PCT is evaluated by comparing it with state-of-the-art intensity-based approaches on both synthetic and real biological images.     

Sharing of ARQ slots in Gilbert-Elliot channels

This letter treats the problem of m transmission slots sharing a pool of n automatic repeat request slots. Two cases are treated. In one, these m slots belong to the same base station-terminal pair, i.e., a frequency-division multiplexing channel. In the other, they are used by m different base station-terminal pairs, i.e., a time-division multiplexing channel. The smallest n to satisfy loss and delay requirement is determined.     

Comparing spectra of a series of point events particularly for heart rate variability data

Different methods for spectral analysis of the heart rate signal?considered as series of point events?are used in studies on heart rate variability. This paper compares these methods, focusing on the two principal ones: the interval spectrum, i.e., the spectrum of the interval series, and the spectrum of counts, which is related to the representation of the event series as a series of spikes (delta functions). Both autospectra are estimated for experimental heart rate data and are shown to produce similar results. This similarity is proven analytically, and it is shown that for small variations in interval length, the ratio of these spectra is PI(f)/PC(f) = [sin(?f?)/(?f?)]2, with PI and PC the interval spectrum and the spectrum of counts, respectively, f the frequency, and ?the mean interval length. It is concluded that both autospectra are equivalent for the considered heart rate data, but that, when relating the heart rate signal to other signals (e.g., respiration, blood pressure) by means of cross spectra, the technique to be used depends on the characteristics of the second signal.     

Identification‐Tagging of Methacrylate‐Based Intraocular Implants Using Sequence Defined Polyurethane Barcodes

Sequence‐coded polyurethanes are tested as anticounterfeiting tags for the labeling of methacrylate‐based intraocular implants. These sequence‐defined oligomers are prepared by solid‐phase iterative chemistry using two comonomers, allowing formation of a controlled 0/1 binary sequence. Tags with different sequences and chain lengths are synthesized and tested for lenses labeling. Two main methods are investigated for incorporating the tags in the intraocular implants. In the first approach, they are included in situ during the free‐radical copolymerization of 2‐ethoxyethyl methacrylate and ethylene glycol dimethylacrylate. In another strategy, premade lenses are swollen in a tetrahydrofuran solution containing the polyurethane tags and dried. Both approaches allow successful incorporation of the polyurethane labels in the methacrylate networks. In order to demonstrate this, the tags are extracted from the lenses using a solvent swelling protocol and analyzed by electrospray mass spectrometry. In all cases, the labels are found and their coded sequences can be identified by tandem mass spectrometry sequencing. These results indicate that sequence‐coded polyurethane tags represent a valid option for the labeling of implants. Importantly, it is shown in this work that the use of small weight fractions of polyurethane tag (i.e., 0.1–0.4 wt%) do not alter significantly the biocompatibility and transparency properties of the intraocular lenses.     

Detecting Space-Time Alternating Biological Signals Close to the Bifurcation Point

Time-alternating biological signals, i.e., alternans, arise in variety of physiological states marked by dynamic instabilities, e.g., period doubling. Normally, a sequence of large–small–large transients, they can exhibit variable patterns over time and space, including spatial discordance. Capture of the early formation of such alternating regions is challenging because of the spatiotemporal similarities between noise and the small-amplitude alternating signals close to the bifurcation point. We present a new approach for automatic detection of alternating signals in large noisy spatiotemporal datasets by exploiting quantitative measures of alternans evolution, e.g., temporal persistence, and by preserving phase information. The technique specifically targets low amplitude, relatively short alternating sequences and is validated by combinatorics-derived probabilities and empirical datasets with white noise. Using high-resolution optical mapping in live cardiomyocyte networks, exhibiting calcium alternans, we reveal for the first time early fine-scale alternans, close to the noise level, which are linked to the later formation of larger regions and evolution of spatially discordant alternans. This robust method aims at quantification and better understanding of the onset of cardiac arrhythmias and can be applied to general analysis of space-time alternating signals, including the vicinity of the bifurcation point.      

Adaptive equalisation of multipath interference for mobile videosignal reception

By using multiantenna diversity system to combat fading for mobile reception of video signals a nearly omnidirectional antenna pattern diagram can be achieved. However ghosts, especially fluttering ghosts, mainly caused by the fast rotating echo phases and RF signal level fluctuation, still affect the picture quality. It is shown that a single ghost cancelling reference (GCR)-signal is not sufficient for fluttering ghost suppression. A blind TV signal equalisation algorithm, which is based on image processing techniques, is developed to remove the interference of echoes with rapidly changing phases. A simplified version of this algorithm is included to reduce the computational load and allow suitable IC integration     

A computer-based-design approach to partitioning and mapping of computer logic graphs

A system of design automation computer programs is described which is capable of assigning blocks of a logic design to modules so as to satisfy certain constraints specified on the assignment. System features which enable designer-computer cooperation are discussed, and quality of solutions obtained with the system are compared to manual solutions for the same tasks. Three conclusions are reached. First, these computer programs make it possible to perform partitioning and mapping experiments which were not possible before. Second, for one-level partitions (e.g., logic gates on chips), highly automatic solutions obtained by the system are at least as good as manual solutions and are less costly to obtain. Third, for multilevel partitions (e.g., logic gates on chips on cards) or for mappings, the solutions obtained with the program are again at least as good as manual solutions; furthermore, the system allows a designer to try more alternatives than he could manually, so that he can trade off the time and cost of trying additional alternatives against the value of a better solution.     

Tucan

This paper presents Tucan, an approach to automatically create a virtual prototype (VP) and to support the analysis of VP testing results to validate time constraint requirements in real-time embedded systems. Virtual prototyping is a fast and reliable solution to facilitate system testing and time constraint validation. However, analyzing simulation results involves the visual inspection of timing diagrams, which is a time-consuming and complicated task. The complexity of the task grows depending on the number of signals present in a simulation; furthermore, their analysis is prone to errors due to the difficulty in identifying dependencies between the signals created by the system architecture. Our main contributions are: (1) the automatic generation of a high quality VP from a high level specification; (2) the specification of duration constraints, i.e., execution time of components that must be kept within an average time; and (3) duration requirement analysis based on predicted versus obtained behavior. We are able to predict system behavior by building a VP with a behavior model based on Time Petri Nets. We present the advantages of our method through a case study that illustrates the strength of Tucan in helping determine what variations at a specific component level allow the fulfillment of a set of time constraints.     

Parametric Analysis of Polyhedral Iteration Spaces

In the area of automatic parallelization of programs, analyzing and transforming loop nests with parametric affine loop bounds requires fundamental mathematical results. The most common geometrical model of iteration spaces, called the polytope model, is based on mathematics dealing with convex and discrete geometry, linear programming, combinatorics and geometry of numbers.In this paper, we present automatic methods for computing the parametric vertices and the Ehrhart polynomial, i.e., a parametric expression of the number of integer points, of a polytope defined by a set of parametric linear constraints.These methods have many applications in analysis and transformations of nested loop programs. The paper is illustrated with exact symbolic array dataflow analysis, estimation of execution time, and with the computation of the maximum available parallelism of given loop nests.     

A coplanar-waveguide system for cells exposure during electrophysiological recordings

In order to investigate the biological effects of microwave electromagnetic (EM) fields as those emitted from mobile telecommunication equipment, a suitable exposure system has been designed. The system is specific for real-time acquisition of membrane ionic currents in a biological cell, i.e., patch-clamp recordings. Both numerical and experimental characterizations are considered, in terms of EM field and specific absorption rate (SAR) distribution in the Petri dish containing the biological target. Results show a good efficiency of the system in terms of SAR induced in the sample by incident input power.     

全自动中文新闻字幕生成系统的设计与实现

本文设计与实现了一个全自动中文新闻字幕生成系统,输入为新闻视频,输出为视频对应的字幕文本.以<新闻联播>为语料,实现了音频提取、音频分类与切分、说话人识别、大词汇量连续语音识别、视频文件的播放和文本字幕的自动生成等多项功能.新闻字幕的自动生成,避免了繁重费时的人工字幕添加过程.实验表明,该系统识别率高,能够满足听障等特...     

External defibrillators and emergency external pacemakers

The first experimental defibrillation occurred in 1900. Zoll first achieved external defibrillation of a human heart in 1956 and the first commercial external manual defibrillators were introduced in 1961. The author discusses the steady improvements in manual defibrillator performance which have occurred since 1961, particularly relating to added functionality, event documentation, and telecommunications, and speculate on likely trends in the next few years. The author then considers the most important developments of the last 30 years, i.e., the development and successful use of smart automatic or advisory external defibrillators (AEDs) which are capable of accurately analyzing the ECG and of making reliable shock decisions. The first generation AEDs were intended for use by paramedics or nurses. There is growing interest in developing very simple, reliable, and low cast AEDs for widespread use by minimally trained first responders (e.g., fire fighters) and even lay persons (“public access defibrillation”) and existing of forthcoming AEDs for that application are discussed. Finally, the author briefly discusses external pacemakers and self-adhesive electrodes which have become common features of modern defibrillators