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An interesting hydrogen (H2) gas sensor, synthesized by an indium oxide (In2O3) layer and evaporated palladium (Pd) nanoparticles (NPs), is manufactured and studied. The utilized Pd NPs essentially enhance the surface area/volume (${S}_{A}/{V})$ ratio and catalytic reactivity of the Pd metal. Energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), high-resolution scanning electron microscopy (HRSEM), and TEM were used to investigate the relevant material behaviors of the proposed Pd NP/In2O3 sensor device. The sensing mechanism is explicated in this study. A very high-sensing response of 5243 under 1% H2/air gas with a response time of 12 s and an extremely low-detecting content of 100 ppb H2/air were obtained at the optimal operating temperature of 225 °C. In addition, excellent selectivity toward hydrogen gas is observed for the studied device. The proposed sensor also shows advantages of simple structure, low-cost, and relatively easy fabrication process. [ABSTRACT FROM AUTHOR]

The nonlinear effects in optical resonators give a promise for the generation of new laser sources. Here, a whispering gallery mode(WGM) micro-rod resonator is fabricated and the mechanism of transmission between Kerr comb to Raman comb is investigated by experimental results and amended Lugiato-Lefever equation(LLE) model. We show that, numerically and experimentally, the WGM resonator-based optical frequency comb can be selectively accessed from Kerr comb state to Kerr-Raman state via pump and detuning controlling. When the detuning is initially set at red detuning, by simply increasing the pump power, the comb state can lock to the stable Raman soliton comb. This indicates the Raman soliton comb is easier to generate compared to the Kerr soliton comb in silica-based WGM resonator. We wish the experimental results demonstrated here can be used for broadband comb applications. [ABSTRACT FROM AUTHOR]

This communication presents the design of a wideband circularly polarized (CP) antenna array based on sequential rotation (SR) technique that is excited by a substrate integrated coaxial line (SICL) with mature and stable processing technology for millimeter-wave (mm-wave) applications. Initially, the influence of the amplitude and phase errors of the feeding network on the axial ratio of the CP array is analyzed, and the detailed design scheme of the wideband CP array based on SR technology is summarized, which can be used to design SR CP array with wide bandwidth and high polarization purity. Then, an SICL-fed $4 \times 4$ CP array working in the mm-wave band that is composed of two substrate layers and a bonding film layer is designed. The radiation element is processed with a larger chamfering, which can realize elliptically polarized radiation in a broadband range, and the impedance bandwidth is significantly expanded relative to the working state of linearly polarized and CP, which has a significant impact on the final array working bandwidth enhancement. The feeding network and radiation elements are directly connected in the same plane. Finally, the proposed antenna is processed and measured to verify the theory and design scheme in this communication. Over the frequency range of 25.0–34.0 GHz, the measured 1.5 dB axial ratio bandwidth of the fabricated prototype is 30.5%, and the return losses are less than −10 dB. The maximum measured peak gain is 16.5 dBi. [ABSTRACT FROM AUTHOR]

Mining the relationship structures among the investors plays a vital role in promoting economic development as well as preventing financial risks, especially in the context of big data. This article proposes fast networking approaches from investment big data to explore three underlying structures, namely, investment pedigrees, investment groups, and structural holes. Inspired by disjoint sets and path compression, we first present a pedigree classification algorithm to identify investment pedigrees. Second, through introducing a pruning strategy and a data structure termed as “2-tuple list,” we develop a novel linear-time structure mining algorithm in network (SMAN) for investigating investment groups and structural holes from the investment pedigree. Finally, we show that our SMAN has higher clustering accuracy and efficiency than other existing algorithms on a variety of real-world tasks in terms of normalized mutual information (NMI) values. Our method is particularly well suited for mining the underlying structures from investment big data. [ABSTRACT FROM AUTHOR]

Influence analysis aims at detecting influential vertices in networks and utilizing them in cost-effective business strategies. Influence analysis in large-scale networks is a key technique in many important applications ranging from viral marketing and online advertisement to recommender systems, and thus has attracted great interest from both academia and industry. Early investigations on influence analysis often assume static networks. However, it is well recognized that real networks like social networks and the web network are not static but evolve rapidly over time. Thus, to make the results of influence analysis in real networks up-to-date, we have to take network evolution into consideration. Incorporating evolution of networks into influence analysis raises many new challenges, since an evolving network often updates at a fast rate and, except for the network owner, the evolution is usually even not entirely known to people. In this survey, we provide an overview on recent research in influence analysis in evolving networks, which has not been systematically reviewed in literature. We first revisit mathematical models of evolving networks and commonly used influence models. Then, we review recent research in five major tasks of evolving network influence analysis. We also discuss some future directions to explore. [ABSTRACT FROM AUTHOR]

Pure shift techniques, as one of the rapidly developing frontiers in nuclear magnetic resonance (NMR) fields, can significantly enhance the resolution of NMR spectrum with a removal of splittings induced by scalar couplings. However, periodic artifacts due to residual scalar couplings during acquisition arise on all direct pure shift spectra, causing severe problems in analysis of complicated samples. Herein, we construct a signal model for the pure shift data and discuss the mechanism of periodic artifacts. Then, based on constraints on the low-rank property of pure shift NMR data, a subsequent artifact-suppression method is proposed to reconstruct a clean pure shift spectrum. With the proposed method, clean $^{\mathbf {1}}\text{H}$ pure shift spectrum can be obtained from only one experiment, greatly accelerating the experiment time while remaining the accuracy of the quantitative measurement. Experiments on a synthesis NMR signal, a complex sample of quinine with pseudo 2-D acquisition, and a medicine sample of azithromycin with 1-D acquisition are carried out to evaluate the feasibility and universality of the proposed method for different experimental techniques. Both the theoretical analysis and experimental results demonstrate the effectiveness of the proposed method for periodic artifacts suppression on complex samples and its potential for practical applications. [ABSTRACT FROM AUTHOR]

Due to the excellent electromagnetic properties of superconductor materials, superconducting generators have higher efficiency, lower weight and volume than traditional rotating machines. However, it is difficult to simulate the electromagnetic behavior in the superconducting generator due to the nonlinear E–J relationship. A numerical model based on the T–A formulation and moving mesh method is adopted to simulate the superconducting rotating machine, and the electromagnetic and mechanical behaviors of the superconducting rotating machine are investigated. The fully superconducting generator investigated in this article is radial type, which consists of field windings and armature windings made from YBa2Cu3O7−Δ (YBCO) superconducting race-track coils. The anisotropic field-dependent critical current density and the E–J power law relationship are considered in our model. The “virtual tape” model is introduced to calculate the induced current in the T–A formulation. The numerical results are obtained by the finite element method. The electromagnetic results calculated by our model are compared with results from the H–A formulation. The ac losses and stress distributions in superconducting coils are presented based on the T–A formulation. The results show that the body force and stress are periodic, and the stress will concentrate on the boundary of the coil. The magnetic field in the rotor is larger than that in the stator, and the field windings suffer greater body force and stress than the armature windings. This model has acceptable relative error with the H–A model for the time saved following T–A approach and relevance to mechanical calculations. Thus, this model can aid the design of superconducting rotating machines. [ABSTRACT FROM AUTHOR]

We investigated high-order harmonic generation in molecules N2 and C6H6 irradiated by bichromatic counter-rotating circularly polarized laser pulses by using time-dependent density-functional theory methods. It is found that $3N$ ($N$ is an integer) order harmonics in C6H6 disappear. Whereas, $N$ order harmonics are obtained in N2. Analysis of the high harmonic generated from individual electronic orbital of the molecule, shows that, the characteristics of harmonic spectra are determined by the spatial distribution of electronic orbits. Moreover, effects of molecular orientation on harmonic emission are also presented. [ABSTRACT FROM AUTHOR]

A wideband traveling-wave circularly polarized (CP) antenna printed on a single-layer PCB for millimeter-wave (MM-Wave) applications is presented in this communication. The proposed antenna radiates the CP wave on the basis of the principle similar to the classical endfire-mode helical antenna. The proposed antenna is terminated with an absorber to realize traveling-wave radiation. The traveling-wave working mechanism causes the proposed antenna to have a frequency scanning function and higher stability compared with resonant antennas. Curved microstrip transmission lines are adopted as the CP radiation elements; the whole array antenna is etched on a single-layer substrate. A prototype operating at 30 GHz is fabricated and measured. The radiation beam of the proposed antenna scans from − 14.5° (28 GHz) to +22.5° (34 GHz), the axial ratios are lower than 3 dB, and the measured gains show a maximum value of 21.9 dBi at 33 GHz and a minimum value of 20.3 dBi at 28 GHz. The measured $| \text {S}_{11} |$ and $| \text {S}_{21} |$ are lower than −10 and −16 dB, respectively, in the frequencies mentioned above. [ABSTRACT FROM AUTHOR]

A cooperative design of the advanced time-modulated array (TMA) and the retrodirective (RD) array is introduced to act as a transmitting array for multiuser wireless power transmission (WPT) applications. The conventional rectangular-pulse based TMA is lack of harmonic beamforming flexibility limited by its frequency spectral properties. By preprocessing the rectangular pulses with the sinusoid-based control signal, harmonic beams are independently steerable. The proposed array is enabled with self-phasing capability by taking advantage of the RD technique. Besides, to avoid the unexploited radiation caused by unscannable fundamental beam and specular harmonic beams, the single sideband (SSB) modulator is utilized to enable the transmitting array with high-efficiency beamforming capacity. The numerical results verify that the presented array performs well in various charging scenarios, which brings a highly potential insight for far-field WPT. [ABSTRACT FROM AUTHOR]

Exponentially decaying sinusoidal signal model is generally applied in a wide range of engineering and research fields. In order to analyze the signal components quantitatively, we need to extract the important parameters, i.e., amplitudes, frequencies, and damping factors, from the signals. In some practical applications, we can obtain multiple signals from multiple sensors or with multiple procedures. In such a way, the acquired signals are composed of similar sources or components but with different intensities. How to separate different sources and estimate the intensities of each source within the signals is essential for further analysis. In this paper, we separated different sources within two mixtures by estimating the relative intensities of the sources within mixtures. First, to evaluate a “clean” separation result, we proposed a minimum rank criterion, i.e., the Hankel matrices of the isolated sources should have the minimum rank, which corresponds to a simplified signal composition. Second, in order to minimize the rank of the Hankel matrices, we reformulated the objective function as a generalized eigenvalue decomposition problem, which can be solved based on the minimum perturbation theory. By this method, we can detect the number and intensities of common harmonic components within two mixtures, and isolate two complicated source signals with highly overlapped spectra from the mixtures. The proposed method can be applied for signal simplification or component quantification in a wide range of areas, such as biomedical or electrical engineering, where the signals are usually modeled as a sum of sinusoidal components. [ABSTRACT FROM AUTHOR]

This communication presents a dual-polarized series-fed array antenna with 30° beam-pointing for millimeter-wave (MM-Wave) applications. The 45° and −45° polarized subarrays share the aperture in an interdigital shape. The spacing between subarrays with the same polarization orientation is set to $0.56\lambda _{0}$ through the use of narrower T-type folded substrate integrated waveguide (TFSIW) instead of substrate integrated waveguide (SIW). The substrate integrated coaxial line (SICL) is adopted to design the array feeding network. To validate the proposed design, a $4 \times 6$ (single polarization) dual-polarized array antenna operating at 28 GHz with 30° beam-pointing is fabricated. Based on the measurement, the return losses are lower than −10 dB from 27.5 to 28.5 GHz, the isolations between the two polarization ports are higher than 30.0 dB in the frequencies mentioned above, the maximum gain at the center frequency is 15.7 dBi, and the cross-polarization levels are lower than −18.5 dB. The proposed antenna only needs one-step processing with the standard PCB technology without additional stitching assembly. Simulated and measured results of the proposed antennas were compared. [ABSTRACT FROM AUTHOR]

This paper presents the design of dual circularly polarized (CP) series-fed arrays based on the sequential rotation (SR) technique with uniform radiation elements. The radiation elements and feeding network used in the array are uniform, which leads to the possibility of dual-CP radiation by series-fed SR arrays. Meanwhile, the elements radiate unequal powers due to this arrangement. The relationship between the axial ratio and four key parameters of the array is derived and thoroughly discussed. Good polarization purity and port isolation can be realized by optimizing these parameters. A dual-CP array working at 10 GHz is designed with the help of the analysis. The experimental results show that the proposed antenna has good properties. [ABSTRACT FROM AUTHOR]

In a social network, even about the same information the excitement between different users are different. If we want to spread a piece of new information and maximize the expected total amount of excitement, which seed users should we choose? This problem indeed is substantially different from the renowned influence maximization problem and cannot be tackled using the existing approaches. In this paper, motivated by the demand in a few interesting applications, we model the novel problem of activity maximization, and tackle the problem systematically. We first analyze the complexity and the approximability of the problem. We develop an upper bound and a lower bound that are submodular so that the Sandwich framework can be applied. We then devise a polling-based randomized algorithm that guarantees a data dependent approximation factor. Our experiments on four real data sets clearly verify the effectiveness and scalability of our method, as well as the advantage of our method against the other heuristic methods. [ABSTRACT FROM PUBLISHER]

In this paper, we tackle a challenging problem inherent in a series of applications: tracking the influential nodes in dynamic networks. Specifically, we model a dynamic network as a stream of edge weight updates. This general model embraces many practical scenarios as special cases, such as edge and node insertions, deletions as well as evolving weighted graphs. Under the popularly adopted linear threshold model and independent cascade model, we consider two essential versions of the problem: finding the nodes whose influences passing a user specified threshold and finding the top-$k$ most influential nodes. Our key idea is to use the polling-based methods and maintain a sample of random RR sets so that we can approximate the influence of nodes with provable quality guarantees. We develop an efficient algorithm that incrementally updates the sample random RR sets against network changes. We also design methods to determine the proper sample sizes for the two versions of the problem so that we can provide strong quality guarantees and, at the same time, be efficient in both space and time. In addition to the thorough theoretical results, our experimental results on five real network data sets clearly demonstrate the effectiveness and efficiency of our algorithms. [ABSTRACT FROM PUBLISHER]

AC loss has become a key problem for practical applications of high-temperature superconductors. It is well known that mechanical deformation will affect the critical current and ac loss as the superconductor is subjected to the magnetic field or transport current. In this paper, the ac losses in Bi2Cr2Ca2Cu 3O10 (Bi2223)/Ag tapes under bending deformation are investigated. Bi2223 tape consists of Ag matrix and Bi2223 filaments, and the ac losses are generated by transport current and external field. By considering the plastic deformation of Ag matrix and residual strain, the simplified mechanical fracture model is established. Then, the finite element method analysis is used to investigate the relation of critical current and ac loss with bending deformations, and the losses are presented for different transport current and external magnetic field conditions. The influences of filament fracture on the ac loss are discussed for transport current and external magnetic field cases, respectively. [ABSTRACT FROM PUBLISHER]

A slot helix antenna working in Global Positioning System (GPS) L1 and L2 bands is proposed in this paper. Adopting sequential rotation technique, the proposed antenna is equipped with six helix radiation arms and fed by a microstrip line with folded shape. The whole antenna can be built on a full printed circuit board; so, it is easy to process the proposed antenna. The circularly polarized radiation mechanism of a circular array is analyzed in a new perspective to guide the design. A double-faced slot radiation structure is also established for dual-band operation. Additionally, a traveling wave feeding network suitable for the proposed antenna is presented. The experimental results show that the proposed antenna has good properties in GPS L1 and L2 bands. [ABSTRACT FROM PUBLISHER]

Distance estimation based on the received signal strength (RSS) of wireless radio has been extensively studied; however, the estimation accuracy is susceptible to radio propagation conditions, particularly during periods of precipitation. This study performed experiments on the 1.8-GHz band of Global System for Mobile Communications (GSM) networks at Yuan Ze University, Taoyuan, Taiwan, sensing actual radio power signals using mobile phones and recording transmission conditions during various weather events. The aim was to compare RSS performance under dry and wet weather conditions and study the dynamics of distance estimation from theoretical and empirical perspectives. Traditional rain attenuation models have largely discounted the impact of precipitation on GSM signals due to the relatively low frequency band; however, on-site experimental results demonstrated that dynamic weather significantly degrades accuracy in distance estimation. This study employed a typical rain attenuation model and a radio propagation model to evaluate errors in distance estimation under various rain conditions, i.e., heavy rain, extremely heavy rain, torrential rain, and extremely torrential rain, in accordance with the standards set out by the Central Weather Bureau, Taiwan. This study also investigated the RSS attenuation under various wind speeds. The Cramer–Rao lower bound (CRLB) was used as a benchmark for comparison. [ABSTRACT FROM AUTHOR]

In many fields, e.g., ground-penetrating radar and ultra-wideband radiation, a high-pulse-repetition-frequency (PRF) and high-time-base-stability sub-nanosecond pulser is required, and its output waveform should be close to a gaussian pulse. In this article, the transistorized pulser is studied and optimized to improve its output parameters. The printed circuit board circuit parameters of the pulser are first optimized, which is beneficial for the amplitude and the rise time. To improve the time base stability, the collector voltage ramp triggering mode is adopted to replace the conventional base triggering mode for the pulser. For higher PRF, the pulser with the capacitance–transistor parallel structure is immersed in the fluorinert liquid. Moreover, the deficit-charge method is adopted, and small charging capacitances are used in the last few stages to weaken the oscillation in the pulse falling edge. From experimental results, the amplitude of the optimized pulser is 1.35 kV, its rise time is reduced from about 200 to 135 ps, the maximum PRF is improved from 250 to 500 kHz, the pulse jitter is reduced to 22 ps, and the pulse drift is reduced from hundreds of ps/min to 47 ps/min. Meanwhile, the oscillation in its falling edge is greatly suppressed. [ABSTRACT FROM AUTHOR]

System state estimation relies heavily on the measurements. With the advance of sensing technology, the ability to measure is no longer a bottleneck in many systems, and more and more researchers now focus on the rich-information setting, i.e., big data. However, although information never hurts, it does not help unconditionally. How to make the most of it depends on whether we can process the data efficiently. In some systems, the inherent constraint such as the bandwidth and cost makes it necessary to reduce the dimension of the measurement before further processing. The problem that the raw measurements are first preprocessed to reduce size and then used for estimation is addressed in this paper. It is shown that there is a lower bound on the size of the preprocessed data such that if the size is beyond the bound, there exists a closed-form estimator design that the linear minimum mean-square estimation can be obtained. Moreover, we propose an algorithm that is guaranteed to converge to a stationary point to design an estimator in the conditions that the lower bound cannot be reached. Besides convergence, the proposed algorithm guarantees bounded performance loss compared with the global optimal solution under some additional conditions. Finally, simulation results in three different applications are shown to demonstrate the effectiveness of the proposed algorithm. [ABSTRACT FROM PUBLISHER]

Modern IC designs are exposed to a wide range of dynamic variations. Traditionally, a conservative timing guardband is required to guarantee correct operations under the worst-case variation, thus leading to performance degradation. To remove the guardband, resilient circuits are proposed. However, the short-path padding (hold time fixing) problem in resilient circuits is far severer than conventional IC design. Therefore, in this paper, we focus on the short-path padding problem to enable the timing error detection and correction mechanism of resilient circuits. Unlike recent prior work adopts greedy heuristics with a local view, we determine the padding values and locations with a global view. Moreover, we utilize spare cells and a dummy metal to further achieve the derived padding values at physical implementation. Experimental results show that our method is promising to validate timing error-resilient circuits. [ABSTRACT FROM PUBLISHER]

Digital ecosystems (DEs) are based on a large amount of distributed data, and these data are gathered from physical devices, particularly from wireless sensor networks (WSNs). Due to the inherent stringent bandwidth and energy constraints, energy-efficient mechanisms of performance measurement are the key to the proper operation of WSNs and thereby important for the data reliability of DEs. This paper presents a novel algorithm, i.e., Loss Inference based on Passive Measurement (LIPM), to infer WSN link loss performance. The LIPM algorithm passively monitors the application traffic between sensor nodes and the sink (base station), and then uses network tomography technology to infer the network internal performance. Furthermore, contour maps, the well-known representation of data, are first taken into account in WSN loss performance inference, which can help the LIPM algorithm identify lossy areas rapidly. Finally, the algorithm is validated through simulations and exhibits good performance and scalability. [ABSTRACT FROM AUTHOR]

During the very large scale integration design process, a synthesized design is often required to be modified in order to accommodate different goals. To preserve the engineering effort already invested, designers seek small logic structural transformations to achieve these logic restructuring goals. This paper proposes a systematic methodology to devise such transformations automatically. It first presents a simulation-based formulation to approximate sets of pairs of functions to be distinguished and avoid the memory/time explosion issue inherent with the original representation. Then, it uses this new data structure to devise the required transformations dynamically without the need of a static dictionary model. The methodology is applied to both combinational and sequential designs with transformations at a single or multiple locations. An extensive suite of experiments documents the benefits of the proposed methodology when compared to existing practices. [ABSTRACT FROM PUBLISHER]

In this paper, we aim to solve the multiuser multi-input multi-output (MIMO) downlink beamforming problem where one multi-antenna base station broadcasts data to many users. Each user is assigned multiple data streams and has multiple antennas at its receiver. Efficient solutions to the joint transmit-receive beamforming and power allocation problem based on iterative methods are proposed. We adopt the group maximum signal-to-interference-plus-noise-ratio (SINR) filter bank (GSINR-FB) as our beamformer which exploits receiver diversity through cooperation between the data streams of a user. The data streams for each user are subject to an average SINR constraint, which has many important applications in wireless communication systems and serves as a good metric to measure the quality of service (QoS). The GSINR-FB also optimizes the average SINR of its output. Based on the GSINR-FB beamformer, we find an SINR balancing structure for optimal power allocation which simplifies the complicated power allocation problem to a linear one. Simulation results verify the superiority of the proposed algorithms over previous works with approximately the same complexity. [ABSTRACT FROM PUBLISHER]

From microwave and resonant tunneling spectroscopy measurements we independently obtained all device parameters needed to reconstruct the Hamiltonian of an rf-SQUID flux qubit. Energy relaxation of the qubit as a function of flux bias and temperature was investigated experimentally. It is found that the energy relaxation rate at different flux biases scales to a universal temperature dependence. This universal T-dependence of T1 time agrees well with a theoretical model in which the thermal equilibrium population of the excited states is considered. [ABSTRACT FROM AUTHOR]

We study the problem of constructing a data gathering tree over a wireless sensor network in order to minimize the total energy for compressing and transporting information from a set of source nodes to the sink. This problem is crucial for advanced computation-intensive applications, where traditional "maximum" in-network compression may result in significant computation energy. We investigate a tunable data compression technique that enables effective tradeoffs between the computation and communication costs. We derive the optimal compression strategy for a given data gathering tree and then investigate the performance of different tree structures for networks deployed on a grid topology as well as general graphs. Our analytical results pertaining to the grid topology and simulation results pertaining to the general graphs indicate that the performance of a simple greedy approximation to the Minimal Steiner Tree (MST) provides a constant factor approximation for the grid topology and good average performance on the general graphs. Although theoretically, a more complicated randomized algorithm offers a poly-logarithmic performance bound, the simple greedy approximation of MST is attractive for practical implementation. [ABSTRACT FROM AUTHOR]

A novel algorithm for digital infinite-impulse response (IIR) filter design is proposed in this paper. The suggested algorithm is a kind of cooperative coevolutionary genetic algorithm. It considers the magnitude response and the phase response simultaneously and also tries to find the lowest filter order. The structure and the coefficients of the digital IIR filter are coded separately, and they evolve coordinately as two different species, i.e., the control species and the coefficient species. The nondominated sorting genetic algorithm-II is used for the control species to guide the algorithms toward three objectives simultaneously. The simulated annealing is used for the coefficient species to keep the diversity. These two strategies make the cooperative coevolutionary process work effectively. Comparisons with another genetic algorithm-based digital IIR filter design method by numerical experiments show that the suggested algorithm is effective and robust in digital IIR filter design. [ABSTRACT FROM AUTHOR]

Ensemble learning algorithms train multiple component learners and then combine their predictions. In order to generate a strong ensemble, the component learners should be with high accuracy as well as high diversity. A popularly used scheme in generating accurate but diverse component learners is to perturb the training data with resampling methods, such as the boot-strap sampling used in bagging. However, such a scheme is not very effective on local learners such as nearest-neighbor classifiers because a slight change in training data can hardly result in local learners with big differences. In this paper, a new ensemble algorithm named Filtered Attribute Subspace based Bagging with Injected Randomness (FASBIR) is proposed for building ensembles of local learners, which utilizes multimodal perturbation to help generate accurate but diverse component learners. In detail, FASBIR employs the perturbation on the training data with boot-strap sampling, the perturbation on the input attributes with attribute filtering and attribute subspace selection, and the perturbation on the learning parameters with randomly configured distance metrics. A large empirical study shows that FASBIR is effective in building ensembles of nearest-neighbor classifiers, whose performance is better than that of many other ensemble algorithms. [ABSTRACT FROM AUTHOR]

The flux state quantum bit (qubit) is promising for a solid state implementation of scalable quantum computing. The simplest flux state qubit consists of an rf SQUID with two fluxoid states, which can be readout with a dc SQUID—the most sensitive magnetic flux detector. Efficient readout with less back-action is desirable for quantum computing. In this work, we report measurements of the switching flux and switching current distributions of under damped dc SQUIDs. The data show that single shot readout of flux qubit with very high efficiency (>99%) can be realized using underdamped hysteretic dc SQUIDs. [ABSTRACT FROM AUTHOR]

Stacked gate dielectrics are modeled with respect to the impact on the leakage current of interfacial layers and transition regions, considering the tradeoff with the gate capacitance. A Franz 2-band dispersion model is used. Low-EOT and low-gatecurrent regimes are explored theoretically using reasonable estimates guided by experimental data. Transition layer values of each parameter are qualitatively explored for oxynitride, Si[sub 3]N[sub 4]/SiO[sub 2], and high-K stacks. Higher dielectric constant and more insulating materials are obviously desired for each layer of dielectric; however, the transition region becomes more important as such dielectrics are considered. Higher dielectric constant of interfacial layer is desirable for the low-EOT-low-gate-current requirement. [ABSTRACT FROM AUTHOR]

Reports on the development of a tunneling model to understand the gate current as a function of voltage and temperature, based on the energy-dispersion relation in each region of the gate-dielectric-silicon system. Calculation of the gate capacitance from Schrodinger and Poisson equations subject to Fermi-Dirac statistics.

Investigates the modeling of direct tunneling current through gate dielectric stacks. Gate lengths of complementary metal oxide semiconductors; Assumptions and approximations made in the investigation; Discussion of tunneling currents.

Deals with a study which proposed and evaluated the strength and signal-to-interference ratio (SIR)-combined adaptive power control method for mobile radio channels. Variable step size of the proposed method; Adaptive thresholds of the strength and SIR-combined adaptive power control; Conclusion.

Rabi oscillation between macroscopic quantum states of superconducting devices has important implications to the foundations of quantum mechanics as well as the development of quantum computing. At low temperature and low damping, a Josephson tunnel junction biased slightly below its critical current constitutes a macroscopic two-level quantum system. Here we report the results of a single-qubit rotation experiment in a NbN/AIN/NbN Josephson tunnel junction. We show that the state of the junction qubit can be controlled by varying the duration of the microwave pulses. [ABSTRACT FROM AUTHOR]

Deep models with multiple layers have demonstrated their potential in learning abstract and invariant features for better representation and classification of remote sensing images. Moreover, metric learning (ML) is usually introduced into the deep models to further increase the discrimination of deep representations. However, the usual deep ML methods treat the training samples in each training batch in the stochastic gradient descent-based learning procedure independently, and thus, they neglect the important contextual (structural) information in the training samples. In this paper, we first introduce deep structural ML (DSML) into the literature of remote sensing scene classification and specifically capture and use the structural information during the training on the remote sensing images. Further analysis demonstrates that DSML usually makes many learned metric parameters similar. This similarity leads to obvious model redundancy and thus decreases the representational ability of the model. To address this problem, this paper proposes a new diversity-promoting DSML (D-DSML) method by regularizing the learning procedure by a diversity-promoting prior over the parameter factors. The proposed D-DSML encourages the parameter factors to be uncorrelated, such that each factor can model unique information, and thus, the model's description ability and classification performance would be significantly improved. Experiments over six real-world remote sensing scene data sets demonstrate that the proposed method obtains much better results than those obtained by the original deep models and has comparable or even better performances when compared with state-of-the-art methods. [ABSTRACT FROM AUTHOR]

We proposed a new reservoir computation (RC) structure using polarization dynamics of vertical cavity surface emitting lasers (VCSELs) with optoelectronic feedback. Santa-Fe time-series prediction and nonlinear channel equalization were used to evaluate its parallel processing capability. We numerically discussed the effects of feedback strength, injection strength, frequency detuning, injection current and scaling factors on the RC performance of the system. The results show that, the operation range of negative feedback is larger than that of positive feedback; under appropriate feedback and lager injection strengths, good RC performance can be achieved for a wider injection current; with continuous variation of feedback strength from negative to positive values, the optimized location for frequency detuning moves from positive to negative values. We also evaluated the processing rate of proposed RC structure. The related study is helpful for the design and optimization of VCSEL-based RC under optoelectronic feedback. [ABSTRACT FROM AUTHOR]

The transverse magnetic field (TMF) contacts generate a magnetic field through the structure and apply electromagnetic force to the arc to drive the arc to move on the surface of the contact. When the arc rotates on the surface of the spiral-type TMF contact, it needs to continuously cross the slots in the surface, so that the current is transferred between the contact arms. The structure of the slot not only determines the magnitude of the electromagnetic force of the arc during its movement, but also directly affects the arc’s appearance and speed during its motion. At present, most researches on spiral-type TMF contacts focus on increasing the strength of TMF and enhancing the force on the arc, but there is little research on the influence of the arc’s appearance during the slot crossing process. In this article, two spiral-type TMF contact structures are selected for experiments, the appearance of the arc in the slot crossing process is studied and analyzed, and the arc characteristics in different slot crossing processes are summarized. It is found that the anode plasma jets can keep moving with low concentration, which plays an important role in the slot crossing process and the current breaking. [ABSTRACT FROM AUTHOR]

The multi-path effect makes high speed broadband communications a very challenging task due to the severe inter-symbol interference (ISI). By concentrating energy in both the spatial and temporal domains, time-reversal (TR) transmission technique provides a great potential of low-complexity energy-efficient communications. In this paper, a novel concept of time-reversal division multiple access (TRDMA) is proposed as a wireless channel access method based on its high-resolution spatial focusing effect. It is proposed to use TR structure in multi-user downlink systems over multi-path channels, where signals of different users are separated solely by TRDMA. Both the single-transmit-antenna scheme and its enhanced version with multiple transmit antennas are developed and evaluated in this paper. The system performance is investigated in terms of its effective signal-to-interference-plus-noise ratio (SINR), the achievable sum rate and the achievable rates with outage. And some further discussions regarding its advantage over conventional rake receivers and the impact of spatial correlations between users are given at the end of this paper. It is shown in both analytical and simulation results that desirable properties and satisfying performances can be achieved in the proposed TRDMA multi-user downlink system, which makes TRDMA a promising candidate for future energy-efficient low-complexity broadband wireless communications. [ABSTRACT FROM AUTHOR]

The azimuthal distribution of the ohmic loss in the coaxial waveguide with a misaligned inner rod is investigated in this paper. For axially symmetric modes with zero caustic radii, a little misalignment will bring a large change of the azimuthal ohmic loss distribution on the inner rod and the outer wall, and the change is more noticeable for a larger misalignment or a larger ratio of the inner to the outer radii in a coaxial waveguide; for asymmetric volume modes and whispering-gallery modes with nonzero caustic radii, when the inner rod radius is smaller than the caustic radius of a given mode, the azimuthal ohmic loss distribution is almost unchanged with a small misalignment, but when the inner rod radius is larger than the caustic radius, the azimuthal ohmic loss distribution changes obviously with the misalignment, and this change is larger for the coaxial waveguide with a larger ratio of the inner to the outer radii or a larger misalignment of the inner rod. This noticeable change may cause the azimuthal accumulation of heat on the inner rod and the outer wall in a coaxial waveguide or cavity. [ABSTRACT FROM AUTHOR]

This article presents a novel triband dual-polarized shared-aperture antenna with frequency-selective function for sub-6 GHz base station applications. The proposed antenna is composed of a dual-polarized square loop antenna with two parasitic loops for 2G/3G/4G (1710–2690 MHz) and a differentially fed dual-polarized planar antenna for 5G (3300–3600 and 4800–5000 MHz) base station applications. These two antennas are placed coaxially but different altitudes for saving the installation space. In order to achieve good individual performance for these two antennas in the same aperture without interference or blocking, the lower band (LB) antenna is designed as a frequency-selective surface (FSS) for the nether mid/upper bands (M/UBs) antenna. The measured results show that the proposed antenna achieves a high port isolation (>20 dB) between LB and M/UBs and a −10-dB impedance bandwidth of 50.4% (1.60–2.70 GHz), 14.9% (3.28–3.80 GHz), and 8.6% (4.75–5.18 GHz). To further validate the design concept, an antenna array composed of four LB elements and eight M/UBs elements with the corresponding spacing is fabricated and measured, which demonstrates the application of the triband shared-aperture antenna in array form. [ABSTRACT FROM AUTHOR]

Clock power is the major contributor to dynamic power for modern integrated circuit design. A conventional single-bit flip-flop cell uses an inverter chain with a high drive strength to drive the clock signal. Clustering several such cells and forming a multibit flip-flop can share the drive strength, dynamic power, and area of the inverter chain, and can even save the clock network power and facilitate the skew control. Hence, in this paper, we focus on postplacement multibit flip-flop clustering to gain these benefits. Utilizing the properties of Manhattan distance and coordinate transformation, we model the problem instance by two interval graphs and use a pair of linear-sized sequences as our representation. Without enumerating all possible combinations, we identify only partial sequences that are necessary to cluster flip-flops, thus leading to an efficient clustering scheme. Moreover, our fast coordinate transformation also makes the execution of our algorithm very efficient. The experiments are conducted on industrial circuits. Our results show that concise representation delivers superior efficiency and effectiveness. Even under timing and placement density constraints, clock power saving via multibit flip-flop clustering can still be substantial at postplacement. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge excitated by pulsed power is a promising approach for producing nonthermal plasma at atmospheric pressure, but pulsed power generators vary widely in performance and should be chosen according to application requirements. In this paper, a repetitive unipolar nanosecond-pulse generator is constructed using resonant charging and one-stage magnetic compression circuits, where IGBT and magnetic switches are the key units, respectively. The generator is capable of providing repetitive pulses with a voltage of up to 30 kV and duration of 70 ns at a 300 Ω resistive load. Output pulse voltage can be adjusted by varying ac input voltage or trigger pulse-width. This compact and convenient generator has been used successfully to produce stable dielectric barrier discharge. [ABSTRACT FROM AUTHOR]

Building on a previously presented compact gate capacitance (Cg-Vg) model, a computationally efficient and accurate physically based compact model of gate substrate- injected tunneling current (19-V9) is provided for both ultra- thin SiO2 and high-dielectric constant (high-κ) gate stacks of equivalent oxide thickness (EOT) down to ~ 1 nm. Direct and Fowler-Nordheim tunneling from multiple discrete subbands in the strong inversion layer are addressed. Subband energies in the presence of wave function penetration into the gate dielectric, charge distributions among the subbands subject to Fermi-Dirac statistics, and the barrier potential are provided from the compact Cg-Vg model. A modified version of the conventional Wentzel-Kramer-Brillouin approximation allows for the effects of the abrupt material interfaces and nonparabolicities in complex band structures of the individual dielectrics on the tunneling current. This compact model produces simulation results comparable to those obtained via computationally intense self- consistent Poisson-Schrodinger simulators with the same MOS devices structures and material parameters for 1-nm EOTs of SiO2 and high-κ/SiO2 gate stacks on (100) Si, respectively. Comparisons to experimental data for MOS devices with metal and polysilicon gates, ultrathin dielectrics of SiO2, Si3N4, and high-κ (e.g., HfO2) gate stacks on (100) Si with EOTs down to ~ 1-nm show excellent agreement. [ABSTRACT FROM AUTHOR]

An optimized control approach for the distributed cooperative vehicular platoon was proposed in this paper, considering actuator delay and nonideal communication condition. A hierarchical structure is used to model the vehicular platoon, where the desired acceleration is optimized by CACC controller and the longitudinal tracking controller is proposed to follow it. In the design process of CACC controller, a parameter space approach and linear quadratic regulator (LQR) method are applied to guarantee the string stability and optimized performance. The influence of communication time delay and dropout rate is revealed by the changing of string stable region. Analytical results are verified by numerical simulations of a six-vehicle platoon where the leading vehicle follows the FTP-75 drive cycle speed profile. Furthermore, a Hardware-in-the-Loop (HIL) test is carried out with Carsim to simulate a high-fidelity vehicle dynamic model and dedicated short range communication (DSRC) modems as hardware in the loop as well as the control unit to achieve the inter-vehicle communication. The results show that the designed CACC platooning controller exhibits favorable performance in highway driving scenarios. The platooning vehicles display excellent car-following behavior with high accuracy, driving comfort and safety. [ABSTRACT FROM AUTHOR]

This communication presents a beam-deflection short backfire antenna (BD-SBA). The proposed BD-SBA differs from the conventional SBA in that the main reflector of the BD-SBA is a phase-modulated metasurface instead of a perfect electric conductor (PEC). The phase-modulated metasurface consists of 15 columns of unit cells which are designed to change the phase of the reflected waves. Therefore, the beam of the BD-SBA can be deflected to a certain angle. First, several BD-SBAs with linear phase-modulated metasurfaces are studied, which indicates that the beam of antennas point at different directions. Second, the BD-SBAs with nonlinear phase-modulated metasurfaces are studied to compare the difference between metasurfaces with linear and nonlinear width variation of patch. The simulated results show that the metasurface with nonlinear variation can obtain better performance than the former. To verify this design method, the BD-SBA with $\Delta \theta = 10^{\circ }$ was fabricated and measured at ${X}$ -band. The overall height of the proposed antenna is 0.35 wavelength at 10 GHz. The measured and simulated results are in good agreement; the measured beam-deflection angle, realized gain, and aperture efficiency are 10°, 14.8 dBi, and 68.3% at the center frequency, respectively. Due to the beam-deflection function, medium-to-high gain characteristics, and low profile, the proposed BD-SBA can be expected to find potential applications in wireless backhauling. [ABSTRACT FROM AUTHOR]

In this communication, we present a new method of encoding /decoding information contained in a wave packet using multipath effect. A signal is mixed with an auxiliary signal and sent into an enclosed cavity. The strongly distorted signal transmitted through the cavity is then sent to a receiver, where it is time reversed and sent to a second enclosed metallic cavity that is strictly identical to the first one. As a result, the waveform of the initial signal is reconstructed at a point of the second cavity that is equivalent to the point of the first cavity due to the spatial and temporal focusing. Using the mechanism, secure wireless data transmission is carried out. Finally, the impact of the size of the cavity on intersymbol interference and the frequency dispersion caused by frequency selective fading are discussed. Such a communication system ensures a high level of security. [ABSTRACT FROM AUTHOR]

A 1270 Hz resonance occurred between ±350 kV/ 1000 MW Luxi back-to-back voltage source converter based high-voltage dc transmission (VSC-HVDC) converter and the 525 kV ac grid after disconnection of several ac transmission lines. To understand the resonance and find a solution, the impedance-based stability analysis model considering different equipment is first established. Then, the resonance is analyzed and repeated in the simulation based on the established model. The system stability can be judged by the ratio of grid impedance to the equivalent impedance of all parallel-connected equipment with the converter. To evaluate the occurrence and risk of resonance, the frequency range where the impedance has a negative-real-part has been searched and studied. In order to narrow the negative-real-part region to avoid potential resonance, solutions such as control strategy improvement and passive or active impedance adapter may be applicable and are discussed. For a complex system containing various equipment, the equipment can be divided into several subsectors to avoid modeling all possible combinations of equipment, which can be exhausting. And analysis has shown sufficient but not necessary condition to stabilize the system is to avoid the negative-real-part region in each sector. [ABSTRACT FROM AUTHOR]

A high-performance three-phase pulse width modulation (PWM) converter with reduced dc-link capacitor under unbalanced ac voltage conditions is proposed in this paper. The unique feature of the converter lies in that sinusoidal symmetrical ac currents and ripple free dc voltage can be achieved simultaneously without using a bulky capacitor, which was thought to be a dilemma in the past. The control scheme is implemented in an α–β frame, so the complex rotate transformations are avoided, and it does not require the extraction of positive and negative sequence currents, which simplifies the control algorithm. A two-quadrant operation active power compensator together with its controller is developed to suppress the voltage ripple in the dc-link. Compared with the passive compensation method, the compensator is equipped with a smaller capacitor to reduce the system size, weight, and cost. Moreover, the compensator could be integrated with the conventional three-phase three-leg PWM converter seamlessly. The effectiveness of the proposed control schemes is verified by the experiment results. [ABSTRACT FROM PUBLISHER]

This paper proposes a modified one cycle control (OCC) for active power filter (APF) to compensate only harmonic components of load currents. The conventional OCC-based APF cannot differentiate between the harmonic and reactive components of load currents, which leads to the increment in device current rating because of compensation of large reactive currents besides harmonics. The reference signals of the OCC control core have been reconstructed and the associated control equations have been developed, following the control philosophy of simplicity. The modified scheme is easy to implement and only three more sensors are required for measuring load currents compared with the conventional OCC. This modified OCC guarantees the excellent performance of harmonic compensation alone and retains the advantages of the conventional OCC, such as no phase locking loop and the constant switching frequency. The feasibility and performance of the proposed OCC has been validated by experimental studies on a 5 kVA APF hardware platform developed in laboratory. [ABSTRACT FROM PUBLISHER]

In the traditional neural sensing microstructure, the limited metal line pitch and the metal layer numbers restrict the neural signal routing ability from electrodes to circuit chips. Miniature packaging and excessive noise interference bottlenecks are some of the challenges faced by the electrodes and circuit chips integration with traditional wire bonding. This paper proposes a 2.5-D heterogeneous integration neural sensing microsystem based on the silicon substrate to overcome these issues. With standard semiconductor and 3-D integration processes, high-channel-density (256 channels at 25 mm2) neural sensing microsystem is achieved. Through silicon via provides the shortest vertical interconnection and dramatically minimizes the packaging. Furthermore, the interposer can carry multiple chips to enhance the function of the biosensor. Electrical characteristics and reliability examinations reveal its high quality and great performance as compared to traditional approaches. This novel highly integrated neural sensing microsystem is expected to contribute to the biomedical field for exploring and solving unknown biological mysteries. [ABSTRACT FROM AUTHOR]