Relationship of Q penalty to eye-closure penalty for NRZ and RZ signals with signal-dependent noise

The relationship between Q penalty (QP) and eye-closure penalty (ECP) is examined for distorted signals in the presence of signal-dependent noise. A simple model is developed to describe the behavior of return-to-zero (RZ) modulation formats and is compared with a model for nonreturn-to-zero (NRZ) formats. The accuracy of the analysis is investigated with extensive simulations, and the numerical results from analysis and simulation are found to be in generally good agreement. Experimental measurements of distortion caused by uncompensated dispersion also show agreement with the simulation results and model predictions. The simplified models allow a means to budget QPs from distortion effects in a straightforward manner during network design for different modulation formats. The analysis predicts a smaller Q penalty as a function of ECP for RZ modulation formats in comparison with NRZ and smaller relative penalties for RZ formats with narrower pulsewidths.     

Mussel‐Inspired Conductive Cryogel as Cardiac Tissue Patch to Repair Myocardial Infarction by Migration of Conductive Nanoparticles

The engineered cardiac patch (ECP) is a promising strategy to repair infarct myocardium and restore the cardiac function. An ideal ECP should be able to mimic the primary attributes of native myocardium, which includes a high resilience, good cardiomyocyte adhesion, and synchronous contraction. Here, a mussel‐inspired dopamine crosslinker is used to integrate polypyrrole (Ppy) nanoparticles, gelatin‐methyacrylate, and poly(ethylene glycol) diacrylate into a cryogel form. The dopamine crosslinker and Ppy nanoparticles are coordinated to obtain optimal mechanical and superelastic properties for the ECP. The dopamine facilitates the uniform distribution of the Ppy nanoparticles, which migrate and fuse from the scaffold to the surface of the cardiomyocytes, revealing a potential mechanism for restoring infarct myocardium. The incorporated Ppy nanoparticles thus significantly enhance the functionalization of the cardiomyocytes, resulting in excellent synchronous contraction by increasing the expression of α‐actinin and CX‐43. Cardiomyocytes‐loaded ECP can improve the cardiac function in myocardial‐infarction (MI) affected rat models. The results show that the fractional shortening and ejection fraction are elevated by about 50% and that the infarct size is reduced by 42.6%. Collectively, this study highlights an effective cardiac patch based on mussel‐inspired conductive particle adhesion and a superelastic cryogel promising for the restoration of infarcted myocardium.     

Yielding optimized dependability assurance through bit inversion

Phase change memory (PCM) is a promising alternative to conventional DRAM main memories, due to its read performance, density, and nonvolatility and resulting low static energy. Unfortunately, reliability is still a significant challenge as limited write endurance, exacerbated by process variation, leads to increasing numbers of stuck-at faults over the memory's lifetime. This includes a significant number of stuck-at faults that appear early in the memory's service. Error-correcting Pointers (ECP) is a popular proposal to mitigate stuck-at faults in PCM by recording the addresses and the values of faulty bits in order to extend the lifetime of the memory. We propose a method to extend the effectiveness of ECP coverage called Yoda, which utilizes a small number of additional encoding bits in order to dramatically improve the effectiveness and fault correction capability of ECP. By adding one additional bit to ECP which corrects f faults, Yoda can correct 2f +1 faults. Further improvements are possible introducing small numbers additional bits. Our simulation results demonstrate that Yoda has a 3.0× improvement in fault coverage compared to a fault-aware ECP with a similar overhead, while also providing a 2.5–3.0× improvement over state-of-the-art schemes with comparable complexity. Furthermore, Yoda provides a method to protect the auxiliary bits, also with a small overhead. By adding one auxiliary bit to protect the auxiliary bits, Yoda can achieve extra improvement.     

基于VerilogHDL的IP核参数化设计

指出了IP核参数化设计的重要性,分析了IP核的参数类型及相互关系.在分析基于VerilogHDL的IP核参数化设计方法及所面临困难的基础上,提出了一种附加的编译预处理方法并设计了相应的工具软件ECP.IP核由VerilogHDL和ECP扩展的语句混合编程,经ECP处理后生成VerilogHDL源文件.应用该方法后,提高了Ver-ilogHDL在描述功能、性能、结构及优化策略等参数化的复杂模型时所需要的灵活性,增强了VerilogHDL的建模能力.作为一个IP核参数化设计的实例,介绍了C*Core系统中断控制IP的参数化设计过程,给出了FPGA验证的结果.     

Influence of plasma and inflammatory proteins on the ultrastructure of exogenous surfactant

We tested the hypothesis that albumin, fibrinogen and eosinophilic cationic protein (ECP) alter not only the function but also the ultrastructural composition of natural bovine surfactant (Alveofact). Therefore, natural bovine surfactant was mixed with equimolar concentrations of these proteins for 2 h and prepared for electron microscopical examination. Volume fractions, the volume to surface ratio and the volume-weighted mean volume were determined by using various stereological methods. Alveofact surface activity was tested with the capillary surfactometer. Native Alveofact-suspension contained mainly multilamellar bodies (numerous concentric predominantly fused compact phospholipid lamellae) and small fractions of multilamellar vesicles (several concentrically arranged lamellae with a less dense order) and unilamellar vesicles (one to two concentrically arranged phospholipid lamellae), but no tubular myelin. Addition of proteins to Alveofact led to a protein-dependent alteration in the distribution patterns of surfactant subtypes. The significant highest decrease in the volume fraction of multilamellar bodies was found in Alveofact-fibrinogen preparations and the lowest decrease was in Alveofact-albumin preparations. Interaction of Alveofact with ECP resulted in a significant decrease in the size of multilamellar bodies and a significant increase in the volume fraction of very small unilamellar and electron-dense vesicles. Alveofact with ECP kept test capillaries open for the shortest time, while Alveofact with albumin had little inhibitory effect. There was a significant correlation between percentage of capillary openness and the volume fraction quotient of inactive to active surfactant subtypes. Thus, equimolar concentrations of different proteins in Alveofact induce a conversion of multilamellar bodies combined with a decrease in surface activity. The most impressive structural alterations were found after mixture with ECP.     

Design of flexible GF(2/sup m/) elliptic curve cryptography processors

The design of flexible elliptic curve cryptography processors (ECP) is considered in this paper. Novel word-level algorithms and implementations for the underlying GF(2/sup m/) multiplication and squaring arithmetic which enable improved flexibility versus performance tradeoffs, are presented and employed in the design of an efficient flexible ECP architecture; corresponding field-programmable gate-array (FPGA) prototyping results for two different processor word lengths are also included for evaluation.     

Automated Osborn Wave Detection System Based on Wavelet Features and Neural Network

Automated Osborn wave detection system featuring the sensitivity of 94.63% and classification accuracy of 94.58% for the notch and slur types of waves in the cardiac signal has been developed. The quasi-matched wavelet filtering method and the method of principal components were applied for extraction and formation of feature vectors representing the input data of classifier. The error feedforward neural network with topology of a multilayer perceptron was used as a classifier. Signal samplings built on information from the PhysioNet open database of medical signals were used for training, testing and validation of neural network. This study involved the use of 12-lead electrocardiograms of 60 healthy patients aged 17–87. These electrocardiograms formed the basis for creating a database of 14832 signals (9888 with Osborn wave signals of two types and 4944 signals without pathological findings). The proposed approach ensured the classification accuracy exceeding the accuracy of existing techniques.     

Error prevention and concealment for scalable video coding with dual-priority transmission

In this work, we present an efficient error resilient system against ATM cell loss using a hybrid error concealment and error propagation prevention (ECP) technique with dual-priority transmission scheme (DPTS). DPTS performs traffic policing to form dual-priority cells in ATM connections and manages to make most cell losses occur in a low priority layer. However, cell loss may still occur in the high priority layer if the bandwidth is not reserved enough for the usually variable bitrate video traffic. Therefore, the ECP technique can still be utilized to reduce the error damage and limit the impact of cell loss to the erroneous slices. Simulation results of two-layer MPEG-2 coding over DPTS in ATM networks demonstrate that ECP with feedback over DPTS can effectively isolate errors and reduce the damage to yield a satisfactory performance, even when the cell-loss rate is as high as 8%.     

Development of an Asymmetric Hydrophobic/Hydrophilic Ultrathin Graphene Oxide Membrane as Actuator and Conformable Patch for Heart Repair

A conductive engineered cardiac patch (ECP) can reconstruct the biomimetic regenerative microenvironment of an infarcted myocardium. Direct ink writing (DIW) and 3D printing can produce an ECP with precisely controlled microarchitectures. However, developing a printed ECP with high conductivity and flexibility for gapless attachment to conform to epicardial geometry remains a challenge. Herein, an asymmetrical DIW hydrophobic/hydrophilic membrane using heat-processed graphene oxide (GO) ink is developed. The “Masked spin coating” method is also developed that leads to a microscale GO (hydrophilic)/reduced GO (rGO, hydrophobic) physiological sensor, as well as a macroscale moisture-driven GO/rGO actuator. Depositing mussel-inspired polydopamine (PDA) coating on the one side of the DIW rGO , the ultrathin (approximately 500 nm) PDA-rGO (hydrophilic)/rGO (hydrophobic) microlattice (DrGOM) ECP is bestowed with the flexibility and moisture-responsive actuation that allows gapless attachment to the curved surface of the epicardium. Conformable DrGOM exhibits a promising therapeutic effect on rats' infarcted hearts through conductive microenvironment reconstruction and improved neovascularization.     

Artificial neural networks for temperature dependent noise modeling of microwave transistors

In this paper an automated procedure for prediction of microwave transistor noise parameters versus temperature is presented. It is based on an improved Pospieszalski's noise model. In order to avoid extraction of device noise model equivalent circuit parameters (ECP) from the measured scattering and noise parameters for each operating temperature, an artificial neural network is introduced for modeling of the ECP temperature dependence. Therefore, it is necessary to acquire the measured data and extract the ECP only for several operating temperatures used for the network training. Once the network is trained and assigned to the considered noise model, the device noise parameters are easily obtained for each temperature from the operating range. It is done without changes in the network structure and without the need for time consuming and complex measurements and optimiztions.     

A discrete fractional Gabor expansion for multi-component signals

Gabor expansion is widely used to represent the time-varying frequency content of non-stationary signals. Recently, new representations are presented on a general non-rectangular time–frequency grid. In this paper, we present a closed-form, discrete fractional Gabor expansion and show that it can be used to estimate a high resolution time–frequency representation for multi-component signals. The proposed expansion uses the discrete fractional Fourier kernel and generates a parallelogram-shaped time–frequency plane tiling. Completeness and biorthogonality conditions of the new expansion are derived. We also present a search algorithm to obtain optimal analysis fraction orders for the compact representation of multi-component signals.     

Impact of electroplated copper thickness on copper CMP and Cu/Coral™ BEOL integration

A study was carried out to establish the impact of electrochemical plated (ECP) Cu thickness on the effect of dishing during Cu chemical mechanical planarization and the electrical and reliability performance of 0.13 μm Cu/Coral devices. The roughness of Cu films at the wafer edge was found to increase with increasing film thickness while it remained constant at the wafer centre. This resulted in different Cu grain morphology across the wafers. The reduction in sheet resistance (R_s) for the Cu film after annealing, as well as the as-deposited and post annealed film stresses were also found to be dependent on the ECP Cu thickness. As the thickness increased, the R_s reduction increased while the as-deposited and post annealed film stresses decreased. The different ECP Cu thickness did not show any significant difference in the amount of Cu dishing at the centre of the wafers. However, at the wafer edge, the Cu dishing amount was found to be significantly affected by the Cu thickness in which the amount of dishing increased as the thickness increased. The via chain, Kelvin via, M1 line and M2 line resistances also showed a strong dependence on the ECP Cu thickness. The thinnest Cu film of 0.7 μm gave the lowest results with the tightest spread for the four resistances tested. For the via chain and M1 line resistance, it was followed by the 1.0 μm Cu film and the 1.3 μm film yielded the worst data. In the case of Kelvin via and M2 line resistance, the thicker plated Cu films gave similar worse results. All the electrical results showed good coincidence with the Cu dishing data. The voltage ramp (v-ramp) data showed no significant difference in the electrical field leading to dielectric breakdown at both M1 and M2 lines for all the three types of ECP Cu thickness split.     

Measurements of low angle fading in the Canadian arctic

In July 1974, an experiment was conducted at Eureka, Canada (80° N, 86° W), to measure the tropospheric fading of satellite signals at 4 and 6 GHz. At Eureka, the 4.6 m antenna was located on a hill 250 m above sea level providing a clear path at an elevation angle of 1° to the Anik II satellite. The 4 GHz downlink signal strength was recorded at Eureka. Fading of the 6 GHz uplink signal from Eureka was measured at the Communications Research Centre, Ottawa. The uplink and downlink fading contributions for the entire experimental period are nearly identical, indicating that the fading distributions are essentially frequencyindependent over the 4–6 GHz range. For the 18 days period of the experiment, the link margins are 10.8 dB and 20.3 dB for 99 % and 99.9 % reliability, respectively. For the worst twohour period, the margins are 18 dB and 28 dB, corresponding to those for a Rayleigh distribution. No marked diurnal effect is discernible. Distributions of the fade durations indicate, for example, that 90 % of all fades exceeding 6 dB do not exceed 36 seconds duration. Although fading at 4 GHz is always accompanied by fading at 6 GHz, their correlation is sometimes poor, yielding correlation coefficients as low as 0.34. The amplitude correlation of two 6 GHz signals separated by up to 10 MHz always exceeds 0.90, indicating minimal amplitude distortion across the band. The implications of these results on the design of a satellite link are discussed.     

Laser ultrasonic study of porous silicon layers

Propagation of ultrasonic signals induced by nanosecond laser pulses in porous silicon (por-Si) is considered from both the theoretical and the experimental viewpoints. The experimental samples are por-Si layers with 5-to 40-µm thickness and porosity of 50–75%; these layers were formed on a single-crystal silicon substrate by electrochemical etching. It is shown that the suggested ultrasonic laser method allows both the thickness and the porosity of a layer to be determined with the respective accuracies of no worse than 1 µm and 5%.     

采用扫描电镜的ECP技术分析人工合成金刚石晶体中的晶体缺陷

本文应用扫描电镜的ＥＣＰ技术对人造金刚石晶体表面的位错密度，进行了实验分析，并同位错蚀坑分析技术的测量结果进行了比较，结果表明，如采用临界束流强度作为描述ＥＣＰ本征衬度的参数，则它同位错密度间存在明显定量的数学关系，因此上述临界束流强度可用来评价晶体中位错密度的相对变化。     

Unambiguous determination of fine structures in multicomponent time-varying signals

When analysed with simple methods, multicomponent time-varying signals may present, in the frequency-time plane, patterns which look similar even when the original structures of the signals are completely different. The authors study here the f–t patterns which are obtained when analysing two different types of signals. Type I signals are closely adjacent gliding tones (whose frequency varies linearly with time). Type II signals consist of a series of monochromatic lines of finite duration, slightly spaced in time. Depending on the bandwidth of the analysing filter B, different patterns are obtained, which they discuss as a function of B and of the intrinsic properties of the original signal. A method is proposed for distinguishing unambiguously between the two types of signals. A numerical simulation is done in order to demonstrate the validity of the theory.     

Life-threatening arrhythmia verification in ICU patients using the joint cardiovascular dynamical model and a Bayesian filter

In this paper, a novel nonlinear joint dynamical model is presented, which is based on a set of coupled ordinary differential equations of motion and a Gaussian mixture model representation of pulsatile cardiovascular (CV) signals. In the proposed framework, the joint interdependences of CV signals are incorporated by assuming a unique angular frequency that controls the limit cycle of the heart rate. Moreover, the time consequence of CV signals is controlled by the same phase parameter that results in the space dimensionality reduction. These joint equations together with linear assignments to observation are further used in the Kalman filter structure for estimation and tracking. Moreover, we propose a measure of signal fidelity by monitoring the covariance matrix of the innovation signals throughout the filtering procedure. Five categories of life-threatening arrhythmias were verified by simultaneously tracking the signal fidelity and the polar representation of the CV signal estimations. We analyzed data from Physiobank multiparameter databases (MIMIC I and II). Performance evaluation results demonstrated that the sensitivity of the detection ranges over 93.50% and 100.00%. In particular, the addition of more CV signals improved the positive predictivity of the proposed method to 99.27% for the total arrhythmic types. The method was also used for false arrhythmia suppression issued by ICU monitors, with an overall false suppression rate reduced from 42.3% to 9.9%. In addition, false critical ECG arrhythmia alarm rates were found to be, on average, 42.3%, with individual rates varying between 16.7% and 86.5%. The results illustrate that the method can contribute to, and enhance the performance of clinical life-threatening arrhythmia detection.     

DC cancellation in the single-bit domain using ternary filtering

A structure for single-bit DC blocking is presented. This type of DC blocker is useful in practice to improve the stability and dynamic range of single-bit systems. The DC blocker is essentially a ternary filtering structure whose input and output are both assumed to be sigma–delta modulated bitstreams. Two techniques have been utilised to design the ternary filter to allow for implementation and performance comparison. Performance is tested for different kinds of single-bit format input signals, including sinusoidal, FM and AM–FM signals. The proposed DC blocker contains no multipliers and can easily be implemented with FPGA technology.     

Ionospheric distortions of high-frequency pseudorandom signals

The ionospheric propagation of shortwave signals with pseudorandom frequency shift are considered with allowance for their coherent and incoherent reception. The frequency ranges within which 1D propagation is realized over ionospheric radio links 2–8 Mm long are investigated, and the dispersion characteristics of these propagation channels are determined. The effect of the dispersion distortions on the reception of pseudorandom signals is investigated, and the maximal permissible signal parameters are estimated.