Record 1 of 319

Title: 10 Gbps DPSK transmission over free-space link in the mid-infrared

Author(s): Su, YL (Su, Yulong); Wang, W (Wang, Wei); Hu, XH (Hu, Xiaohong); Hu, H (Hu, Hui); Huang, XN (Huang, Xinning); Wang, YS (Wang, Yishan); Si, JH (Si, Jinhai); Xie, XP (Xie, Xiaoping); Han, B (Han, Biao); Feng, H (Feng, Huan); Hao, Q (Hao, Qiang); Zhu, GS (Zhu, Guoshen); Duan, T (Duan, Tao); Zhao, W (Zhao, Wei)

Source: OPTICS EXPRESS  Volume: 26  Issue: 26  Pages: 34515-34528  DOI: 10.1364/OE.26.034515  Published: DEC 24 2018  

Abstract: We experimentally demonstrate the implementation of 10 Gbps high-speed mid-infrared (MIR) free-space optical (FSO) communication, by means of our developed robust high-speed MIR transmitter and receiver modules. Such modules can enable frequency down- and up-conversion between 1550 nm and 3594 nm based on difference frequency generation (DFG) in MgO-doped periodically poled LiNbO3 (MgO: PPLN). The MIR transmitter generates 5.34 dBm power at 3594 nm for input powers of 33 dBm at 1550 mn and 37 dBm at 1083 nm. The MIR receiver regenerates -24.5 dBm power at 1550 nm for input powers of -1.2 dBm at 3594 nm and 36.7 dBm at 1083 nm. The eye diagram of regenerated 1550 nm signal is clear, and both for the on-off keying (OOK) and differential phase shift keying (DPSK) modulation, the power penalties compared with back to back (BTB) signals are lower than 3.5 dB measured at bit error ratio (BER) of 1E-6. According to our analyses, the system supports variable data rate, wavelength, and modulation format. Furthermore, the optical and electrical components are well integrated and fixed in MIR transmitter and receiver modules, which exhibit long-term stability and can be applied to field experiments. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Accession Number: WOS:000454149000088

PubMed ID: 30650874

Author Identifiers:

ISSN: 1094-4087

Record 2 of 319

Title: Photoelectron backscattering in the microchannel plate photomultiplier tube

Author(s): Chen, P (Chen, Ping); Tian, JS (Tian, Jinshou); Guo, LH (Guo, Lehui); Wei, YL (Wei, Yonglin); Liu, HL (Liu, Hulin); Sai, XF (Sai, Xiaofeng); Wang, X (Wang, Xing); Lu, Y (Lu, Yu); Wang, C (Wang, Chao); Wang, JF (Wang, Junfeng); He, K (He, Kai); Tian, LP (Tian, Liping); Xin, LW (Xin, Liwei); Guo, HT (Guo, Haitao)

Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT  Volume: 912  Special Issue: SI  Pages: 112-114  DOI: 10.1016/j.nima.2017.10.081  Published: DEC 21 2018  

Abstract: The late pulse occurring in photomultiplier tubes (PMTS) is attributed to photoelectron backscattering. The small effective open area of microchannel plates (MCPs) increases the probability of photoelectrons bouncing on the front surface of MCPs and aggravates late pulses. In this work, a three-dimensional MCP-PMT model is developed in CST particle studio, a powerful electromagnetic field simulation program, to evaluate the effects of secondary emission yield (SEY) property of the MCP input facet and electric field on the photoelectron backscattering. Timing properties and the number of collected electrons are extracted without smearing due to electronic noise and finite pulse width. Results predict that the collection efficiency (CE) and the time performance can be improved by coating the MCP Nickel-Chromium input electrode with a high SEY material and operating in a proper photocathode-MCP bias voltage. (C) 2017 Elsevier B.V. All rights reserved.

Accession Number: WOS:000453717200030

Conference Title: 8th International Conference on New Developments in Photodetection (NDIP)

Conference Date: JUL, 2017

Conference Location: Tours, FRANCE

Conference Sponsors: CEA, DRF, Inst Res Fundamental Laws Universe, CEA Tech LIST, CNRS, Inst Natl Physique Nucl Physique Particules, Univ Paris Diderot, Lab AstroParticule Cosmologie, CNRS, Ecole Polytechnique, Lab Physique Interfaces Couches Minces

Author Identifiers:

ISSN: 0168-9002

eISSN: 1872-9576

Record 3 of 319

Title: Coherent synthesis of ultrashort pulses based on balanced optical cross-correlator

Author(s): Huang, P (Huang Pei); Fang, SB (Fang Shao-Bo); Huang, HD (Huang Hang-Dong); Hou, X (Hou Xun); Wei, ZY (Wei Zhi-Yi)

Source: ACTA PHYSICA SINICA  Volume: 67  Issue: 24  Article Number: 244204  DOI: 10.7498/aps.67.20181851  Published: DEC 20 2018  

Abstract: Coherent synthesis of laser pulses is a major trend in the generation of ultrafast pulse field. There is no good way to compensate for the whole spectrum when the spectrum of ultrashort pulses is wide enough to reach an octave, so it is difficult to realize a sub-cycle pulse in a single-path laser system even if the spectrum range is wide enough. In this paper, 0.8 mJ, 30 fs laser pulses at 1 kHz repetition rate with 790 nm center wavelength from a Ti:sapphire chirped pulse amplifier (CPA) system are focused into hollow fiber with an inner diameter of 250 mu m and a length of 1 m to produce an octave-spanning white-light supercontinuum (450-950 nm). Using this supercontinuum, we conduct two sets of comparative experiments. 1) We split the supercontinuum into two pulses with different spectrum ranges (450-750 nm and 650-1000 nm) by a dichroic mirror (HR, 500-700 nm; HT, 700-1000 nm), and we compress the two pulses by the double-chirped mirrors and wedge pairs to generate two few-cycle pulses: the long and short wavelength yielding pulses are 7.9 fs and 6.1 fs, respectively. Then we coherently synthesize two pulses by using another dichroic mirror, and controlling the relative time delay between the two pulses, and thus we synthesize a pulse of 4.1 fs. 2) We directly compress the supercontinuum by the double-chirped mirrors and wedge pairs, and obtain an optimization result of 5.3 fs, of which the pulse duration is wider than that in experiment 1. In these comparative experiments, the advantage of coherent synthesis for shorter pulse duration is preliminarily verified. Besides, the balanced optical cross-correlator technique is used to lock the relative time delay between two pulses. The root-mean-square value of relative time delay drift is less than 80 as in the case with feedback control loop, which ensures the stability of coherent synthesis system. This scheme can be adopted to accurately compensate for the dispersion and obtain the sub-cycle synthesized pulse, which is useful for generating the high harmonic and atto-second pulse.

Accession Number: WOS:000455406800014

Author Identifiers:

ISSN: 1000-3290

Record 4 of 319

Title: Optofluidic twin-core hollow fiber interferometer for label-free sensing of the streptavidin-biotin binding

Author(s): Yang, XH (Yang, Xinghua); Yu, WT (Yu, Wenting); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Zhang, Y (Zhang, Yu); Kong, DP (Kong, Depeng); Long, QL (Long, Qunlong); Yuan, TT (Yuan, Tingting); Cao, JM (Cao, Jiaming); Yuan, LB (Yuan, Libo); Oh, K (Oh, Kyunghwan)

Source: SENSORS AND ACTUATORS B-CHEMICAL  Volume: 277  Pages: 353-359  DOI: 10.1016/j.snb.2018.09.032  Published: DEC 20 2018  

Abstract: We proposed and experimentally demonstrated an optofluidic biosensor using a twin-core hollow optical fiber (TC-HOF) interferometer for label-free sensing of the streptavidin-biotin binding. The TC-HOF had a central hole and two cores were imbedded near its circumference. The central hole functioned as a microfluidic channel where the liquid was flown. One of the cores was suspended at the inner surface of the hole and served as sensing arm while the other core embedded in the cladding as the reference arm, which formed an integrated all-fiber Mach-Zehnder interferometer (MZI). Both ends of TC-HOF were serially spliced to multimode fiber-single mode fiber assembly, whose lateral positions were adjusted to maximize the interference visibility. Before the surface functionalization, the pristine TC-HOF MZI showed the RI sensitivity of 2577 nm/RIU. The suspended core's surface was chemically modified with streptavidin and biotin solutions were injected through micro-HOles in TC-HOF. Through the specific binding reaction between biotin and streptavidin, the effective refractive index (RI) around the sensing arm was modulated, which was detected by the spectral shifts in the interference patterns. The proposed sensor showed an excellent linear response to the biotin concentration in the range of 0.01-0.1 mg/mL and the net detection sensitivity of biotin was 16.9 nm/(mg/mL), which was achieved in a label-free manner. This device can be further applied to sensing and monitoring of the biochemical binding of biotin with various biomolecules such as cells, antigens, antibodies, and DNA in real-time and in situ.

Accession Number: WOS:000453066700044

Author Identifiers:

ISSN: 0925-4005

Record 5 of 319

Title: A CNN-RNN architecture for multi-label weather recognition

Author(s): Zhao, B (Zhao, Bin); Li, XL (Li, Xuelong); Lu, XQ (Lu, Xiaoqiang); Wang, ZG (Wang, Zhigang)

Source: NEUROCOMPUTING  Volume: 322  Pages: 47-57  DOI: 10.1016/j.neucom.2018.09.048  Published: DEC 17 2018  

Abstract: Weather Recognition plays an important role in our daily lives and many computer vision applications. However, recognizing the weather conditions from a single image remains challenging and has not been studied thoroughly. Generally, most previous works treat weather recognition as a single-label classification task, namely, determining whether an image belongs to a specific weather class or not. This treatment is not always appropriate, since more than one weather conditions may appear simultaneously in a single image. To address this problem, we make the first attempt to view weather recognition as a multi-label classification task, i.e., assigning an image more than one labels according to the displayed weather conditions. Specifically, a CNN-RNN based multi-label classification approach is proposed in this paper. The convolutional neural network (CNN) is extended with a channel-wise attention model to extract the most correlated visual features. The Recurrent Neural Network (RNN) further processes the features and excavates the dependencies among weather classes. Finally, the weather labels are predicted step by step. Besides, we construct two datasets for the weather recognition task and explore the relationships among different weather conditions. Experimental results demonstrate the superiority and effectiveness of the proposed approach. The new constructed datasets will be available at https://github.com/wzgwzg/Multi-Label-Weather-Recognition. (C) 2018 Elsevier B.V. All rights reserved.

Accession Number: WOS:000447624800005

Author Identifiers:

ISSN: 0925-2312

eISSN: 1872-8286

Record 6 of 319

Title: Characterizations of a Proposed 3300-V Press-Pack IGBT Module Using Nanosilver Paste for High-Voltage Applications

Author(s): Feng, JJ (Feng, Jingjing); Mei, YH (Mei, Yunhui); Li, XB (Li, Xianbin); Lu, GQ (Lu, Guo-Quan)

Source: IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS  Volume: 6  Issue: 4  Pages: 2245-2253  DOI: 10.1109/JESTPE.2018.2820046  Published: DEC 2018  

Abstract: Nanosilver paste was used in this study as a die-attachment material for 3300-V power chips to eliminate the pressure contact of a press-pack power module. The proposed insulated-gate bipolar transistor (IGBT) module was named as a sinter-pack IGBT module. We studied the effect of the assisted hydrostatic pressure, i.e., 0, 1, 3, 5, and 10 MPa, on the mechanical, thermal, and electrical performance of the as-sintered silver joints. As the pressure increased, the die-shear strength increased, and the thermal impedance decreased, as expected. The electrical properties of the assembly using the sintered silver were comparable with those of the chip with the same power rating, which proved the feasibility of the as-sintered IGBT specimens. The thermal resistance of the sinter-pack IGBT module decreased by 15.8% compared with that of the commercial press-pack one with the same power rating. The static electrical properties of the sinter-pack IGBT module were consistent with those of the commercial press-pack one, which further proved the feasibility of the sinter-pack IGBT module.

Accession Number: WOS:000449092400054

Author Identifiers:

ISSN: 2168-6777

Record 7 of 319

Title: Shape-Preserving Object Depth Control for Stereoscopic Images

Author(s): Lei, JJ (Lei, Jianjun); Peng, B (Peng, Bo); Zhang, CQ (Zhang, Changqing); Mei, XG (Mei, Xuguang); Cao, XC (Cao, Xiaochun); Fan, XT (Fan, Xiaoting); Li, XL (Li, Xuelong)

Source: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY  Volume: 28  Issue: 12  Pages: 3333-3344  DOI: 10.1109/TCSVT.2017.2749146  Published: DEC 2018  

Abstract: In the field of 3-D technology, it is interesting as well as meaningful issue to control object depth in 3-D space. Recently, some depth control methods for stereoscopic images have been proposed, which usually employ depth map or directly process color images to implement depth control. There are two main disadvantages for these methods. First, the results of these methods usually suffer from object deformation and holes. Second, these methods are prone to cause undesired object size changing in 3-D space. To address these issues, we propose a shape-preserving object depth control method for stereoscopic images. First, a novel depth mapping model is presented for calculating the ideal coordinates of the key points in depth control, so that the shape of the object can be well preserved. Afterward, the image content-based constraints are used to further preserve the structure of the object and its background. Finally, the warping technology is introduced to deal with images optimally as well as to avoid holes. Experimental results show that the proposed method can control object depth and preserve the shape of the object effectively without sensible background distortion.

Accession Number: WOS:000452429900002

Author Identifiers:

ISSN: 1051-8215

eISSN: 1558-2205

Record 8 of 319

Title: Biomimetic Anti-adhesive Surface Micro-structures of Electrosurgical Knife Fabricated by Fibre Laser

Author(s): Li, C (Li, Chen); Yang, LJ (Yang, Li-jun); Yan, CC (Yan, Cheng-cheng); Chen, W (Chen, Wei); Cheng, GH (Cheng, Guang-hua)

Source: JOURNAL OF LASER MICRO NANOENGINEERING  Volume: 13  Issue: 3  Pages: 309-313  DOI: 10.2961/jlmn.2018.03.0028  Published: DEC 2018  

Abstract: Electrosurgical knife is the most common invasive surgical instrument in a cutting and hemostasis process, which easily leads the overheated tissues to pyrolysis, eschar and adhesion on the knife surface. In order to minimize the adhesion of the overheated tissues, we investigated and fabricated the surface micro-structures on the blade by fiber laser inspired by shark's skin. The wettability of the blade surfaces with different bionic shark skins were measured by the contact angles, revealing the surface wettability effect. Frictional coefficients between the blade surfaces with different bionic shark skins and pork liver tissues are respectively measured by friction test machine. After cutting the pork liver, the adhesive tissue mass on the electrosurgical knives are weighed to study the anti-adhesion. The relationship between adhesive mass, wettability and frictional coefficients on the bionic shark skins are analyzed in the orthogonal experimental method. The experimental results show that the bionic shark skin on the blades can effectively reduce the adhesive tissues.

Accession Number: WOS:000453263900028

Author Identifiers:

ISSN: 1880-0688

Record 9 of 319

Title: Wideband wavelength-tunable ultrafast fiber laser based on black phosphorus saturable absorber

Author(s): Li, WL (Li, Wenlei); Chen, GW (Chen, Guangwei); Wang, GM (Wang, Guomei); Zeng, C (Zeng, Chao); Zhao, W (Zhao, Wei)

Source: LASER PHYSICS LETTERS  Volume: 15  Issue: 12  Article Number: 125102  DOI: 10.1088/1612-202X/aae786  Published: DEC 2018  

Abstract: We report a wideband wavelength-tunable ultrafast fiber laser mode-locked with a few-layer black phosphorus (BP) saturable absorber. The proposed laser not only delivers picosecond stable conventional solitons but also exhibits flexible wavelength tunability from 1529 to 1592nm. It is experimentally demonstrated that the broadband saturable absorption property of BP and birefringence filtering effects in the cavity contribute significantly to the aforementioned merits. In addition, the round-trip model is established to numerically demonstrate the spectral evolution, and numerical results are in good agreement with experimental observations. The proposed laser system is compact and wavelength-tunable, which provides an efficient solution for applications where a widely tunable ultrafast fiber laser is required.

Accession Number: WOS:000448864700001

Author Identifiers:

ISSN: 1612-2011

eISSN: 1612-202X

Record 10 of 319

Title: SESAM mode-locked all-polarization-maintaining fiber linear cavity ytterbium laser source with spectral filter as pulse shaper

Author(s): Lv, ZG (Lv, Zhiguo); Yang, Z (Yang, Zhi); Li, F (Li, Feng); Yang, XJ (Yang, Xiaojun); Tang, SK (Tang, Shukui); Yang, Y (Yang, Yang); Li, QL (Li, Qianglong); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei)

Source: LASER PHYSICS  Volume: 28  Issue: 12  Article Number: 125103  DOI: 10.1088/1555-6611/aae18b  Published: DEC 2018  

Abstract: We report on a SESAM mode-locked all-normal-dispersion all-polarization-maintaining (PM) ytterbium-doped picosecond fiber laser. The linear cavity oscillator utilizes a narrowband filter for pulse shaping for the first time, to the best of our knowledge. Stable mode-locked pulses with a repetition rate of 29 MHz are achieved under a maximum average output power of 35.9 mW. The linearly polarized pulses have a full width at half maximum of 4nm at a central wavelength of 1032nm, and a 20.6ps pulse duration with pulse energies of 1.2 nJ. Compared to the reported experiment scheme of the generation of the picosecond pulses, the presented all-PM-fiber linear cavity mode-locked oscillator with spectral filter as pulse modulation component provides a new method for the realization of the compact-sized low-cost high-performance picosecond pulses and has important potential applications in a seeding master-oscillator power amplification system.

Accession Number: WOS:000446775100001

Author Identifiers:

ISSN: 1054-660X

eISSN: 1555-6611

Record 11 of 319

Title: The frequency behavior of hysteresis loops in Mn:Fe:KTN ferroelectric single crystal

Author(s): Ma, XG (Ma, Xiangguo); Li, Z (Li, Zhen); Lu, QN (Lu, Qieni); Li, BH (Li, Bihua); Zhang, MD (Zhang, Mingdi)

Source: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS  Volume: 29  Issue: 23  Pages: 20500-20505  DOI: 10.1007/s10854-018-0185-8  Published: DEC 2018  

Abstract: In this paper, the frequency (f) behavior of hysteresis loops in a tetragonal Mn:Fe:KTN crystal is investigated. We have found that the shape of P-E hysteresis loops experiences systemic f-dependent changes from an asymmetric double hysteresis loop to a normal single loop, as the frequency changes from high to low (150-0.01Hz). The shape of P-E loop is strongly f-dependent only at low frequency (f<1Hz) and f-independent at the high one (f10Hz), and the maximum polarization stays unchanged with f varying at the same temperature and amplitude of electric field. The frequency-dependent properties of hysteresis loop stem from the forced vibration of two types of electric dipoles induced by the off-center displacement and the local composition gradient distribution, with different response time to applied electric field. The results are of great value for enhancing device performance and fabricating required devices with specific performance characteristics.

Accession Number: WOS:000448831000097

ISSN: 0957-4522

eISSN: 1573-482X

Record 12 of 319

Title: Weakly Supervised Object Detection via Object-Specific Pixel Gradient

Author(s): Shen, YH (Shen, Yunhang); Ji, RR (Ji, Rongrong); Wang, CH (Wang, Changhu); Li, X (Li, Xi); Li, XL (Li, Xuelong)

Source: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS  Volume: 29  Issue: 12  Pages: 5960-5970  DOI: 10.1109/TNNLS.2018.2816021  Published: DEC 2018  

Abstract: Most existing object detection algorithms are trained based upon a set of fully annotated object regions or bounding boxes, which are typically labor-intensive. On the contrary, nowadays there is a significant amount of imagelevel annotations cheaply available on the Internet. It is hence a natural thought to explore such "weak" supervision to benefit the training of object detectors. In this paper, we propose a novel scheme to perform weakly supervised object localization, termed object-specific pixel gradient (OPG). The OPG is trained by using image-level annotations alone, which performs in an iterative manner to localize potential objects in a given image robustly and efficiently. In particular, we first extract an OPG map to reveal the contributions of individual pixels to a given object category, upon which an iterative mining scheme is further introduced to extract instances or components of this object. Moreover, a novel average and max pooling layer is introduced to improve the localization accuracy. In the task of weakly supervised object localization, the OPG achieves a state-of-the-art 44.5% top-5 error on ILSVRC 2013, which outperforms competing methods, including Oquab et al. and region-based convolutional neural networks on the Pascal VOC 2012, with gains of 2.6% and 2.3%, respectively. In the task of object detection, OPG achieves a comparable performance of 27.0% mean average precision on Pascal VOC 2007. In all experiments, the OPG only adopts the off-the-shelf pretrained CNN model, without using any object proposals. Therefore, it also significantly improves the detection speed, i.e., achieving three times faster compared with the stateof-the-art method.

Accession Number: WOS:000451230100014

PubMed ID: 29993990

Author Identifiers:

ISSN: 2162-237X

eISSN: 2162-2388

Record 13 of 319

Title: Aberration correction for improving the image quality in STED microscopy using the genetic algorithm

Author(s): Wang, LW (Wang, Luwei); Yan, W (Yan, Wei); Li, RZ (Li, Runze); Weng, XY (Weng, Xiaoyu); Zhang, J (Zhang, Jia); Yang, ZG (Yang, Zhigang); Liu, LW (Liu, Liwei); Ye, T (Ye, Tong); Qu, JL (Qu, Junle)

Source: NANOPHOTONICS  Volume: 7  Issue: 12  Pages: 1971-1980  DOI: 10.1515/nanoph-2018-0133  Published: DEC 2018  

Abstract: With a purely optical modulation of fluorescent behaviors, stimulated emission depletion (STED) microscopy allows for far-field imaging with a diffraction-unlimited resolution in theory. The performance of STED microscopy is affected by many factors, of which aberrations induced by the optical system and biological samples can distort the wave front of the depletion beam at the focal plane to greatly deteriorate the spatial resolution and the image contrast. Therefore, aberration correction is imperative for STED imaging, especially for imaging thick specimens. Here, we present a wave front compensation approach based on the genetic algorithm (GA) to restore the distorted laser wave front for improving the quality of STED images. After performing aberration correction on two types of zebrafish samples, the signal intensity and the imaging resolution of STED images were both improved, where the thicknesses were 24 pm and 100 pm in the zebrafish retina sample and the zebrafish embryo sample, respectively. The results showed that the GA-based wave front compensation approach has the capability of correction for both system-induced and sample-induced aberrations. The elimination of aberrations can prompt STED imaging in deep tissues; therefore, STED microscopy can be expected to play an increasingly important role in super-resolution imaging related to the scientific research in biological fields.

Accession Number: WOS:000451084700009

PubMed ID: 32123648

Author Identifiers:

ISSN: 2192-8606

eISSN: 2192-8614

Record 14 of 319

Title: A 20 W, Less-Than-1-kHz Linewidth Linearly Polarized All-Fiber Laser

Author(s): Xue, MY (Xue, Mingyuan); Gao, CX (Gao, Cunxiao); Niu, LQ (Niu, Linquan); Zhu, SL (Zhu, Shaolan); Sun, CD (Sun, Chuandong); Zhang, J (Zhang, Jian); He, HD (He, Haodong)

Source: APPLIED SCIENCES-BASEL  Volume: 8  Issue: 12  Article Number: 2593  DOI: 10.3390/app8122593  Published: DEC 2018  

Abstract: We report a continuous-wave high-output power and narrow-linewidth all-fiber laser at 1550 nm with the master oscillator power amplifier (MOPA) configuration. An all-fiber distributed feedback seed laser was boosted by three cascaded fiber amplifiers. In the experiment, we adopted a large-mode-area (LMA) Er3+:Yb3+-co-doped polarization-maintaining fiber to increase nonlinear thresholds and avoided the broadening of the laser linewidth. A linear-polarization fiber laser with average output power of 20 W, linewidth of 0.88 kHz, and power jitter less than 2% was finally achieved.

Accession Number: WOS:000455145000261

eISSN: 2076-3417

Record 15 of 319

Title: Enhanced four-wave mixing in waveguides integrated with graphene oxide

Author(s): Yang, YY (Yang, Yunyi); Wu, JY (Wu, Jiayang); Xu, XY (Xu, Xingyuan); Liang, Y (Liang, Yao); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Morandotti, R (Morandotti, Roberto); Jia, BH (Jia, Baohua); Moss, DJ (Moss, David J.)

Source: APL PHOTONICS  Volume: 3  Issue: 12  Article Number: 120803  DOI: 10.1063/1.5045509  Published: DEC 2018  

Abstract: We demonstrate enhanced four-wave mixing (FWM) in doped silica waveguides integrated with graphene oxide (GO) layers. Owing to strong mode overlap between the integrated waveguides and GO films that have a high Kerr nonlinearity and low loss, the FWM efficiency of the hybrid integrated waveguides is significantly improved. We perform FWM measurements for different pump powers, wavelength detuning, GO coating lengths, and number of GO layers. Our experimental results show good agreement with theory, achieving up to similar to 9.5-dB enhancement in the FWM conversion efficiency for a 1.5-cm-long waveguide integrated with 2 layers of GO. We show theoretically that for different waveguide geometries an enhancement in FWM efficiency of similar to 20 dB can be obtained in the doped silica waveguides and more than 30 dB in silicon nanowires and slot waveguides. This demonstrates the effectiveness of introducing GO films into integrated photonic devices in order to enhance the performance of nonlinear optical processes. (C) 2018 Author(s).

Accession Number: WOS:000454248200004

Author Identifiers:

ISSN: 2378-0967

Record 16 of 319

Title: Ultrafast camera with MHz repetition rate for 2D time-resolved fluorescence imaging of cells and tissues

Author(s): Ye, W (Ye, Wen); Yang, Y (Yang, Yang); Xu, P (Xu, Peng); Wang, B (Wang, Bo); Zhu, BL (Zhu, Bingli); Cao, WW (Cao, Weiwei); Bai, YL (Bai, Yonglin)

Source: BASIC & CLINICAL PHARMACOLOGY & TOXICOLOGY  Meeting Abstract: 185  Volume: 124  Special Issue: SI  Pages: 116-117  Supplement: 2  Published: DEC 2018  

Accession Number: WOS:000452533800186

Author Identifiers:

ISSN: 1742-7835

eISSN: 1742-7843

Record 17 of 319

Title: Fast and Flexible Large Graph Embedding Based on Anchors

Author(s): Yu, WZ (Yu, Weizhong); Nie, FP (Nie, Feiping); Wang, F (Wang, Fei); Wang, R (Wang, Rong); Li, XL (Li, Xuelong)

Source: IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING  Volume: 12  Issue: 6  Pages: 1465-1475  DOI: 10.1109/JSTSP.2018.2873985  Published: DEC 2018  

Abstract: Dimensionality reduction is one of the most fundamental topic in machine learning. A range of methods focus on dimensionality reduction have been proposed in various areas. Among the unsupervised dimensionality reduction methods, graph-based dimensionality reduction has begun to draw more and more attention due to its effectiveness. However, most existing graph-based methods have high computation complexity, which is not applicable to large-scale problems. To solve this problem, an unsupervised graph-based dimensionality reduction method called fast and flexible large graph embedding (FFLGE) based on anchors is proposed. FFLGE uses an anchor-based strategy to construct an anchor-based graph and design similarity matrix and then perform the dimensionality reduction efficiently. The computational complexity of the proposed FFLGE reduces to O(ndm), where n is the number of samples, d is the number of dimensions and m is the number of anchors. Furthermore, it is interesting to note that locality preserving projection and principal component analysis are two special cases of FFLGE. In the end, the experiments based on several publicly large-scale datasets proves the effectiveness and efficiency of the method proposed.

Accession Number: WOS:000454221700027

Author Identifiers:

ISSN: 1932-4553

eISSN: 1941-0484

Record 18 of 319

Title: Watt-level passively Q-switched and mode-locked Nd:YAG laser with a reflective MoS₂ saturable absorber

Author(s): Zeng, YJ (Zeng, Yingjie); Wang, YG (Wang, Yonggang); Ren, W (Ren, Wei); Wang, HY (Wang, HongYing); Fu, FX (Fu, Fuxing); Wang, X (Wang, Xi); Zheng, QQ (Zheng, Qiqi); Chen, ZD (Chen, Zhendong); Wei, LL (Wei, Lianglei); Yang, XG (Yang, Xiguang); Wang, J (Wang, Jiang)

Source: OPTICS AND LASER TECHNOLOGY  Volume: 108  Pages: 355-359  DOI: 10.1016/j.optlastec.2018.07.003  Published: DEC 2018  

Abstract: A passively Q-switched mode-locked Nd: YAG laser with a reflective molybdenum disulfide (MoS2) saturable absorber (SA) was demonstrated. The MoS2 SA was made by spin-coating the MoS2 nanoplates onto a home-made silver mirror. The modulation depth of the MoS2 SA was measured to be 3.05%. We optimized the laser beam radii in the crystal and on the reflective silver mirror with MoS2 by accurately designing the oscillator cavity. Under an incident pump power of 11 W, we got the maximum average output power as high as 1.06 W with a repetition rate of 94.72 MHz. The experimental results validated the outstanding characteristics of MoS2 SA and its further amplification possibility in high power all-solid-state pulse lasers. (C) 2018 Elsevier Ltd. All rights reserved.

Accession Number: WOS:000443664100042

Author Identifiers:

ISSN: 0030-3992

eISSN: 1879-2545

Record 19 of 319

Title: Dynamical behavior of self-accelerating beams in LiNbO₃ crystal with background illumination

Author(s): Zhang, MZ (Zhang, Meizhi); Zhang, TY (Zhang, Tongyi); Huo, GW (Huo, Guangwen); Zha, XW (Zha, Xinwei); Hui, ZQ (Hui, Zhanqiang); Zhou, H (Zhou, Hua)

Source: APPLIED PHYSICS B-LASERS AND OPTICS  Volume: 124  Issue: 12  Article Number: 236  DOI: 10.1007/s00340-018-7108-5  Published: DEC 2018  

Abstract: We theoretically study the propagations and interactions of an Airy beam, soliton, and nonlinear self-accelerating beam in LiNbO3 crystal modulated by a shorter wavelength background beam. Simulations indicate that the self-accelerating beam and Airy beam can effectively propagate even in self-defocusing media, and the finite-energy Airy beam can generate bright solitons in a self-focusing medium. When two counter-shift Airy beams interact under appropriate conditions, fusion solitons, breathing solitons, and soliton pairs are generated. If we allow a photovoltaic soliton to collide with an Airy beam, X-type waves and soliton deflection occur at a specific phase shift and beam interval. Moreover, we find that the dynamics of two truncated nonlinear self-accelerating beams tend to exhibit straight propagation with attraction and repulsion in the in- and out-of-phase cases, respectively. These results are significant for applications related to optical routing and optical switches.

Accession Number: WOS:000450989200002

Author Identifiers:

ISSN: 0946-2171

eISSN: 1432-0649

Record 20 of 319

Title: High Resolution and Fast Processing of Spectral Reconstruction in Fourier Transform Imaging Spectroscopy

Author(s): Zhang, WK (Zhang, Weikang); Wen, DS (Wen, Desheng); Song, ZX (Song, Zongxi); Wei, X (Wei, Xin); Liu, G (Liu, Gang); Li, ZX (Li, Zhixin)

Source: SENSORS  Volume: 18  Issue: 12  Article Number: 4159  DOI: 10.3390/s18124159  Published: DEC 2018  

Abstract: High-resolution spectrum estimation has continually attracted great attention in spectrum reconstruction based on Fourier transform imaging spectroscopy (FTIS). In this paper, a parallel solution for interference data processing using high-resolution spectrum estimation is proposed to reconstruct the spectrum in a fast high-resolution way. In batch processing, we use high-performance parallel-computing on the graphics processing unit (GPU) for higher efficiency and lower operation time. In addition, a parallel processing mechanism is designed for our parallel algorithm to obtain higher performance. At the same time, other solving algorithms for the modern spectrum estimation model are introduced for discussion and comparison. We compare traditional high-resolution solving algorithms running on the central processing unit (CPU) and the parallel algorithm on the GPU for processing the interferogram. The experimental results illustrate that runtime is reduced by about 70% using our parallel solution, and the GPU has a great advantage in processing large data and accelerating applications.

Accession Number: WOS:000454817100078

PubMed ID: 30486414

Author Identifiers:

eISSN: 1424-8220

Record 21 of 319

Title: Dynamical stochastic resonance for non-uniform illumination image enhancement

Author(s): Zhang, YB (Zhang, Yongbin); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu)

Source: IET IMAGE PROCESSING  Volume: 12  Issue: 12  Pages: 2147-2152  DOI: 10.1049/iet-ipr.2018.5634  Published: DEC 2018  

Abstract: Images taken under poor illumination conditions have low contrast and dark tones. General dark image enhancement algorithms cannot effectively enhance these images without introducing over-enhancement, detail loss, and noise amplification. In this study, a simple and fast enhancement technique of non-uniform illumination images is proposed based on dynamical stochastic resonance (DSR). The low-contrast images are enhanced through the nonlinear iteration by solving monostable Langevin equation. Iteration parameters are dynamically adjusted according to the intensity distribution of the original images, which ensure the balance of visibility and naturalness in the entire areas. A threshold is defined to automatically confirm the optimal outputs. The enhanced image is obtained by fusing the DSR result, original component, and illumination compensation component. The computational time, no-reference perceptual quality assessment, and lightness order error are measured to evaluate the performance of experimental results. The subjective and objective comparison with state-of-the-art methods shows that our method performs well to enhance the non-uniform illumination images with a low-computational complexity.

Accession Number: WOS:000451759800002

Author Identifiers:

ISSN: 1751-9659

eISSN: 1751-9667

Record 22 of 319

Title: Feature Fusion Information Statistics for feature matching in cluttered scenes

Author(s): Zhou, W (Zhou, Wei); Ma, CW (Ma, Caiwen); Liao, SH (Liao, Shenghui); Shi, JJ (Shi, Jinjing); Yao, T (Yao, Tong); Chang, P (Chang, Peng); Kuijper, A (Kuijper, Arjan)

Source: COMPUTERS & GRAPHICS-UK  Volume: 77  Pages: 50-64  DOI: 10.1016/j.cag.2018.09.012  Published: DEC 2018  

Abstract: Object recognizing in cluttered scenes remains a largely unsolved problem, especially when applying feature matching to cluttered scenes there are many feature mismatches between the scenes and models. We propose our Feature Fusion Information Statistics (FFIS) as the calculation framework for extracting salient information from a Local Surface Patch (LSP) by a Local Reference Frame (LRF). Our LRF is defined on each LSP by projecting the scatter matrix's eigenvectors to a plane which is perpendicular to the normal of the LSP. Based on this, our FFIS descriptor of each LSP is calculated, for which we use the combined distribution of mesh and point information in a local domain. Finally, we evaluate the speed, robustness and descriptiveness of our FFIS with the state-of-the-art methods on several public benchmarks. Our experiments show that our FFIS is fast and obtains a more reliable matching rate than other approaches in cluttered situations. (C) 2018 Elsevier Ltd. All rights reserved.

Accession Number: WOS:000455063200009

Author Identifiers:

ISSN: 0097-8493

eISSN: 1873-7684

Record 23 of 319

Title: A highly efficient magnetically confined ion source for real time on-line monitoring of trace compounds in ambient air

Author(s): Tang, J (Tang, Jie); Ding, XL (Ding, Xuelu); Zhang, P (Zhang, Pei); Lei, BY (Lei, Bingying); Zhao, ZJ (Zhao, Zhongjun); Duan, YX (Duan, Yixiang)

Source: CHEMICAL COMMUNICATIONS  Volume: 54  Issue: 92  Pages: 12962-12965  DOI: 10.1039/c8cc05360j  Published: NOV 28 2018  

Abstract: We fabricate a high-efficient ion source for real time on-line monitoring of trace compounds in ambient air by introducing a weak longitudinal magnetic field to a micro-fabricated DC glow discharge. Mass spectrometric detection of various samples indicates that the signal intensity increases by an order of magnitude and the limit of detection can be lowered to 1/10 of the original level. This improvement results from the increasing ion transport efficiency through the magnetic confinement.

Accession Number: WOS:000450435700011

PubMed ID: 30382248

Author Identifiers:

ISSN: 1359-7345

eISSN: 1364-548X

Record 24 of 319

Title: Spectral clustering based on iterative optimization for large-scale and high-dimensional data

Author(s): Zhao, Y (Zhao, Yang); Yuan, Y (Yuan, Yuan); Nie, FP (Nie, Feiping); Wang, Q (Wang, Qi)

Source: NEUROCOMPUTING  Volume: 318  Pages: 227-235  DOI: 10.1016/j.neucom.2018.08.059  Published: NOV 27 2018  

Abstract: Spectral graph theoretic methods have been a fundamental and important topic in the field of manifold learning and it has become a vital tool in data clustering. However, spectral clustering approaches are limited by their computational demands. It would be too expensive to provide an optimal approximation for spectral decomposition in dealing with large-scale and high-dimensional data sets. On the other hand, the rapid development of data on the Web has posed many rising challenges to the traditional single-task clustering, while the multi-task clustering provides many new thoughts for real-world applications such as video segmentation. In this paper, we will study a Spectral Clustering based on Iterative Optimization (SCIO), which solves the spectral decomposition problem of large-scale and high-dimensional data sets and it well performs on multi-task clustering. Extensive experiments on various synthetic data sets and real-world data sets demonstrate that the proposed method provides an efficient solution for spectral clustering. (C) 2018 Elsevier B.V. All rights reserved.

Accession Number: WOS:000445763500021

Author Identifiers:

ISSN: 0925-2312

eISSN: 1872-8286

Record 25 of 319

Title: All-optical imaging and tracking technology for rectilinear motion targets through scattering media

Author(s): Jia, H (Jia Hui); Luo, XJ (Luo Xiu-Juan); Zhang, Y (Zhang Yu); Lan, FY (Lan Fu-Yang); Liu, H (Liu Hui); Chen, ML (Chen Ming-Lai)

Source: ACTA PHYSICA SINICA  Volume: 67  Issue: 22  Article Number: 224202  DOI: 10.7498/aps.67.20180955  Published: NOV 20 2018  

Abstract: Light scattering is a main factor that restricts optical transmission and deteriorates optical imaging performance. All-optical imaging for moving targets through complex scattering media is one of the most challenging techniques. In this paper, a method for real-time tracking of moving targets through scattering medium is presented by utilizing optical memory-effect and autocorrelation of speckle difference. In the experiment on imaging through a scattering medium, an object is hidden at a distance u behind a highly scattering medium. The object is illuminated by a spatially incoherent pseudothermal light source. The light is diffused through the scattering medium. Camera placed at a distance u(0) on the other side of the medium records the pattern of the scattered light. According to the theory of optical memory-effect, the process of scattering imaging is a convolution process of point spread function (PSF) and object. In the procedure of object moving, the scattered signals from two frames are captured. The background noise could be removed by subtracting the two captured image. Then, the autocorrelation operation calculates the speckle difference, and hidden targets can be effectively reconstructed with the phase retrieval algorithm. The experiment demonstrates the imaging of targets with different speeds. The results have shown that the faster the speed, the worse the imaging quality is. High-speed moving objects can be imaged by using a high frame rate camera to reduce the exposure time or by disambiguating the speckle pattern. In subsequent experiments, the distance of the target movement is calculated with the magnification of the system. The collected two frames of speckle must be within the same memory effect angle. Only in this way can the calculation accuracy of the motion distance be guaranteed. With the moving of the target, the cross-correlation information of the target appears at different positions of the speckle difference autocorrelation map. Finally, according to the cross-correlation of the target at different locations, the real-time tracking of the moving target can be realized. Due to the Gaussian distribution of the laser beam, the cross-correlation intensity of the speckle difference autocorrelation map decreases with the object moving further. Therefore the target moving range is limited by the laser beam diameter, intensity distribution and camera field angle. It is verified experimentally that the imaging and tracking of moving targets which are hidden behind the ground glass can be achieved successfully by using this method. This kind of imaging and real-time tracking technology for targets moving through the scattering medium has important potential applications in biomedicine and other fields.

Accession Number: WOS:000455402400012

ISSN: 1000-3290

Record 26 of 319

Title: Customizing supercontinuum generation via on-chip adaptive temporal pulse-splitting

Author(s): Wetzel, B (Wetzel, Benjamin); Kues, M (Kues, Michael); Roztocki, P (Roztocki, Piotr); Reimer, C (Reimer, Christian); Godin, PL (Godin, Pierre-Luc); Rowley, M (Rowley, Maxwell); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Viktorov, EA (Viktorov, Evgeny A.); Moss, DJ (Moss, David J.); Pasquazi, A (Pasquazi, Alessia); Peccianti, M (Peccianti, Marco); Morandotti, R (Morandotti, Roberto)

Source: NATURE COMMUNICATIONS  Volume: 9  Article Number: 4884  DOI: 10.1038/s41467-018-07141-w  Published: NOV 20 2018  

Abstract: Modern optical systems increasingly rely on complex physical processes that require accessible control to meet target performance characteristics. In particular, advanced light sources, sought for, for example, imaging and metrology, are based on nonlinear optical dynamics whose output properties must often finely match application requirements. However, in these systems, the availability of control parameters (e.g., the optical field shape, as well as propagation medium properties) and the means to adjust them in a versatile manner are usually limited. Moreover, numerically finding the optimal parameter set for such complex dynamics is typically computationally intractable. Here, we use an actively controlled photonic chip to prepare and manipulate patterns of femtosecond optical pulses that give access to an enhanced parameter space in the framework of supercontinuum generation. Taking advantage of machine learning concepts, we exploit this tunable access and experimentally demonstrate the customization of nonlinear interactions for tailoring supercontinuum properties.

Accession Number: WOS:000450580600001

PubMed ID: 30459363

Author Identifiers:

ISSN: 2041-1723

Record 27 of 319

Title: Three-dimensions thermal model of a high-power diode laser bar

Author(s): Wu, DH (Wu, Di-Hai); Zah, CE (Zah, Chung-En); Liu, XS (Liu, Xingsheng)

Source: APPLIED OPTICS  Volume: 57  Issue: 33  Pages: 9868-9876  DOI: 10.1364/AO.57.009868  Published: NOV 20 2018  

Abstract: An analytical, three-dimensional, steady-state thermal model of a high-power diode laser bar is presented in this paper. The heat spreading angle in a laser bar heat sink, subjected to several convective conditions on the bottom-side, was calculated with this model. Thermal design curves for the heat sink and submount are also presented. Special discussion is presented for two kinds of our conduction-cooled laser bars. Finite element simulation and experimental results based on the wavelength shift method are compared with this analytical solution. The familiar 45 degrees angle in thermal design for a commercial hard solder conduction-cooled laser bar was found to lead to a 12% increase in thermal resistance relative to a free lateral diffusion heat sink. (C) 2018 Optical Society of America

Accession Number: WOS:000450620700021

PubMed ID: 30462024

Author Identifiers:

ISSN: 1559-128X

eISSN: 2155-3165

Record 28 of 319

Title: Sub-wavelength focusing based on all-dielectric polarization-independent metalens

Author(s): Zhao, W (Zhao, Wei); Li, XY (Li, Xingyi); Li, SQ (Li, Siqi); Ge, ZQ (Ge, Zhiqiang); Liu, ML (Liu, Mulong); Li, ZY (Li, Zhongyu); Du, SJ (Du, Shujian)

Source: INTERNATIONAL JOURNAL OF MODERN PHYSICS B  Volume: 32  Issue: 29  Article Number: 1850321  DOI: 10.1142/S0217979218503216  Published: NOV 20 2018  

Abstract: We have proposed an all-dielectric polarization-independent metalens, which can be used for sub-wavelength focusing. The phase discontinuity of transmission light is produced by varying the diameter of the nanopillar. In this way, the incident light can be focused into sub-wavelength spot. Besides, finite-difference time-domain results show that near diffraction limit focusing is realized for the wavelength from 580 nm to 750 nm, which means the proposed metalens possesses a broad operation bandwidth. This all-dielectric metalens features polarization independent and broad bandwidth, and thus promises great potential for the applications of nanolithography, dense storage and biophotonics.

Accession Number: WOS:000451225000004

Author Identifiers:

ISSN: 0217-9792

eISSN: 1793-6578

Record 29 of 319

Title: Action recognition using spatial-optical data organization and sequential learning framework

Author(s): Yuan, Y (Yuan, Yuan); Zhao, Y (Zhao, Yang); Wang, Q (Wang, Qi)

Source: NEUROCOMPUTING  Volume: 315  Pages: 221-233  DOI: 10.1016/j.neucom.2018.06.071  Published: NOV 13 2018  

Abstract: Recognizing human actions in videos is a challenging problem owning to complex motion appearance, various backgrounds and semantic gap between low-level features and high-level semantics. Existing methods have scored some achievements and many new thoughts have been proposed for action recognition. They focus on designing a robust feature description and training an elaborate learning model, and many of them can benefit from a two-stream network with a stack of RGB frames and optical flow frames. However, these features for human action representation are struggling with the limited feature representation as RGB videos are confused by static appearance redundancy and optical flow videos cannot represent the detailed appearance. To solve these problems, we propose an efficient algorithm based on the spatial-optical data organization and the sequential learning framework. There are two contributions of our method: a novel data organization based on hierarchical weighting segmentation and optical flow for video representation, and a lightweight deep learning model based on the Convolutional 3D (C3D) network and the Recurrent Neural Network (RNN) for complicated action recognition. The new data organization aggregates the merits of motion appearance, movement trajectories and optical flow in a creative way to highlight the meaningful information. And the proposed lightweight model has an insight into patterns and semantics of sequential data by low-level spatiotemporal feature extraction and high-level information mining. The proposed method is evaluated on the state-of-the-art dataset and the results demonstrate that our method have a good performance for complex human action recognition. (c) 2018 Elsevier B.V. All rights reserved.

Accession Number: WOS:000445934400022

Author Identifiers:

ISSN: 0925-2312

eISSN: 1872-8286

Record 30 of 319

Title: Patient-specific ECG classification by deeper CNN from generic to dedicated

Author(s): Li, YZ (Li, Yazhao); Pang, YW (Pang, Yanwei); Wang, J (Wang, Jian); Li, XL (Li, Xuelong)

Source: NEUROCOMPUTING  Volume: 314  Pages: 336-346  DOI: 10.1016/j.neucom.2018.06.068  Published: NOV 7 2018  

Abstract: This paper presents a new mechanism which is more effective for wearable devices to classify patient-specific electrocardiogram (ECG) heartbeats. In our method, a Generic Convolutional Neural Network (GCNN) is trained first using a large number of heartbeats without distinguishing patients. Based on the GCNN, fine-tuning technique is applied to modify the GCNN to a Tuned Dedicated CNN (TDCNN) for the corresponding individual. Notably, only the GCNN instead of common training data is required to be stored into wearable devices. Moreover, only fine-tuning with several seconds rather than dozens of minutes is needed before the TDCNN is used to monitor the long-term ECG signals in clinical. To accelerate the ECG classification, only the original ECG heartbeat is input to the CNN without other extended information from the neighbor heartbeats or FFT representation. A deeper CNN architecture with small-scale convolutional kernels is adopted to improve the speed and accuracy for classification. With deeper CNN, hierarchical features can be extracted to help improve the accuracy of ECG classification. The state-of-the-art performance on efficiency and accuracy for ECG classification over MIT-BIH dataset is achieved by the proposed method. The effectiveness and superiority for detecting ventricular ectopic beats (VEB) and supraventricular ectopic beats (SVEB) events are demonstrated. The proposed mechanism of fine-tuning the GCNN to TDCNN improves the efficiency for training patient-specific CNN classifier. Because of the computational efficiency of fine-tuning, ECG diagnosis and heart monitoring can be easily implemented with popular wearable devices in practice. (C) 2018 Elsevier B.V. All rights reserved.

Accession Number: WOS:000443718400033

Author Identifiers:

ISSN: 0925-2312

eISSN: 1872-8286

Record 31 of 319

Title: Ultrafast soliton and stretched-pulse switchable mode-locked fiber laser with hybrid structure of multimode fiber based saturable absorber

Author(s): Zhao, FY (Zhao, Fengyan); Wang, YS (Wang, Yishan); Wang, HS (Wang, Hushan); Yan, ZJ (Yan, Zhijun); Hu, XH (Hu, Xiaohong); Zhang, W (Zhang, Wei); Zhang, T (Zhang, Ting); Zhou, KM (Zhou, Kaiming)

Source: SCIENTIFIC REPORTS  Volume: 8  Article Number: 16369  DOI: 10.1038/s41598-018-34762-4  Published: NOV 6 2018  

Abstract: We demonstrate an all-fiber mode locked laser based on hybrid structure of multimode fiber saturable absorber (SA) that can realize both conventional soliton and stretched-pulse states. Stable 16.44 MHz conventional soliton pulses are achieved by injecting 80 mW threshold pump power. By increasing the incident pump power to 420 mW, the laser evolves from soliton operation into stretched-pulse mode locking state. 310 fs stretched-pulse are obtained with the same repetition rate as the soliton pulses. The center wavelength and its 3 dB spectrum bandwidth are 1603 nm and 14.2 nm, respectively. For the first time, we experimentally confirm transition between conventional soliton and stretched-pulse in 1.5 mu m mode-locked fiber laser by introducing multimode optical fiber SA. Moreover, the maximum single pulse energy of nearly 1 nJ is achieved. Such all-fiber mode-locked lasers based on hybrid structure of multimode fiber are attractive for practical applications without damage and the limitation of life time.

Accession Number: WOS:000449274000002

PubMed ID: 30401821

Author Identifiers:

ISSN: 2045-2322

Record 32 of 319

Title: Attosecond relative delay measurement using transient-grating frequency-resolved optical grating

Author(s): Huang, P (Huang Pei); Fang, SB (Fang Shao-Bo); Huang, HD (Huang Hang-Dong); Zhao, K (Zhao Kun); Teng, H (Teng Hao); Hou, X (Hou Xun); Wei, ZY (Wei Zhi-Yi)

Source: ACTA PHYSICA SINICA  Volume: 67  Issue: 21  Article Number: 214202  DOI: 10.7498/aps.67.20181570  Published: NOV 5 2018  

Abstract: The accurate and precise controlling of the attosecond time delay between the sub-pulses within a hundredth of an optical cycle is the key ingredient for the sophisticated custom-tailored coherent waveform synthesizer. The attosecond delay control technique commonly experiences the "complete" characterization of the ultrashort sub-cycle pulses, which includes the spatiotemporal pulse characterization of the synthesized waveform and the attosecond relative delay between the parent pulses. In this work, the relative time delay between spectrally separated ultrashort parent pulses is characterized in an interferometer scheme with a background-free transient-grating frequency-resolved optical grating (TG-FROG). The TG-FROG geometry accurately measures the full time-dependent intensity and phase of ultrashort laser pulses in a wide range of regime (from ultraviolet to infrared) and offers significant advantages over other nonlinear-optical processes geometries (i.e., the polarization-gate-FROG, the self-diffraction-FROG, the second-harmonic generation-FROG and the third-harmonic-generation-FROG). The attosecond measurement accuracy is achieved for the first time, to the best of our knowledge. In this experiment, the output of a carrier-envelope-phase-stable Ti:sapphire amplifier (sub-30-fs, over-l-mJ, 1 kHz) is spectrally broadened in a neon-filled hollow-core fiber with an inner diameter of 250 mu m. The transmission through the pressure-gradient hollow-core fiber results in an mJ-level octave-spanning white-light supercontinuum, supporting a sub-3-fs Fourier transform-limited pulse. The supercontinuum is spectrally divided into two parent pulses by using a dichroic mirror. The sub-pulses are individually compressed by the custom-designed double-chirped mirrors and wedge pairs. The short and long wavelength pulses are separately compressed in few-cycle regime, yielding pulses with 6.7 fs and 9.8 fs, respectively. This technique overcomes the bottlenecks in the traditional delay measurement and should be applicable for many ultra-broadband pulse characterizations with extremely simple and alignment-free delay control device used. Furthermore, this new method will be easily adapted for the ultra-broadband two-dimensional electronic spectroscopy, the advanced temporal cloaking, and the field of sub-cycle arbitrary coherent waveform synthesizer for controlling strong-field interactions in atoms, molecules, solids, and nanostructures. We foresee that in the near future this novel technology will be very attractive for various applications in the next-generation light sources such as the Synergetic Extreme Condition User Facility in Beijing, China.

Accession Number: WOS:000449700800013

Author Identifiers:

ISSN: 1000-3290

Record 33 of 319

Title: Iterative Filtering and Structural Features for Hyperspectral Image Classification with Limited Samples

Author(s): Wang, WN (Wang, Wenning); Liu, XB (Liu, Xuebin); Mou, XQ (Mou, Xuanqin); Sun, L (Sun, Li)

Source: CANADIAN JOURNAL OF REMOTE SENSING  Volume: 44  Issue: 6  Pages: 575-587  DOI: 10.1080/07038992.2019.1572500  Published: NOV 2 2018  

Abstract: Hyperspectral classification with limited training samples is challenging. The current work lies in two aspects: first, we change the statistical distribution of samples by iterative filtering based on the guide images. The filter is called a Simplified Bilateral Filter (SBF), which is a modified bilateral filter for clustering samples. Secondly, new structural convolution kernels are used to generate new hyperspectral data. Finally, the class label of the test sample after dimension reduction is determined by OMP classification or SVM classification. Experimental results on two hyperspectral datasets demonstrate the effectiveness of the proposed feature extraction method in improving classification accuracy with limited training samples.

Accession Number: WOS:000463914400002

ISSN: 0703-8992

eISSN: 1712-7971

Record 34 of 319

Title: Approximate Low-Rank Projection Learning for Feature Extraction

Author(s): Fang, XZ (Fang, Xiaozhao); Han, N (Han, Na); Wu, JG (Wu, Jigang); Xu, Y (Xu, Yong); Yang, J (Yang, Jian); Wong, WK (Wong, Wai Keung); Li, XL (Li, Xuelong)

Source: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS  Volume: 29  Issue: 11  Pages: 5228-5241  DOI: 10.1109/TNNLS.2018.2796133  Published: NOV 2018  

Abstract: Feature extraction plays a significant role in pattern recognition. Recently, many representation-based feature extraction methods have been proposed and achieved successes in many applications. As an excellent unsupervised feature extraction method, latent low-rank representation (LatLRR) has shown its power in extracting salient features. However, LatLRR has the following three disadvantages: 1) the dimension of features obtained using LatLRR cannot be reduced, which is not preferred in feature extraction; 2) two low-rank matrices are separately learned so that the overall optimality may not be guaranteed; and 3) LatLRR is an unsupervised method, which by far has not been extended to the supervised scenario. To this end, in this paper, we first propose to use two different matrices to approximate the low-rank projection in LatLRR so that the dimension of obtained features can be reduced, which is more flexible than original LatLRR. Then, we treat the two low-rank matrices in LatLRR as a whole in the process of learning. In this way, they can be boosted mutually so that the obtained projection can extract more discriminative features. Finally, we extend LatLRR to the supervised scenario by integrating feature extraction with the ridge regression. Thus, the process of feature extraction is closely related to the classification so that the extracted features are discriminative. Extensive experiments are conducted on different databases for unsupervised and supervised feature extraction, and very encouraging results are achieved in comparison with many state-of-the-arts methods.

Accession Number: WOS:000447832200005

PubMed ID: 29994377

Author Identifiers:

ISSN: 2162-237X

eISSN: 2162-2388

Record 35 of 319

Title: CNNs-Based RGB-D Saliency Detection via Cross-View Transfer and Multiview Fusion

Author(s): Han, JW (Han, Junwei); Chen, H (Chen, Hao); Liu, N (Liu, Nian); Yan, CG (Yan, Chenggang); Li, XL (Li, Xuelong)

Source: IEEE TRANSACTIONS ON CYBERNETICS  Volume: 48  Issue: 11  Pages: 3171-3183  DOI: 10.1109/TCYB.2017.2761775  Published: NOV 2018  

Abstract: Salient object detection from RGB-D images aims to utilize both the depth view and RGB view to automatically localize objects of human interest in the scene. Although a few earlier efforts have been devoted to the study of this paper in recent years, two major challenges still remain: 1) how to leverage the depth view effectively to model the depth-induced saliency and 2) how to implement an optimal combination of the RGB view and depth view, which can make full use of complementary information among them. To address these two challenges, this paper proposes a novel framework based on convolutional neural networks (CNNs), which transfers the structure of the RGB-based deep neural network to be applicable for depth view and fuses the deep representations of both views automatically to obtain the final saliency map. In the proposed framework, the first challenge is modeled as a cross-view transfer problem and addressed by using the task-relevant initialization and adding deep supervision in hidden layer. The second challenge is addressed by a multiview CNN fusion model through a combination layer connecting the representation layers of RGB view and depth view. Comprehensive experiments on four benchmark datasets demonstrate the significant and consistent improvements of the proposed approach over other state-of-the-art methods.

Accession Number: WOS:000447825400013

PubMed ID: 29990092

Author Identifiers:

ISSN: 2168-2267

eISSN: 2168-2275

Record 36 of 319

Title: Few-shot decision tree for diagnosis of ultrasound breast tumor using BI-RADS features

Author(s): Huang, QH (Huang, Qinghua); Zhang, F (Zhang, Fan); Li, XL (Li, Xuelong)

Source: MULTIMEDIA TOOLS AND APPLICATIONS  Volume: 77  Issue: 22  Pages: 29905-29918  DOI: 10.1007/s11042-018-6026-1  Published: NOV 2018  

Abstract: This paper proposes an ultrasound breast tumor CAD system based on BI-RADS features scoring and decision tree algorithm. Because of the difficulty of biopsy label collection, the proposed system adopts a few-shot learning method. The SVM classifier is employed to preliminarily mark the unlabeled cases firstly. Then these unlabeled cases with the pseudo labels are combined with the few real-labeled cases to train the decision tree. To test the performance of the proposed method, 1208 ultrasound breast images were collected, and three well-experienced clinicians and three interns evaluated these images according to the BI-RADS scoring scheme. All of the images are transformed into vectors such that the algorithm can process. The experimental results show that the system performance improves significantly with the help of pseudo-labeled data. Compared to the decision tree trained by the real-labeled cases only, when the number of real-labeled cases was 40, the accuracy, specificity, sensitivity of the proposed system were increased by 2.05%, 2.47% and 1.81%, respectively; the positive predictive value (PPV) and the negative predictive value (NVP) were increased by 1.29% and 3.05%, respectively. Meanwhile, the performance of the proposed method was the same as the method using sufficient samples. When the number of the labeled cases reached 100, the accuracy, specificity, sensitivity, PPV and NVP of the proposed method were 90.03%, 87.02%, 91.68%, 93.07%, and 85.03%, respectively. The results demonstrate that our method can efficiently distinguish the breast tumor although the labeled data is not sufficient.

Accession Number: WOS:000451780800041

Author Identifiers:

ISSN: 1380-7501

eISSN: 1573-7721

Record 37 of 319

Title: Discovery of trading points based on Bayesian modeling of trading rules

Author(s): Huang, QH (Huang, Qinghua); Kong, ZF (Kong, Zhoufan); Li, YS (Li, Yanshan); Yang, J (Yang, Jie); Li, XL (Li, Xuelong)

Source: WORLD WIDE WEB-INTERNET AND WEB INFORMATION SYSTEMS  Volume: 21  Issue: 6  Pages: 1473-1490  DOI: 10.1007/s11280-018-0534-9  Published: NOV 2018  

Abstract: Mining hidden patterns with different technical indicators from the historical financial data has been regarded as an efficient way to determine the trading decisions in the financial market. Technical analysis has shown that a number of specific combinations of technical indicators could be treated as trading patterns for forecasting efficient trading directions. However, it is a challenging assignment to discover those combinations. In this paper, we innovatively propose to use a biclustering algorithm to detect the trading patterns. The discovered trading patterns are then utilized to forecast the market movement based on the Naive Bayesian algorithm. Finally, the Adaboost algorithm is applied to improve the accuracy of the forecasts. The proposed method was implemented on seven historical stock datasets and the average performance was compared with that of four existing algorithms. Experimental results demonstrated that the proposed algorithm outperforms the other four algorithms and can provide a valuable reference in the financial investments.

Accession Number: WOS:000449485200003

Author Identifiers:

ISSN: 1386-145X

eISSN: 1573-1413

Record 38 of 319

Title: A new breast tumor ultrasonography CAD system based on decision tree and BI-RADS features

Author(s): Huang, QH (Huang, Qinghua); Zhang, F (Zhang, Fan); Li, XL (Li, Xuelong)

Source: WORLD WIDE WEB-INTERNET AND WEB INFORMATION SYSTEMS  Volume: 21  Issue: 6  Pages: 1491-1504  DOI: 10.1007/s11280-017-0522-5  Published: NOV 2018  

Abstract: In this paper, we present a novel computer-aided diagnostic (CAD) system based on the Breast Imaging Reporting and Data System (BI-RADS) terminology scores of screening ultrasonography (US). The decision tree algorithm is adopted to analyze the BI-RADS information to differentiate between the malignant and benign breast tumors. Although many ultrasonography CAD systems have been developed for decades, there are still some problems in clinical practice. Previous CAD systems are opaque for clinicians and cannot process the ultrasound image from different ultrasound machines. This study proposes a novel CAD system utilizing BI-RADS scoring standard and Classification and Regression Tree (CART) algorithm to overcome the two problems. The original dataset consists of 1300 ultrasound breast images. Three well-experienced clinicians evaluated all of the images according to the BI-RADS feature scoring standard. Subsequently, each image could be transformed into a 25x1 vector. The CART algorithm was finally used to classify these vectors. In the experiments, we used the oversampling method to balance the number of malignant samples and benign samples. The 5-fold cross validation was employed to evaluate the performance of the system. The accuracy reached 94.58%, the specificity was 98.84%, the sensitivity was 90.80%, the positive predictive value (PPV) was 98.91% and the negative predictive value (NVP) was 90.56%. The experiment results show that the proposed system can obtain a sufficient performance in the breast diagnosis and can effectively recognize the benign breast tumors in BI-RADS 3.

Accession Number: WOS:000449485200004

Author Identifiers:

ISSN: 1386-145X

eISSN: 1573-1413

Record 39 of 319

Title: Discriminative and Orthogonal Subspace Constraints-Based Nonnegative Matrix Factorization

Author(s): Li, XL (Li, Xuelong); Cui, GS (Cui, Guosheng); Dong, YS (Dong, Yongsheng)

Source: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY  Volume: 9  Issue: 6  Article Number: 65  DOI: 10.1145/3229051  Published: NOV 2018  

Abstract: Nonnegative matrix factorization (NMF) is one widely used feature extraction technology in the tasks of image clustering and image classification. For the former task, various unsupervised NMF methods based on the data distribution structure information have been proposed. While for the latter task, the label information of the dataset is one very important guiding. However, most previous proposed supervised NMF methods emphasis on imposing the discriminant constraints on the coefficient matrix. When dealing with new coming samples, the transpose or the pseudoinverse of the basis matrix is used to project these samples to the low dimension space. In this way, the label influence to the basis matrix is indirect. Although, there are also some methods trying to constrain the basis matrix in NMF framework, either they only restrict within-class samples or impose improper constraint on the basis matrix. To address these problems, in this article a novel NMF framework named discriminative and orthogonal subspace constraints-based nonnegative matrix factorization (DOSNMF) is proposed. In DOSNMF, the discriminative constraints are imposed on the projected subspace instead of the directly learned representation. In this manner, the discriminative information is directly connected with the projected subspace. At the same time, an orthogonal term is incorporated in DOSNMF to adjust the orthogonality of the learned basis matrix, which can ensure the orthogonality of the learned subspace and improve the sparseness of the basis matrix at the same time. This framework can be implemented in two ways. The first way is based on the manifold learning theory. In this way, two graphs, i.e., the intrinsic graph and the penalty graph, are constructed to capture the intra-class structure and the inter-class distinctness. With this design, both the manifold structure information and the discriminative information of the dataset are utilized. For convenience, we name this method as the name of the framework, i.e., DOSNMF. The second way is based on the Fisher's criterion, we name it Fisher's criterion-based DOSNMF (FDOSNMF). The objective functions of DOSNMF and FDOSNMF can be easily optimized using multiplicative update (MU) rules. The new methods are tested on five datasets and compared with several supervised and unsupervised variants of NMF. The experimental results reveal the effectiveness of the proposed methods.

Accession Number: WOS:000455480700005

Author Identifiers:

ISSN: 2157-6904

eISSN: 2157-6912

Record 40 of 319

Title: Multi-modal gated recurrent units for image description

Author(s): Li, XL (Li, Xuelong); Yuan, AH (Yuan, Aihong); Lu, XQ (Lu, Xiaoqiang)

Source: MULTIMEDIA TOOLS AND APPLICATIONS  Volume: 77  Issue: 22  Pages: 29847-29869  DOI: 10.1007/s11042-018-5856-1  Published: NOV 2018  

Abstract: Using a natural language sentence to describe the content of an image is a challenging but very important task. It is challenging because a description must not only capture objects contained in the image and the relationships among them, but also be relevant and grammatically correct. In this paper a multi-modal embedding model based on gated recur-rent units (GRU) which can generate variable-length description for a given image. In the training step, we apply the convolutional neural network (CNN) to extract the image feature. Then the feature is imported into the multi-modal GRU as well as the corresponding sentence representations. The multi-modal GRU learns the inter-modal relations between image and sentence. And in the testing step, when an image is imported to our multi-modal GRU model, a sentence which describes the image content is generated. The experimental results demonstrate that our multi-modal GRU model obtains the state-of-the-art performance on Flickr8K, Flickr30K and MS COCO datasets.

Accession Number: WOS:000451780800038

Author Identifiers:

ISSN: 1380-7501

eISSN: 1573-7721

Record 41 of 319

Title: Structurally Incoherent Low-Rank Nonnegative Matrix Factorization for Image Classification

Author(s): Lu, YW (Lu, Yuwu); Yuan, C (Yuan, Chun); Zhu, WW (Zhu, Wenwu); Li, XL (Li, Xuelong)

Source: IEEE TRANSACTIONS ON IMAGE PROCESSING  Volume: 27  Issue: 11  Pages: 5248-5260  DOI: 10.1109/TIP.2018.2855433  Published: NOV 2018  

Abstract: As a popular dimensionality reduction method, nonnegative matrix factorization (NMF) has been widely used in image classification. However, the NMF does not consider discriminant information from the data themselves. In addition, most NMF-based methods use the Euclidean distance as a metric, which is sensitive to noise or outliers in data. To solve these problems, in this paper, we introduce structural incoherence and low-rank to NMF and propose a novel nonnegative factorization method, called structurally incoherent low-rank NMF (SILR-NMF), in which we jointly consider structural incoherence and low-rank properties of data for image classification. For the corrupted data, we use the L-1 norm as a constraint to ensure the noise is sparse. SILR-NMF learns a clean data matrix from the noisy data by low-rank learning. As a result, the SILR-NMF can capture the global structure information of the data, which is more robust than local information to noise. By introducing the structural incoherence of the learned clean data, SILR-NMF ensures the clean data points from different classes are as independent as possible. To verify the performance of the proposed method, extensive experiments are conducted on six image databases. The experimental results demonstrate that our proposed method has substantial gain over existing NMF approaches.

Accession Number: WOS:000440203500004

PubMed ID: 30010572

Author Identifiers:

ISSN: 1057-7149

eISSN: 1941-0042

Record 42 of 319

Title: Carboxyl graphene oxide solution saturable absorber for femtosecond mode-locked erbium-doped fiber laser

Author(s): Lv, RD (Lv, Rui-dong); Li, L (Li, Lu); Wang, YG (Wang, Yong-gang); Chen, ZD (Chen, Zhen-dong); Liu, SC (Liu, Si-cong); wang, X (wang, Xi); wang, J (wang, Jiang); Li, YF (Li, Yong-fang)

Source: CHINESE PHYSICS B  Volume: 27  Issue: 11  Article Number: 114214  DOI: 10.1088/1674-1056/27/11/114214  Published: NOV 2018  

Abstract: The carboxyl-functionalized graphene oxide (GO-COOH) is a kind of unique two-dimensional (2D) material and possesses excellent nonlinear saturable absorption property and high water-solubility. In this paper, we prepare saturable absorber (SA) device by depositing GO-COOH nanosheets aqueous solution on a D-shaped fiber. The modulation depth (MD) and saturable intensity of the SA are measured to be 9.6% and 19 MW/cm(2), respectively. By inserting the SA into the erbium-doped fiber (EDF) laser, a passively mode-locked EDF laser has been achieved with the spectrum center wavelength of 1562.76 nm. The pulse duration, repetition rate, and the signal-to-noise ratio (SNR) are 500 fs, 14.79 MHz, and 80 dB, respectively. The maximum average output power is measured to be 3.85 mW. These results indicate that the GO-COOH nanosheets SA can be used as a promising mode locker for the generation of ultrashort pulses.

Accession Number: WOS:000450989100014

Author Identifiers:

ISSN: 1674-1056

eISSN: 1741-4199

Record 43 of 319

Title: Flexible double-cladding ytterbium fibre based 9 W mode-locked laser with 102 fs compressible pulse duration

Author(s): Lv, ZG (Lv, Zhiguo); Yang, Z (Yang, Zhi); Yang, XJ (Yang, Xiaojun); Li, F (Li, Feng); Li, QL (Li, Qianglong); Wan, YS (Wan, Yishan); Zhao, W (Zhao, Wei); Wei, YF (Wei, Yufeng)

Source: LASER PHYSICS LETTERS  Volume: 15  Issue: 11  Article Number: 115109  DOI: 10.1088/1612-202X/aad945  Published: NOV 2018  

Abstract: We report on a high power mode-locked femtosecond fiber laser oscillator with flexible double-cladding (DC) ytterbium-doped fiber (Yb-fiber) as gain medium and a fused fiber combiner as a pump coupling scheme, based on the nonlinear polarization evolution effect in a ring cavity configuration with a dual-stage birefringent plate as the spectral filter. Laser pulses with a pulse energy as high as 122 nJ and compressible pulse duration as short as 102 fs at 1041 mn center wavelength could been obtained. The experimentally recorded power fluctuations were better than 0.42% RMS and 0.40% RMS in 3 h under 5 W and 9 W output power, respectively. The measured beam quality factors M-2 were 1.3 in both the horizontal and perpendicular directions. To the best of our knowledge, this is the highest output power generated from a flexible DC Yb-fiber-based ultrashort pulse mode-locking fiber laser oscillator pumped with a fusion spliced combiner.

Accession Number: WOS:000448146900001

Author Identifiers:

ISSN: 1612-2011

eISSN: 1612-202X