Tunable RF excited waveguide CO-2 laser with two unequal long channels

Presents a waveguide CO 2 laser with two unequal long channels excited by radio frequency (RF) which has more than 30 laser lines from a long channel of 400 mm with grating, and 3 laser lines from a short channel of 200 mm by PZT.

Device-Free Through-the-Wall Activity Recognition Using Bi-Directional Long Short-Term Memory and WiFi Channel State Information

Activity recognition plays a key role in health management and security.Traditional approaches are based on vision or wearables,which only work under the line of sight(LOS)or require the targets to carry dedicated devices.As human bodies and their movements have influences on WiFi propagation,this paper proposes the recognition of human activities by analyzing the channel state information(CSI)from the WiFi physical layer.The method requires only the commodity:WiFi transmitters and receivers that can operate through a wall,under LOS and non-line of sight(NLOS),while the targets are not required to carry dedicated devices.After collecting CSI,the discrete wavelet transform is applied to reduce the noise,followed by outlier detection based on the local outlier factor to extract the activity segment.Activity recognition is fulfilled by using the bi-directional long short-term memory that takes the sequential features into consideration.Experiments in through-the-wall environments achieve recognition accuracy>95%for six common activities,such as standing up,squatting down,walking,running,jumping,and falling,outperforming existing work in this field.

Effect of Calcium-Channel Antagonist on Repolarization Heterogeneity of Ventricular Myocardium in an in Vitro Rabbit Model of Long QT Syndrome

Intracellular Ca2＋ and Ca2＋-dependent signaling molecule play an essential role in the genesis of long-QT （LQT） syndrome-related ventricular arrhythmias. The effect of calcium-channel antagonist verapamil on repolarization heterogeneity of ventricular myocardium was assessed in an in vitro rabbit model of LQT syndrome. By using the monophasic action potential （MAP） recording technique, MAPs of epicardium, mid-myocardium and endocardium were simultaneously recorded by specially designed plunge-needle electrodes across the left ventricular free wall in rabbit hearts purfused by Langendorff method with standard Tyrode＇s solution. Bradycardia was induced by com- plete ablation of atrioventricular node. A catheter was introduced into the right ventricle to pace at the cycle lengths （CLs） of 1500, 1000, and 500 ms, successively. Quinidine （2 μmol/L） prolonged QT interval and ventricular MAP duration （MAPD）, and increased transmural dispersion of repolarization （TDR） in a reverse rate-dependent fashion in isolated rabbit heart. No polymorphic ventricular tachycardias were induced under this condition. The effective free therapeutic plasma concentrations of verapamil （0.01--0.05μmol/L） used in this experiment had no effect on quinidine-induced changes of QT interval, MAPD and TDR. This study demonstrated that, in this model of LQT syndrome, blockade of calcium-channel with verapmil had no effect on quinidine-induced changes of repolatiation heterogeneity of ventricular myocardium.

A Practical Regular LDPC Coded Scheme for Physical-Layer Information Security

In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from eavesdropping.To this end,we first propose a punctured LDPC coded scheme,where the information bits in a codeword are punctured and only the parity check bits are transmitted to the receiver.We further propose a notion of check node type distribution and derive multi-edge type extrinsic information transfer functions to estimate the security performance,instead of the well-known weak metric bit error rate.We optimize the check node type distribution in terms of the signal-to-noise ratio(SNR)gap and modify the progressive edge growth algorithm to design finite-length codes.Numerical results show that our proposed scheme can achieve a lower computational complexity and a smaller security gap,compared to the existing scrambling and puncturing schemes.

A Dual-Channel Secure Transmission Scheme for Internet-Based Networked Control Systems

Two significant issues in Internet-based networked control systems （ INCSs）, transport performance of different protocols and security breach from Internet side, are investigated. First, for improving the performance of data transmission, user datagram protocol （UDP） is adopted as the main stand for controllers and plants using INCSs. Second, a dual-channel secure transmission scheme （DCSTS）based on data transmission characteristics of INCSs is proposed, in which a raw UDP channel and a secure TCP （transmission control protocol） connection making use of SSL/TLS （secure sockets layer/transport layer security） are included. Further, a networked control protocol （NCP） at application layer for supporting DCSTS between the controllers and plants in INCSs is designed, and it also aims at providing a universal communication mechanism for interoperability of devices among the networked control laboratories in Beijing Institute of Technology of China, Central South University of China and Tokyo University of Technology of Japan. By means of a networked single-degree-of-free- dom robot arm, an INCS under the new protocol and security environment is created. Compared with systems such as IPSec or SSL/TLS, which may cause more than 91% network throughput deduction, the new DCSTS protocol may yield results ten times better, being just 5.67%.

Dual Channel with Involution for Long-Tailed Visual Recognition

With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Although they can significantly promote the classifier learning of deep networks, they will unexpectedly impair the representative ability of the learned deep features to a certain extent. Therefore, this paper proposes a dual-channel learning algorithm with involution neural networks (DC-Invo) to take care of representation learning and classifier learning concurrently. In this work, the most important thing is to combine ResNet and involution to obtain higher classification accuracy because of involution’s wider coverage in the spatial dimension. The paper conducted extensive experiments on several benchmark vision tasks including Cifar-LT, Imagenet-LT, and Places-LT, showing that DC-Invo is able to achieve significant performance gained on long-tailed datasets.

Coding Scheme for Ka-Band Fixed Satellite Communication System

The performance analysis and simulation of coding schemes based on the modeling Ka band fixed satellite channel have been presented. The results indicate that concatenated codes with large inner interleaving depth have good performance and high spectrum efficiency. The studies also show that simple block interleaving is very effective in combating the slow frequency nonselective fading of Ka band.

Iterative receivers for SFBC-OFDM systems with adaptive training scheme

This paper considers the design of iterative receivers for space-frequencyblock-coded orthogonal frequency division multiplexing (SFBC-OFDM) systems in unknown wirelessdispersive fading channels. An iterative joint channel estimation and symbol detection algorithm isderived. In the algorithm, the channel estimator performs alternately in two modes. During thetraining mode, the channel state information (CSI) is obtained by a discrete-Fourier-transform-basedchannel estimator and the noise variance and covariance matrix of the channel response is estimatedby the proposed method. In the data transmission mode, the CSI and transmitted data is obtainediteratively. In order to suppress the error propagation caused by a random error in identifyingsymbols, a simple error propagation detection criterion is proposed and an adaptive training schemeis applied to suppress the error propagation. Both theoretical analysis and simulation results showthat this algorithm gives better bit-error-rate performance and saves the overhead of OFDM systems.

MODELING AND SIMULATION OF E1784K MUTATION AND SODIUM IONIC CHANNEL DISEASES

In the clinical reports, the E1784K mutation in SCN5A is recognized as a phenotypic overlap between the long QT syndrome （LQT3） and the Brugada syndrome （BrS） in the characteristics of electrocardiograms （ECGs） since the mutation can influence sodium channel functions. However it is still unclear if the E1784K mutation-induced sodium ionic channel alterations account for the overlap at tissue level. Thsu, a detailed computational model is developed to underpin the functional impacts of the E1784K mutation on the action potential （AP）, the effective refractory period （ERP） and the abnormal ECG. Simulation results stlggest＇that the E1784K mutation-induced sodium channel alterations are insufficient to produce the phenotypic overlap between LQT3 and BrS, and the overlap may arise from the complicated effects of the E1784K mutation-induced changes in sodium channel currents with an increase of the transient outward current ITo or a decrease of the L-type calcium current ICaL .

Characterization of three-dimensional channel reservoirs using ensemble Kalman filter assisted by principal component analysis

Ensemble-based analyses are useful to compare equiprobable scenarios of the reservoir models.However,they require a large suite of reservoir models to cover high uncertainty in heterogeneous and complex reservoir models.For stable convergence in ensemble Kalman filter(EnKF),increasing ensemble size can be one of the solutions,but it causes high computational cost in large-scale reservoir systems.In this paper,we propose a preprocessing of good initial model selection to reduce the ensemble size,and then,EnKF is utilized to predict production performances stochastically.In the model selection scheme,representative models are chosen by using principal component analysis(PCA)and clustering analysis.The dimension of initial models is reduced using PCA,and the reduced models are grouped by clustering.Then,we choose and simulate representative models from the cluster groups to compare errors of production predictions with historical observation data.One representative model with the minimum error is considered as the best model,and we use the ensemble members near the best model in the cluster plane for applying EnKF.We demonstrate the proposed scheme for two 3D models that EnKF provides reliable assimilation results with much reduced computation time.

Direct simulation of MHD flows in dual-coolant liquid metal fusion blanket using a consistent and conservative scheme

Direct simulation of 3-D MHD(magnetohydrodynamics) flows in liquid metal fusion blanket with flow channel insert(FCI) has been conducted.Two kinds of pressure equilibrium slot (PES) in FCI,which are used to balance the pressure difference between the inside and outside of FCI,are considered with a slot in Hartmann wall or a slot in side wall,respectively.The velocity and pressure distribution of FCI made of SiC/SiC_f are numerically studied to illustrate the 3-D MHD flow effects,which clearly show that the flows in fusion blanket with FCI are typical three-dimensional issues and the assumption of 2-D fully developed flows is not the real physical problem of the MHD flows in dual-coolant liquid metal fusion blanket.The optimum opening location of PES has been analyzed based on the 3-D pressure and velocity distributions.

Deep Learning-Based Symbol Detection for Time-Varying Nonstationary Channels

The highly dynamic channel(HDC)in an extremely dynamic environment mainly has fast timevarying nonstationary characteristics.In this article,we focus on the most difficult HDC case,where the channel coherence time is less than the symbol period.To this end,we propose a symbol detector based on a long short-term memory(LSTM)neural network.Taking the sampling sequence of each received symbol as the LSTM unit's input data has the advantage of making full use of received information to obtain better performance.In addition,using the basic expansion model(BEM)as the preprocessing unit significantly reduces the number of neural network parameters.Finally,the simulation part uses the highly dynamic plasma sheath channel(HDPSC)data measured from shock tube experiments.The results show that the proposed BEM-LSTM-based detector has better performance and does not require channel estimation or channel model information.

Channel characteristics analysis of train-to-train wireless communication

Train-to-train(T2T)communication can provide protection for existing train-to-ground private network communication,and its channel characteristics directly affect the application of upper-layer communication technologies.In this study,based on the spatial distribution structure of railway operation scenarios and Fresnel zone theory,we propose a frequency allocation scheme for direct communication between tracking trains in flatland and long straight tunnel scenario.Then we use the estimation method of radio wave attenuation caused by rainfall to analyze the large-scale path loss fading of multi-band wireless channels.Furthermore,we derive the calculation equation of max Doppler frequency shift suitable for T2T communication and describe the multipath wave in the tunnel by ray tracing method to analyze small-scale fading.Simulation analysis shows that the Doppler shift value of T2T communication low frequency band is significantly lower than the frequency shift value of the train-to-ground communication under the same speed conditions.

Channel Estimation and Data Transmission in Massive MIMO TDD Systems

This paper mainly elaborates the studies of channel estimation and downlink data transmission in Massive MIMO. As there are different types of interference in single-cell and multi-cell systems, this paper establishes different models for them separately. In terms of uplink training, for getting channel state information, we introduce LS and MMSE channel estimation algorithms and make a comparison between them. At the same time, the problem of pilot contamination is solved by cell classification and pilot identification. Next, this paper defines mathematical models for downlink data transmission. We use pre-coding methods (including Zero-forcing and Maximal Ratio Combining schemes) and optimize power distribution to improve channel capacity and transmission rate. Furthermore, this paper provides numerical results to show the simulation performance in both single-cell and multi-cell systems and extends to prospects in the future.

Technology for long cable erection of a thousand-meter scale cable-stayed bridge

In the background of the construction of Sutong Yangtze River Bridge(short as Sutong Bridge),the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced.Some key construction techniques,such as outspreading cable on deck,installing cable at pylon,pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.

Gas-kinetic numerical schemes for one- and two-dimensional inner flows

Several kinds of explicit and implicit finite-difference schemes directly solving the discretized velocity distribution functions are designed with precision of different orders by analyzing the inner characteristics of the gas-kinetic numerical algorithm for Boltzmann model equation. The peculiar flow phenomena and mechanism from various flow regimes are revealed in the numerical simulations of the unsteady Sod shock-tube problems and the two-dimensional channel flows with different Knudsen numbers. The numerical remainder-effects of the difference schemes are investigated aad analyzed based on the computed results. The ways of improving the computational efficiency of the gaskinetic numerical method and the computing principles of difference discretization are discussed.

A novel mutation—L539fs/47 of hERG in a Chinese long QT syndrome family

Objective To identify the mutation of human ether-a-go-go-related gene(hERG)and analyze the clinical characteristics of a Chinese family with long ST syndrome(LQTS).Methods The electrocardiogram and DNA samples were obtained from a Chinese LQTS family of 26 members.Genotype was performed with polymorphic short tandem repeat(STR)markers at the known LQT1,LQT2,and LQT3 loci.SSCP analysis was used to find aberrant conformers.hERG mutation was confirmed by cloning and sequencing.Results Three gene carriers were linked to chromosome 7q35-36,where the potassium channel gene hERG was encoded.A 19-base pair deletion was identified.The mutation was located at nucleotide position 1 619-1 637 between transmembrane domains S4 and S5.Furthermore,A1692G polymorphism was found both in the normal control and patients.Conclusion A novel 19 bp deletion mutation of hERG is identified in a Chinese family.All gene carriers are demonstrated to be typical LQT2 ECG phenotype.

Nonstandard Numerical Schemes for a Linear Stochastic Oscillator with Additive Noise

In order to simulate a linear stochastic oscillator with additive noise,improved nonstandard optimal(INSOPT) schemes are derived utilizing the nonstandard finite difference(NSFD)technique and the improvement technique.These proposed schemes reproduce long time features of the oscillator solution exactly.Their abilities in preserving the symplecticity,the linear growth property of the second moment and the oscillation property of the solution of the stochastic oscillator system on long time interval are studied.It can be shown that the component { x_n}_(n≥1) of the INSOPT schemes switch signs infinitely many times as n →∞,almost surely.Further,the mean-square convergence order of 1 is obtained for these INSOPT schemes.Finally,numerical experiments illustrate intuitively the results obtained in this paper.

Live Video Services Using Fast Broadcasting Scheme

The Fast Broadcasting scheme is one of the simplest schemes that provide video services. In this scheme, the video is divided into equal-sized segments depending upon the bandwidth allocated by the video server. If the video length is not known, then this scheme cannot be applied as the number of video segments cannot be determined. In a live video wherein the video size is unknown, especially the ending time of the live broadcast, e.g., cricket match, this scheme cannot be applied. In this paper, we propose a model that helps the Fast Broadcasting scheme to support live video broadcasting. The basic architecture of the system consists of a live system with one video channel that broadcasts the live video and a video server that broadcasts the already broadcast live video to users.

ZD7288, a selective hyperpolarization-activated cyclic nucleotide-gated channel blocker, inhibits hippocampal synaptic plasticity

The selective hyperpolarization-activated cyclic nucleotide-gated（HCN） channel blocker 4-（N-ethyl-N-phenylamino）-1,2-dimethyl-6-（methylamino） pyrimidinium chloride（ZD7288） blocks the induction of long-term potentiation in the perforant path-CA3 region in rat hippocampus in vivo. To explore the mechanisms underlying the action of ZD7288, we recorded excitatory postsynaptic potentials in perforant path-CA3 synapses in male Sprague-Dawley rats. We measured glutamate content in the hippocampus and in cultured hippocampal neurons using high performance liquid chromatography, and determined intracellular Ca2＋ concentration（[Ca2＋]i） using Fura-2. ZD7288 inhibited the induction and maintenance of long-term potentiation, and these effects were mirrored by the nonspecific HCN channel blocker cesium. ZD7288 also decreased glutamate release in hippocampal tissue and in cultured hippocampal neurons. Furthermore, ZD7288 attenuated glutamate-induced rises in [Ca2＋]i in a concentration-dependent manner and reversed 8-Br-c AMP-mediated facilitation of these glutamate-induced [Ca2＋]i rises. Our results suggest that ZD7288 inhibits hippocampal synaptic plasticity both glutamate release and resultant [Ca2＋]i increases in rat hippocampal neurons.