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Nowadays, there is a trend to employ adaptive solutions in mobile communication. The adaptive transmission systems seem to answer the need for highly reliable communication that serves high data rates. For efficient adaptive transmission, the future Channel State Information (CSI) has to be known. The various prediction methods can be applied to estimate the future CSI. However, each method has its bottlenecks. The task is even more challenging while considering the future 5G/6G communication where the employment of sub-6 GHz and millimetre waves (mmWaves) in narrow-band, wide-band and ultra-wide-band transmission is considered. Thus, author describes the differences between sub-6 GHz/mmWave and narrow-band/wide-band/ultrawide- band channel prediction, provide a comprehensive overview of available prediction methods, discuss its performance and analyse the opportunity to use them in sub-6 GHz and mmWave systems. We select Long Short-Term Memory Recurrent Neural Network (RNN) as the most promising technique for future CSI prediction and propose optimising two of its parameters - the number of input features, which was not yet considered as an opportunity to improve the performance of CSI prediction, and the number of hidden layers. [ABSTRACT FROM AUTHOR]

Copyright of Space-Integrated-Ground Information Networks is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Independent component analysis (ICA) has been used for data mining in many branches of science. In beam physics, ICA can be applied to analyze turn-by-turn beam position monitor data of beam motion. The narrow-band filtering of ICA provides us methods to identify and extract information on the linear betatron and synchrotron motion, effects of wake fields, etc. We show that the ICA is also a powerful tool to measure nonlinear magnetic field in accelerators. Numerical simulations are used to demonstrate the ability to obtain sextupole strengths at high precision. The methods can be extended to other higher order multipoles. [ABSTRACT FROM AUTHOR]

Background and Aim: The Japan narrow‐band imaging (NBI) Expert Team (JNET) was organized to unify four previous magnifying NBI classifications (the Sano, Hiroshima, Showa, and Jikei classifications). The JNET working group created criteria (referred to as the NBI scale) for evaluation of vessel pattern (VP) and surface pattern (SP). We conducted a multicenter validation study of the NBI scale to develop the JNET classification of colorectal lesions. Methods: Twenty‐five expert JNET colonoscopists read 100 still NBI images with and without magnification on the web to evaluate the NBI findings and necessity of the each criterion for the final diagnosis. Results: Surface pattern in magnifying NBI images was necessary for diagnosis of polyps in more than 60% of cases, whereas VP was required in around 90%. Univariate/multivariate analysis of candidate findings in the NBI scale identified three for type 2B (variable caliber of vessels, irregular distribution of vessels, and irregular or obscure surface pattern), and three for type 3 (loose vessel area, interruption of thick vessel, and amorphous areas of surface pattern). Evaluation of the diagnostic performance for these three findings in combination showed that the sensitivity for types 2B and 3 was highest (44.9% and 54.7%, respectively), and that the specificity for type 3 was acceptable (97.4%) when any one of the three findings was evident. We found that the macroscopic type (polypoid or non‐polypoid) had a minor influence on the key diagnostic performance for types 2B and 3. Conclusion: Based on the present data, we reached a consensus for developing the JNET classification. [ABSTRACT FROM AUTHOR]

Incidents of pedestrian-induced large lateral vibrations of footbridges reveal the occurrence of an instability-type phenomenon in pedestrian-induced vibration. However, the mechanism involved has yet to be clearly explained. In this work, a novel model for predicting the lateral vibration of footbridges is proposed. Under an algebraic framework of nonlinear stochastic vibration, the narrow-band vibration caused by the pedestrian intra-subject randomness and the phase lag between the footbridge motion and the pedestrian load are considered. The critical condition that triggers the large lateral vibration of the footbridge is identified using the stochastic averaging method and the concept of stability based on the Lyapunov exponent. The validity of the proposed method is confirmed through case studies of three bridges. Through a parametric analysis, the effects of several crucial parameters on the stability/instability of vibration are discussed. Finally, conclusions are drawn regarding insights that can be useful to the future designs of footbridges. [ABSTRACT FROM AUTHOR]

Abstract: Background: This is a comparative analysis of the diagnostic accuracy of narrow band imaging (NBI) and laryngovideostroboscopy (LVS) in the assessment of premalignant and malignant vocal fold lesions. Methods: A prospective analysis was performed on 105 consecutive patients with vocal fold lesions. The NBI and LVS were obtained before the microsurgery. Results: The NBI and LVS showed no significant differences in identifying premalignant and malignant pathologies. However, in analysis restricted to identification of only malignant lesions, the specificity (88.9% vs 20.6%), accuracy (90.5% vs 51.4%), and positive predictive value (PPV; 84.8% vs 45.1%) were significantly higher for NBI (P value < .001; .015; and .045, respectively). A comparison of LVS scored results relative to each NBI type revealed statistically significant differences (P < .001). A moderate positive correlation between NBI and LVS was demonstrated (P = .54). Conclusion: The NBI and LVS are useful, complementary tools in evaluating early potential vocal fold malignancies. The NBI was superior to LVS on several statistical analyses. [ABSTRACT FROM AUTHOR]

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Narrow-band imaging (NBI) is an optical technique enhancing mucosal vasculature. The aim of this study is to assess the effectiveness of rigid NBI endoscopy in the early detection of second primaries or local recurrences after treatment for oral (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC), its advantage over standard white-light (WL) endoscopy, and the influence of previous radiotherapy, the learning curve, and lesion site. Between January 2013 and June 2015, 195 patients treated for OSCC or OPSCC with surgery alone (group A) or radiotherapy with or without surgery and/or chemotherapy (group B) underwent additional follow-up assessments using NBI. Sensitivity, specificity, positive/negative predictive values (PPV and NPV), and accuracy for detecting second primaries or local recurrences were calculated for patients with at least two NBI assessments. The effect of previous radiotherapy was determined by test of proportions and that of the learning curve and lesion site with Fisher's exact test. 138/195 patients were included in the analysis. NBI sensitivity, specificity, PPV, NPV, and accuracy for groups A and B were 89.5 vs 100%, 85.2 vs 81.5%, 65.4 vs 69.7%, 96.3 vs 100%, and 86.3 vs 87%, respectively. The diagnostic gain of NBI was 88.2% in group A and 69.6% in group B. The learning curve was the main source of false positives ( p = 0.025), whereas radiotherapy and lesion site were uninfluential ( p = NS). NBI appears useful for follow-up after treatment for OSCC or OPSCC, its performance being affected only by the learning curve and not by previous treatment or lesion site. [ABSTRACT FROM AUTHOR]

In this study, an expendable current profiler sensor is developed to satisfy the actual requirements of an expendable current profiler for measuring electric fields induced by ocean currents. The electric field induced by ocean currents is an important process variable for investigating the motion characteristics of ocean currents; however, accurate measurement thereof is affected by various factors. Amplitude modulation is used to modulate the measured signals into narrow-band, single-frequency signals, thereby reducing the noise level of the sensor when measuring the electric field induced by ocean currents and for extracting ocean current signals in the nanovolt range under high background noise. In this study, front-end weak signal processing circuits are designed, strong interfering signals induced by the descent of the expendable current profiler probe are partially offset by a compensation circuit for the in-phase electric field component, and useful signals are extracted using a filter circuit. System on a programmable chip technology is used for the digital processing module of the expendable current profiler probe, thereby achieving rapid development, rapid optimization, and software/hardware integration of the digital processing module, as well as enhancing the overall performance of the system. In addition, dynamic data transmission technology using an enameled wire with a diameter of 0.1 mm and a length of 2 km is developed to achieve dynamic data transmission requirements for the expendable current profiler surface float. Finally, the ocean current electric field data and ocean temperature data are acquired through experiments. [ABSTRACT FROM AUTHOR]

The uniaxial strain of quasi-one-dimensional conductor whiskers of orthorhombic TaS at a strain higher than ε ~ 0.8% leads to a sharp increase in the coherence of the properties of a charge density wave (CDW), which manifests itself in its motion in fields higher than threshold field E . During uniaxial elongation, TaS is shown to exhibit the following unusual properties even in weak fields: Peierls transition temperature T depends nonmonotonically on ε, one-dimensional fluctuations weaken near T , and the coherence length of a charge density increases at T < T . Investigations in fields higher than E show that the ultracoherent properties of CDW exist in a wide temperature range and are retained when temperature increases up to T . These properties of CDW make it possible to observe a sharp increase in E near T and an almost jumplike increase in E at T < 90 K. The increase in E at T is explained by a decrease in the coherence volume of CDW because of a fluctuational suppression of the Peierls gap. [ABSTRACT FROM AUTHOR]

Enlightened by ASTFA method, adaptive sparsest narrow-band decomposition (ASNBD) method is proposed in this paper. In ASNBD method, an optimized filter must be established at first. The parameters of the filter are determined by solving a nonlinear optimization problem. A regulated differential operator is used as the objective function so that each component is constrained to be a local narrow-band signal. Afterwards, the signal is filtered by the optimized filter to generate an intrinsic narrow-band component (INBC). ASNBD is proposed aiming at solving the problems existed in ASTFA. Gauss-Newton type method, which is applied to solve the optimization problem in ASTFA, is irreplaceable and very sensitive to initial values. However, more appropriate optimization method such as genetic algorithm (GA) can be utilized to solve the optimization problem in ASNBD. Meanwhile, compared with ASTFA, the decomposition results generated by ASNBD have better physical meaning by constraining the components to be local narrow-band signals. Comparisons are made between ASNBD, ASTFA and EMD by analyzing simulation and experimental signals. The results indicate that ASNBD method is superior to the other two methods in generating more accurate components from noise signal, restraining the boundary effect, possessing better orthogonality and diagnosing rolling element bearing fault. [ABSTRACT FROM AUTHOR]

A new low-cost reconfigurable software-defined radio (SDR) platform for high-frequency (HF) applications is presented in this article. The platform can work in the entire HF band (3-30 MHz), with bandwidths up to 36 kHz. We present the preliminary results working in a near vertical incidence skywave (NVIS) communication, where only the frequency range 3- 12 MHz is needed. The modem has been designed so that the modulations to be used, time frames, and scheduling can be completely reprogrammable in both narrow-band and wide-band modes. This is a strong advantage, because tests can be redesigned and reprogrammed to evaluate channel performance, which is not only important for research purposes but also for its final application in emergency communications in the NVIS propagation case of study. The transmission can be adapted to the best propagation frequency at every moment by means of a previous sounding analysis. [ABSTRACT FROM PUBLISHER]

Ultrawideband (UWB) communication channels cause pulse distortion and result in many multipath components arriving at the receiver in clusters. In this paper, the effects of lossy dielectric walls on UWB pulses are analyzed. The frequency-dependent parameters of commonly used building materials are used to analyze the effects of multiple reflections and transmissions, material distortion, and interpulse interference on the UWB pulse waveform. The possibility of polarization-dependent distortion is discussed. Various thicknesses of walls and angles of incidence are considered. The distortion due to each effect is quantified in terms of maximum correlation coefficients (MCCs). The overall effect of the wall is modeled as a tapped-delay-line filter based on the MCC. The results are used to specify the multicluster structure of UWB channel models for indoor communication. [ABSTRACT FROM PUBLISHER]

An efficient algorithm based on high-order cumulant is addressed for the scenarios where both far-field and near-field narrow-band signals may exist synchronously. The first matrix built by four-order cumulant is utilized to estimate the two dimensional direction-of-arrivals (DOAs) using the orthogonal projection matrix of the signal subspace and the virtual steering matrix. Then, the second matrix built by four-order cumulant is decomposed to get the noise subspace using the eigen decomposition. Meanwhile, a virtual steering matrix is used to distinguish far-field signals (FFSs) from near-field signals (NFSs). And one-dimensional MUSIC algorithm is used to estimate the range of the NFSs. Compared to the TSMUSIC, the proposed algorithm can provide high resolution for the DOAs. In addition, there is higher accuracy for the DOA of NFS in the proposed algorithm than that in TSMUSIC and in TSMD. Simulation results are carried out to certify the performance of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Inspired by track-before-detection technology in radar, a novel time-frequency transform, namely polynomial chirping Fourier transform (PCFT), is exploited to extract components from noisy multicomponent signal. The PCFT combines advantages of Fourier transform and polynomial chirplet transform to accumulate component energy along a polynomial chirping curve in the time-frequency plane. The particle swarm optimization algorithm is employed to search optimal polynomial parameters with which the PCFT will achieve a most concentrated energy ridge in the time-frequency plane for the target component. The component can be well separated in the polynomial chirping Fourier domain with a narrow-band filter and then reconstructed by inverse PCFT. Furthermore, an iterative procedure, involving parameter estimation, PCFT, filtering and recovery, is introduced to extract components from a noisy multicomponent signal successively. The Simulations and experiments show that the proposed method has better performance in component extraction from noisy multicomponent signal as well as provides more time-frequency details about the analyzed signal than conventional methods. [ABSTRACT FROM AUTHOR]

Narrow-band terahertz emission from coherently excited spin precession in metallic ferrimagnetic Mn3-xGa Heusler alloy nanofilms has been observed. The efficiency of the emission, per nanometer film thickness, is comparable or higher than that of classical laser-driven terahertz sources based on optical rectification. The center frequency of the emission from the films can be tuned precisely via the film composition in the range of 0.20–0.35 THz, making this type of metallic film a candidate for efficient on-chip terahertz emitters. Terahertz emission spectroscopy is furthermore shown to be a sensitive probe of magnetic properties of ultra-thin films. [ABSTRACT FROM AUTHOR]

The features of forming output radiation in a powerful monopulse single-frequency side diode-pumped laser operating in external narrow-band signal seeding mode were investigated. The monopulse single-frequency laser was fabricated of a YAG:Nd active element excited by three laser diode matrices. A compact continuous-wave YAG:Nd-laser with longitudinal diode pumping served as the seeding laser. It was shown experimentally that the transition of the monopulse laser from multimode to single-frequency lasing with a spectral line width of about 54 MHz (0.2 pm) occurs at seeding-laser radiation power P ≈ 0.14 mW (radiation intensity of 1.8·10 W/cm). Increasing the seeding-laser power over P does not lead to a noticeable change of the output characteristics of the monopulse laser for a given pump level (above the threshold). If the pump power varies from 1.5 to 3.0 kW, the P value is not changed but the energy of the output pulses of single-frequency monopulse generation increases to 40 MJ. The low level of the external narrow-band seeding signal allows us to consider the single-frequency low-power semiconductor laser as a promising source of the seeding signal. [ABSTRACT FROM AUTHOR]

Background: Magnifying endoscopy (ME) with narrow-band imaging (NBI) can visualize a white opaque substance (WOS) in gastric epithelial neoplasms, gastric intestinal metaplasias, and colorectal epithelial neoplasms. Histological examination showed the WOS to be lipid droplets accumulated in the epithelium. The white appearance of colorectal hyperplastic polyps suggests that they may contain WOS, but this has not been investigated as yet. Aims: The purpose of this study was to determine whether WOS is present in colorectal hyperplastic polyps. Methods: We retrospectively evaluated endoscopic images of 26 consecutive lesions investigated by ME with NBI and subsequently endoscopically resected and confirmed to be hyperplastic polyps. Results: WOS was present in 21 of the 26 colorectal hyperplastic polyps (80.8%) based on the findings of ME with NBI. Adipophilin was present in 24 of the 26 colorectal hyperplastic polyps (92.3%). Conclusions: This study is the first to demonstrate that WOS (i.e. lipid droplets) accumulates in the epithelium of colorectal hyperplastic polyps. [ABSTRACT FROM AUTHOR]

Background: The "resect and discard" strategy is beneficial for cost savings on screening and surveillance colonoscopy, but it has the risk to discard lesions with advanced histology or small invasive cancer (small advanced lesion; SALs). The aim of this study was to prove the principle of new "resect and discard" strategy with consideration for SALs using magnifying narrow-band imaging (M-NBI).Methods: Patients undergoing colonoscopy at a tertiary center were involved in this prospective trial. For each detected polyp <10 mm, optical diagnosis (OD) and virtual management ("leave in situ", "discard" or "send for pathology") were independently made using non-magnifying NBI (N-NBI) and M-NBI, and next surveillance interval were predicted. Histological and optical diagnosis results of all polyps were compared.Results: While the management could be decided in 82% of polyps smaller than 10 mm, 24/31 (77%) SALs including two small invasive cancers were not discarded based on OD using M-NBI. The sensitivity [90% confidence interval (CI)] of M-NBI for SALs was 0.77 (0.61-0.89). The risk for discarding SALs using N-NBI was significantly higher than that using M-NBI (53 vs. 23%, p = 0.02). The diagnostic accuracy (95% CI) of M-NBI in distinguishing neoplastic from non-neoplastic lesions [0.88 (0.86-0.90)] was significantly better than that of N-NBI [0.84 (0.82-0.87)] (p = 0.005).Conclusions: The results of our study indicated that our "resect and discard" strategy using M-NBI could work to reduce the risk for discarding SALs including small invasive cancer (UMIN-CTR, UMIN000003740). [ABSTRACT FROM AUTHOR]

The hearing sensitivity of a 2-yr-old male harbor porpoise was measured using a standard psycho-acoustic technique under low ambient noise conditions. Auditory sensitivity was measured for narrow-band 1 s sweeps (center frequencies: 0.125-150 kHz). The audiogram was U-shaped; range of best hearing (within 10 dB of maximum sensitivity) was from 13 to ~140 kHz. Maximum sensitivity (threshold: ~39 dB re 1 µPa) occurred at 125 kHz at the peak frequency of echolocation pulses produced by harbor porpoises. Reduced sensitivity occurred at 32 and 63 kHz. Sensitivity fell by ~10 dB per octave below 16 kHz and declined sharply above 125 kHz. Apart from this individual's ca. 10 dB higher sensitivity at 0.250 kHz, ca. 10 dB lower sensitivity at 32 kHz, and ca. 59 dB lower sensitivity at 150 kHz, his audiogram is similar to that of two harbor porpoises tested previously with a similar psycho-acoustic technique. [ABSTRACT FROM AUTHOR]

Antenna tuning is a very promising technique to cope with the expansion of the mobile communication frequency spectrum. Tunable antennas can address a wide range of operating frequencies, while being highly integrated. In particular, high-Q antennas (also named narrow-band antennas) are very compact, thus are good candidates to be embedded on fourth generation handsets. This study focuses on 'high-Q' tunable antennas and contributes with a characterisation of their loss mechanism, which is a major parameter in link-budget calculations. This study shows, through an example, that the tuner loss is not sufficient to explain the total loss of tunable antennas. It is found that thermal loss -because of the metal conductivity of the antenna itself - plays a major role in the loss mechanism of narrow-band tunable antennas. The investigated high-Q planar inverted F antenna designs exhibit a significant thermal loss; at 1400 MHz nearly 2 dB are lost solely because of the copper conductivity. Thermal loss poses a limitation to achievable performance of tunable antennas and to antenna miniaturisation. [ABSTRACT FROM AUTHOR]

Integrated sensor interface circuits require energy-efficient high-resolution data converters. This paper proposes a two-step incremental A/D converter (IADC) which extends the performance of an Nth-order IADC close to that of a (2N-1)th-order IADC. The implemented device uses the circuitry of a second-order IADC (IADC2) to achieve close to third-order SNR performance. The proposed circuit does not require very high opamp DC gain; the gain can be as low as 60 dB for 100 dB SNR data conversion. The implemented IADC achieves a measured dynamic range of 99.8 dB, and an SNDR of 91 dB for a maximum input 2.2 VPP and a bandwidth of 250 Hz. Fabricated in 65 nm CMOS, the IADC's core area is 0.2 mm 2 , and it consumes only 10.7 µW. The measured FoMs are 0.76 pJ/conversion and 173.5 dB, both among the best reported results for IADCs. The measured results verify that the proposed two-step IADC is a more energy-efficient data conversion scheme than conventional high-order IADCs. [ABSTRACT FROM PUBLISHER]

Orthogonal frequency-division multiplexing (OFDM) is one of the most widely used technologies in current wireless communication systems and standards. Cognitive radio (CR) provides a robust solution to the problem of spectrum congestion as it offers opportunistic usage of frequency bands that are not occupied by primary users. Due to the underlying sensing, spectrum shaping, scaling, and interoperable capabilities of OFDM, it has been adapted as a best transmission technology for CR wireless systems. However, the performance of an OFDM-based CR wireless system is affected by the existence of narrowband interference (NBI) from other users. Further, due to carrier frequency offset in NBI sources, NBI energy may spread over all subcarriers of an OFDM signal. In this paper, a fixed Amplify-and-Forward (AF) relay that operates at a frequency band that is different from that of direct mode is introduced to suppress the effect of NBI. Analytical expressions are derived for outage probability in direct, AF-relay, and incremental relaying modes. The outage performance of the proposed AF relay-based CR network is proven to be better than that of direct mode. [ABSTRACT FROM AUTHOR]

This paper deals with the follower jamming (FJ) and partial-band jamming (PBJ) resistance for the frequency hopping (FH) communication system with low hopping rate over AWGN channel. To gain a comprehensive FJ and PBJ rejection capability, we propose a multi-pattern frequency hopping (MPFH) scheme. In MPFH, the data channel and complementary channel are hopped on separate frequency slots determined by their respective frequency patterns, which will lure the follower jammer out of aiming at the complementary channel, thus mitigating the effect of FJ. Besides, narrow-band receiver is employed to ensure its PBJ rejection capability. We further enhance the proposed scheme by employing convolutional coding and maximum-likelihood decoding. Its upper bounds on bit error rate (BER) are derived under FJ and PBJ, respectively. Effects of three FJ parameters (tracking success probability, jamming duration ratio and jamming bandwidth ratio) and one PBJ parameter (jamming bandwidth ratio) on BER performance of MPFH are investigated versus the conventional FH/BFSK and recently developed differential frequency hopping (DFH) system. Numerical and simulation results show that when under the worst-case FJ, the proposed MPFH performs as well as DFH, but outperforms the conventional FH/BFSK by more than 5 dB; on the other hand, when under worst-case PBJ, the MPFH has the similar BER performance as conventional FH/BFSK, but outperforms DFH by more than 5 dB. The proposed MPFH shows superior jamming rejection performance under both PBJ and FJ. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a new type of microstrip vias-free balanced-to-balanced diplexer suitable for narrow-band applications is presented. The structure of the balanced diplexer is based on two balanced bandpass filters designed for f1=1.1 GHz and f2=1.8 GHz and two transmission lines used to satisfy the open circuit conditions required in the diplexer's design. This diplexer exhibits good common-mode rejection ratio better than 40 dB at the passbands. The attenuation is better than 35 dB at the rejection bands. The isolation between output ports is better than 50 dB. Simulated and experimental results are compared with good agreement. The diplexer is easy of fabricate and integrate with others planar balanced devices. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:567-570, 2015 [ABSTRACT FROM AUTHOR]

The wavelet packets based multicarrier (MC) multicode (MCD) code-division multiple-access (CDMA) transceiver consists of the MCD part, which ensures the transmission for high speed and flexible data rate; the MC part contributing to robustness to frequency-selective fading and flexibility for handling multiple data rates; and wavelet packets (WPs) modulation technique, which contributes to the mitigation of the interference problems. As WPs have lower sidelobes compared with sinusoidal carriers, this system is very effective in reducing the problem of inter-carrier interference. Of course, like any CDMA system, the system can suppress a given amount of interference. This paper considers an interference suppression scheme which will enhance the performance of the system. The receiver employs suppression filters to mitigate the effect of narrow-band jammer interference. The framework for the system and the performance evaluation are presented in terms of the bit error rate and the outage probability over a Nakagami fading channel. Also, we investigate how the performance is influenced by various parameters, such as the number of taps of the suppression filter and the ratio of narrow-band interference bandwidth to the spread-spectrum bandwidth. Finally, the performance of the system is compared with the performance of sinusoidal based MC/MCD-CDMA system denoted Sin-MC/MCD-CDMA. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Curative treatment of patients with gastric cancer requires reliable detection of early gastric cancer. Magnifying endoscopy with narrow-band imaging (M-NBI) is useful for the accurate preoperative diagnosis of early gastric cancer. However, the role of M-NBI in screening endoscopy has not been established. The aims of this study were to determine the feasibility and limitations of M-NBI in screening endoscopy. Methods: We conducted a multicenter prospective uncontrolled trial of patients undergoing routine screening endoscopy patients. We determined the diagnostic accuracy, sensitivity and specificity of M-NBI according to the degree of certainty and need for biopsy, as assessed using the VS (vessel plus surface) classification system. We analyzed the endoscopic and histopathological characteristics of both false negative and false positive high confidence M-NBI diagnoses. We then developed a provisional diagnostic strategy based on the diagnostic performance and limitations identified in this study. Results: A total of 1097 patients were enrolled in the study. We analyzed 371 detected lesions (20 cancers and 351 non-cancers). The accuracy, sensitivity and specificity of high confidence M-NBI diagnoses were 98.1, 85.7 and 99.4 %, respectively. The false negative case was a pale mucosal lesion with tissue diagnosis of signet-ring cell carcinoma. Exclusion of pale mucosal lesions increased the accuracy, sensitivity and specificity of high confidence M-NBI diagnoses to 99.4, 100 and 99.4 %, respectively. We therefore propose a practical strategy targeting non-pale mucosal lesions. Conclusions: With a refined strategy considering its limitations, M-NBI can act as an 'optical biopsy' in screening endoscopies. [ABSTRACT FROM AUTHOR]

A finite-difference based numerical method for the simulation of multiphase incompressible flows is presented. The proposed algorithm adapts the gradient-augmented level set method of Nave et al. [25] for use in multiphase fluid simulations by interpolating the fluid velocity and introducing a simple reinitialization procedure. The method is carried out only along a narrow band surrounding the interface, reducing computational effort while preserving the advantages of the gradient-augmented method. Numerical results show excellent agreement with an analytical solution and available experimental data. A new experimental benchmark is introduced, using data gathered in a wedge-driven wave tank. In addition to the optimally local advection scheme and sub-grid resolution afforded by the new method, numerical comparisons with the standard level set method reveal superior volume conservation. [ABSTRACT FROM AUTHOR]

The mitigation of narrow-band interference (NBI) is an appealing topic in the synthetic aperture radar (SAR) community. It is an underdetermined single-channel separation problem. This paper proposes a method for NBI mitigation using the independent subspace analysis. First, each single pulse is transformed onto a manifold time-frequency distribution by the short-time Fourier transform (STFT). Then, the singular value analysis is carried out to extract the prominent features corresponding to the NBIs. Next, independent component analysis is employed to obtain statistically independent basis components. Furthermore, the independent subspaces corresponding to NBI are reconstructed and subtracted from the raw signal space. The signal with NBI mitigated is resynthesized by inverse STFT. Finally, after processing all the pulses, a well-focused SAR imagery is obtained by a conventional imaging algorithm. Experimental results of simulated and measured data have demonstrated the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

The nonclassical photon pair, generated via a parametric process, is naturally endowed with a specific form of frequency-time quantum correlations. Here, we report complete control of frequency-time quantum correlations of narrow-band biphotons generated via spontaneous four-wave mixing in a cold atomic ensemble. We have experimentally confirmed the generation of frequency-anticorrelated, frequency-correlated, and frequency-uncorrelated narrow-band biphoton states, as well as verifying the strong nonclassicality of the correlations. Our work opens up new possibilities for engineering narrow-band entangled photons for various quantum optical and quantum information applications. [ABSTRACT FROM AUTHOR]

A distinctive connection method in cascaded RF/MW active device system achieving both stability and low gain loss is presented. Unlike traditional methods (isolator and attenuator), the proposed solution introduces an appropriate length of transmission line to change the input impedance at the out-band instable frequency point and uses a narrow-band termination to absorb the instable power without deteriorating in-band signal. Moreover, the reason that instability often occurs in the cascaded system is analysed with S-parameters, and it turns out to be a kind of out-band instability. The solution is verified by an adjustable circuit example whose insertion loss is below 0.3 dB. [ABSTRACT FROM AUTHOR]

ABSTRACT A meandered substrate integrated waveguide (SIW) has been proposed for the frequency scanning array that has potential application of the low cost 24-GHz Doppler radar system. All radiating slots are connected in series using a short circuit ended SIW; therefore, its radiation beam can be steered with frequency. The modified antenna with meandering structure is proposed to enhance the scanning range. The physical slot spacing is kept at about half free space waveguide, whereas the electrical spacing is about 540° at the center frequency of 24 GHz. A broadside radiation is achieved at 24-GHz frequency and a ±30° continuous scanning range is experimentally confirmed with the frequency band from 23 to 25 GHz. Another antenna with center frequency of 77 GHz is designed and tested. It also achieves a ±30° continuous scanning range with the frequency band from 75 to 79 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1478-1483, 2014 [ABSTRACT FROM AUTHOR]

ABSTRACT A novel single-feed circularly polarized microstrip antenna with compact size is proposed for indoor wireless local area network (WLAN) applications. The antenna structure consists of eight slits which are introduced at the boundary and the corners in the radiating square patch with a cross-slot at the center. The proposed antenna shows a compactness of 42% compared with the conventional circularly polarized antenna design at indoor WLAN frequency band. It is found that the resonance frequency of the proposed structure is highly depending on length and width of cross-slot and corner slit for entire band of circular polarization. The 3 dB axial ratio bandwidth of the proposed antenna is 1.9%. Proposed structure is fabricated on the FR-4 epoxy substrate and fed by a single coaxial probe. Measured results show a good agreement with the simulated results. Antenna shows stable radiation characteristics for the entire operating band. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1313-1317, 2014 [ABSTRACT FROM AUTHOR]

In this paper, we propose a low-complexity blind carrier frequency offset (CFO) estimation scheme for constant modulus (CM)-signaling-based orthogonal frequency-division multiplexing (OFDM) systems. Provided that the channel can be assumed to be slowly time-varying, subcarriers having the same indexes in two consecutive OFDM symbols will experience nearly the same channel effect. This assumption enables us to derive a cost function that is determined by the sum of the products of the signal amplitudes on each pair of equivalent subcarriers from two successive OFDM symbols. The maximization process of this cost function makes it possible to find an appropriate estimate of the CFO. Over frequency-selective Rayleigh fading channels, the proposed CFO estimation method provides improved performance over existing techniques. Moreover, in the context of narrow-band noise and signal gain variations, the simulations demonstrate the robustness and immunity of our scheme. [ABSTRACT FROM PUBLISHER]

Peak filtering methods are commonly used in track-following control of hard disk drives (HDDs) to suppress narrow-band disturbances around a specific frequency. When there are significant plant dynamics within the bandwidth of the filter, the closed-loop system is prone to be unstable due to the lightly damped poles of the filter, as well as lightly damped poles of the plant. On the other hand, settling response of such peak filters during shock disturbances is slow, and increases tremendously with decreasing damping ratios. In this article, we present a novel design of peak filters with improved transient responses using a phase scheduling method in addition to varying gain and damping ratio. By doing so, the stability margin of the closed-loop systems during both transient stage and steady-state stage will be improved. The effectiveness of the proposed methodology is verified with extensive simulations and the proposed method is then applied in an integrative servo analysis platform to carry out a scaling exercise to evaluate and predict servo performance to support 10 Terabits/in2. [ABSTRACT FROM AUTHOR]

Some new focusing properties of time-domain ultra wide band (UWB) focusing array antennas are presented. The large current radiator (LCR) is considered as the UWB antenna element. Each LCR is replaced by a set of infinitesimal dipoles modeling both the near field and the far field patterns of the antenna element, as well as the coupling between the elements. Several antenna arrays with different sizes and numbers of elements are modeled. It is shown that similar to narrow band antennas, the actual maximum field region shifts from the intended focus region towards the antenna aperture. [ABSTRACT FROM AUTHOR]

A planar generator based on a free-electron maser (FEM generator) is developed employing a relativistic sheet electron beam (0.8 MeV/1 kA/4 μs) formed by an ELMI accelerator. A hybrid two-mirror resonator consisting of a two-dimensional upstream and a one-dimensional downstream Bragg reflectors is used as the electrodynamic system. The use of two-dimensional distributed feedback implemented in the upstream Bragg structure has made it possible to achieve stable well reproducible single mode generation regime with transverse dimensions of the system of ∼25 × 2.5 wavelengths. Experiments carried out at a frequency of 75 GHz have yielded narrow-band radiation with spectrum width of ∼20 MHz in pulses with a duration of ∼100-200 ns and power of 30-50 MW. [ABSTRACT FROM AUTHOR]

This paper presents a low-cost hyperspectral measurement setup in a new application based on fluorescence detection in the visible (Vis) wavelength range. The aim of the setup is to take hyperspectral fluorescence images of viscous materials. Based on these images, fluorescent and non-fluorescent impurities in the viscous materials can be detected. For the illumination of the measurement object, a narrow-band high-power light-emitting diode (LED) with a center wavelength of 370 nm was used. The low-cost acquisition unit for the imaging consists of a linear variable filter (LVF) and a complementary metal oxide semiconductor (CMOS) 2D sensor array. The translucent wavelength range of the LVF is from 400 nm to 700 nm. For the confirmation of the concept, static measurements of fluorescent viscous materials with a non-fluorescent impurity have been performed and analyzed. With the presented setup, measurement surfaces in the micrometer range can be provided. The measureable minimum particle size of the impurities is in the nanometer range. The recording rate for the measurements depends on the exposure time of the used CMOS 2D sensor array and has been found to be in the microsecond range. [ABSTRACT FROM AUTHOR]

In the article the flight data measurement and transmission to the ground control station for further decoding and post-processing are described. The article demonstrates the developed flight data processing and visualization tool with its operation algorithm. Some possible options of the tool such as trajectory displaying in the three-dimensional coordinates, using Google Earth satellite mapping and arbitrary combining graphs of unmanned aerial vehicles real flight parameters with their explanation were represented. [ABSTRACT FROM AUTHOR]

Fundamental bandwidth limitations on the design of ultra high frequency (UHF) radio frequency identification (RFID) tags are investigated. This study was conducted by considering the optimum equivalent-circuit network necessary for bandwidth broadening in single resonant UHF-RFID tags with conjugate matching. This equivalent-circuit network is simply a parallel combination of an inductor and a resistor cascaded to the UHF-RFID chip. Bandwidth optimisation of the resulting network is validated by means of the Bode criterion. According to this analysis, a broadband UHF-RFID tag prototype able to operate worldwide is designed and fabricated. In order to reduce tag size and cost, the external matching network is omitted in the reported implementation. The measured read ranges are above 5 m within the whole UHF-RFID frequency band (840- 960 MHz), with a peak value of 9 m at 870 MHz. [ABSTRACT FROM AUTHOR]

The estimation of the directions of arrival (DoAs) of narrow-band signals impinging on a linear antenna array is addressed within the Bayesian compressive sensing (BCS) framework. Unlike several state-of-the-art approaches, the voltages at the output of the receiving sensors are directly used to determine the DoAs of the signals thus avoiding the computation of the correlation matrix. Towards this end, the estimation problem is properly formulated to enforce the sparsity of the solution in the linear relationships between output voltages (i.e., the problem data) and the unknown DoAs. Customized implementations exploiting the measurements collected at a unique time instant (single-snapshot) and multiple time instants (multiple-snapshots) are presented and discussed. The effectiveness of the proposed approaches is assessed through an extensive numerical analysis addressing different scenarios, signal configurations, and noise conditions. Comparisons with state-of-the-art methods are reported, as well. [ABSTRACT FROM PUBLISHER]

This paper presents an adaptive control scheme for identifying and rejecting unknown and/or time-varying narrow-band vibrations. We discuss an idea of safely and adaptively inverting a (possibly non-minimum phase) plant dynamics at selected frequency regions, so that structured disturbances (especially vibrations) can be estimated and canceled from the control perspective. By taking advantage of the disturbance model in the design of special infinite-impulse-response (IIR) filters, we can reduce the adaptation to identify the minimum amount of parameters, achieve accurate parameter estimation under noisy environments, and flexibly reject the narrow-band disturbances with clear tuning intuitions. Evaluation of the algorithm is performed via simulation and experiments on an active-suspension benchmark. [ABSTRACT FROM AUTHOR]

The paper presents a direct adaptive algorithm for the rejection of unknown time-varying narrow band disturbances, applied to an adaptive regulation benchmark. The objective is to minimize the residual force by applying an appropriate control signal on the inertial actuator in the presence of multiple and/or unknown time-varying disturbances. The direct adaptive control algorithm is based on the internal model principle (IMP) and uses the Youla–Kučera (YK) parametrization. A direct feedback adaptive regulation is proposed and evaluated both in simulation and real-time. The robustness is improved by shaping the sensitivity functions of the system through band stop filters (BSF). [ABSTRACT FROM AUTHOR]

Adaptive regulation is an important issue with a lot of potential for applications in active suspension, active vibration control, disc drives control and active noise control. One of the basic problems from the “control system” point of view is the rejection of multiple unknown and time varying narrow band disturbances without using an additional transducer for getting information upon the disturbances. An adaptive feedback approach has to be considered for this problem. Industry needs to know the state of the art in the field based on a solid experimental verification on a representative system using currently available technology. The paper presents a benchmark problem for suppression of multiple unknown and/or time-varying vibrations and an associated active vibration control system using an inertial actuator with which the experimental verifications have been done. The objective is to minimize the residual force by applying an appropriate control effort through the inertial actuator. The system does not use any additional transducer for getting real-time information about the disturbances. The benchmark has three levels of difficulty and the associated control performance specifications are presented. A simulator of the system has been used by the various contributors to the benchmark to test their methodology. The procedure for real-time experiments is briefly described. 1 1 The GIPSA-LAB team has done the experiments for all the contributors. The performance measurement methods used will be presented as well as an extensive comparison of the results obtained by various approaches. 2 2 Simulation and Real-time results are presented by each contributor in their papers [3,11,17,30,10,1,7] . [ABSTRACT FROM AUTHOR]

The paper presents an indirect adaptive regulation algorithm for the attenuation of unknown narrow-band disturbances. The main features of this new scheme are (i) the use of adaptive Band-stop Filters (BSFs) tuned at the frequencies of the disturbance and (ii) a procedure for direct identification of frequencies contained in the disturbance. The use of adaptive BSFs allows one to introduce the desired attenuation of the disturbance (instead of total rejection) and simplifies the shaping of the output sensitivity function (to meet the specification for the tolerated amplification outside the frequencies of the disturbance). The proposed approach is evaluated on the benchmark simulator and on the benchmark active vibration control system. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a second iteration Sierpinski carpet fractal shape UWB antenna with hexagonal boundary is presented. The antenna covers the frequency band from 3GHz to 12GHz (VSWR≤2). The proposed antenna has the capability to reject 5.15–5.825GHz band assigned for IEEE802.11a and HIPERLAN/2 which is achieved by embedding a ‘Y’ shaped slot in the radiator that extends to the central conductor of the CPW feed as well. A fabricated prototype is developed where the simulation and experimental results are in good agreement. Measured peak antenna gain varies from 1.25dBi to 6dBi within the band. The proposed antenna has a compact size of 33mm×32mm that includes the substrate around the radiating element. Time domain characteristic reveal that the antenna is non-dispersive with a variation of measured group delay within 0.5ns over the entire band. [Copyright &y& Elsevier]

This article presents a novel interdigital capacitor resonator (ICR), which has a high spurious frequency and compact size. A six-pole high-temperature superconducting (HTS) bandpass filter (BPF) has been designed and fabricated with this ICR on a double-sided MgO-based YBCO thin film. Measurement at cryogenic temperature shows a fractional bandwidth of 0.4%, and an ultra high spurious passband at about 4.1 f0. Moreover, the measurement shows a good agreement with simulation in wideband response. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:443-447, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27324 [ABSTRACT FROM AUTHOR]