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Sample records for mode psfs based

  1. Correlation Relationship of Performance Shaping Factors (PSFs) for Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bheka, M. Khumalo; Kim, Jonghyun [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    At TMI-2, operators permitted thousands of gallons of water to escape from the reactor plant before realizing that the coolant pumps were behaving abnormally. The coolant pumps were then turned off, which in turn led to the destruction of the reactor itself as cooling was completely lost within the core. Human also plays a role in many aspects of complex systems e.g. in design and manufacture of hardware, interface between human and system and also in maintaining such systems as well as for coping with unusual events that place the NPP system at a risk. This is why human reliability analysis (HRA) - an aspect of risk assessments which systematically identifies and analyzes the causes and consequences of human decisions and actions - is important in nuclear power plant operations. It either upgrades or degrades human performance; therefore it has an impact on the possibility of error. These PSFs can be used in various HRA methods to estimate Human Error Probabilities (HEPs). There are many current HRA methods who propose sets of PSFs for normal operation mode of NPP. Some of these PSFs in the sets have some degree of dependency and overlap. Overlapping PSFs introduce error in HEP evaluations due to the fact that some elements are counted more than once in data; this skews the relationship amongst PSF and masks the way that the elements interact to affect performance. This study uses a causal model that represents dependencies and relationships amongst PSFs for HEP evaluation during normal NPP operational states. The model is built taking into consideration the dependencies among PSFs and thus eliminating overlap. The use of an interdependent model of PSFs is expected to produce more accurate HEPs compared to other current methods. PSF sets produced in this study can be further used as nodes (variables) and directed arcs (causal influence between nodes) in HEP evaluation methods such as Bayesian belief (BN) networks. This study was done to estimate the relationships

  2. An Update on Simulating Imaging, Spectroscopic, and Coronagraphic PSFs for JWST (and WFIRST too!)

    Science.gov (United States)

    Perrin, Marshall D.; Long, Joseph D.; Zimmerman, Neil T.; Van Gorkom, Kyle

    2016-06-01

    Simulated point spread functions (PSFs) are an essential tool in preparing for future space telescopes, supporting pre-launch science simulations, observation planning, and analysis software development. The open-source Python package WebbPSF provides simulated PSFs for all of JWST's instruments and observing modes. We present the latest updates to WebbPSF based on both updated models ofthe assembled telescope optics and recent cryo-test data for the science instruments. Outputs from this latest version of WebbPSF will support the JWST Exposure Time Calculator and the first calls for proposals in the year ahead, among many other uses by the community. Furthermore, the same toolkit also now provides support for simulating PSFs for both the WFI and CGI instruments planned for WFIRST.

  3. Opportunities and Internationalisation of PSFs

    DEFF Research Database (Denmark)

    Jensen, Søren Henning; Poulfelt, Flemming

    2017-01-01

    The article focuses on the relationship between internationalisation and opportunities of firms within the professional services industry. The key question explored is whether internationalisation of PSFs is a passive strategy driven by clients' internationalisation or if it is a deliberate searc...

  4. Constraint matrix factorization for space variant PSFs fiel restoration

    CERN Document Server

    Mboula, F M Ngolè; Okumura, K; Amiaux, J; Hudelot, P

    2016-01-01

    Context: in large-scale spatial surveys, the Point Spread Function (PSF) varies across the instrument ?eld of view (FOV). Local measurements of the PSFs are given by the isolated stars images. Yet, these estimates may not be directly usable for post-processings because of the observational noise and potentially the aliasing. Aims: given a set of aliased and noisy stars images from a telescope, we want to estimate well-resolved and noise-free PSFs at the observed stars positions, in particular, exploiting the spatial correlation of the PSFs across the FOV. Contributions: we introduce RCA (Resolved Components Analysis) which is a noise-robust dimension reduction and super-resolution method based on matrix- factorization. We propose an original way of using the PSFs spatial correlation in the restoration process through sparsity. The introduced formalism can be applied to correlated data sets with respect to any euclidean parametric space. Results: we tested our method on simulated monochromatic PSFs of Euclid t...

  5. The Impact of Interpixel Capacitance on WFIRST PSFs

    CERN Document Server

    Kannawadi, Arun; Mandelbaum, Rachel; Hirata, Christopher M; Kruk, Jeffrey W; Rhodes, Jason D

    2015-01-01

    Unlike optical CCDs, near-infrared detectors, which are based on CMOS hybrid readout technology, typically suffer from electrical crosstalk between the pixels. The interpixel capacitance (IPC) responsible for the crosstalk affects the point-spread function (PSF) of the telescope, increasing the size and modifying the shape of all objects in the images while correlating the Poisson noise. Upcoming weak lensing surveys that use these detectors, such as WFIRST, place stringent requirements on the PSF size and shape (and the level at which these are known), which in turn must be translated into requirements on IPC. To facilitate this process, we present a first study of the effect of IPC on WFIRST PSF sizes and shapes. Realistic PSFs are forward-simulated from physical principles for each WFIRST bandpass. We explore how the PSF size and shape depends on the range of IPC coupling with pixels that are connected along an edge or corner; for the expected level of IPC in WFIRST, IPC increases the PSF sizes by $\\sim$5\\...

  6. Gemini Planet Imager Observational Calibrations III: Empirical Measurement Methods and Applications of High-Resolution Microlens PSFs

    OpenAIRE

    Ingraham, Patrick; Ruffio, Jean-Baptiste; Perrin, Marshall D.; Wolff, Schuyler G.; Draper, Zachary H.; Maire, Jerome; Marchis, Franck; Fesquet, Vincent

    2014-01-01

    The newly commissioned Gemini Planet Imager (GPI) combines extreme adaptive optics, an advanced coronagraph, precision wavefront control and a lenslet-based integral field spectrograph (IFS) to measure the spectra of young extrasolar giant planets between 0.9-2.5 um. Each GPI detector image, when in spectral model, consists of ~37,000 microspectra which are under or critically sampled in the spatial direction. This paper demonstrates how to obtain high-resolution microlens PSFs and discusses ...

  7. Study on Performance Shaping Factors (PSFs) Quantification Method in Human Reliability Analysis (HRA)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ar Ryum; Jang, Inseok Jang; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of); Park, Jinkyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jong Hyun [KEPCO, Ulsan (Korea, Republic of)

    2015-05-15

    The purpose of HRA implementation is 1) to achieve the human factor engineering (HFE) design goal of providing operator interfaces that will minimize personnel errors and 2) to conduct an integrated activity to support probabilistic risk assessment (PRA). For these purposes, various HRA methods have been developed such as technique for human error rate prediction (THERP), simplified plant analysis risk human reliability assessment (SPAR-H), cognitive reliability and error analysis method (CREAM) and so on. In performing HRA, such conditions that influence human performances have been represented via several context factors called performance shaping factors (PSFs). PSFs are aspects of the human's individual characteristics, environment, organization, or task that specifically decrements or improves human performance, thus respectively increasing or decreasing the likelihood of human errors. Most HRA methods evaluate the weightings of PSFs by expert judgment and explicit guidance for evaluating the weighting is not provided. It has been widely known that the performance of the human operator is one of the critical factors to determine the safe operation of NPPs. HRA methods have been developed to identify the possibility and mechanism of human errors. In performing HRA methods, the effect of PSFs which may increase or decrease human error should be investigated. However, the effect of PSFs were estimated by expert judgment so far. Accordingly, in order to estimate the effect of PSFs objectively, the quantitative framework to estimate PSFs by using PSF profiles is introduced in this paper.

  8. Professional identities at stake in strategic change - on the formation of professional selves in changing PSFs

    OpenAIRE

    2009-01-01

    Professional Service Firms (PSFs) are increasingly pressured to strategic changes by evolutions in their environments. Research has especially emphasized changing client behaviours and demands, globalization and increasing competition. However, the internal dynamics of strategic change in PSFs remain under-investigated. The current paper focuses specifically on the role of professional identities in processes of strategic change, as identity has emerged as a key variable for understanding PSF...

  9. The M 4 Core Project with HST - V. Characterizing the PSFs of WFC3/UVIS by focus★

    Science.gov (United States)

    Anderson, J.; Bedin, L. R.

    2017-09-01

    As part of the astrometric Hubble Space Telescope (HST) large program GO-12911, we conduct an in-depth study to characterize the point spread function (PSF) of the Uv-VISual channel of the Wide Field Camera 3 (WFC3), as a necessary step to achieve the astrometric goals of the program. We extracted a PSF from each of the 589 deep exposures taken through the F467M filter over the course of a year and find that the vast majority of the PSFs lie along a 1-D locus that stretches continuously from one side of focus, through optimal focus, to the other side of focus. We constructed a focus-diverse set of PSFs and find that with only five medium-bright stars in an exposure it is possible to pin down the focus level of that exposure. We show that the focus-optimized PSF does a considerably better job fitting stars than the average 'library' PSF, especially when the PSF is out of focus. The fluxes and positions are significantly improved over the 'library' PSF treatment. These results are beneficial for a much broader range of scientific applications than simply the program at hand, but the immediate use of these PSFs will enable us to search for astrometric wobble in the bright stars in the core of the globular cluster M 4, which would indicate a dark, high-mass companion, such as a white dwarf, neutron star or black hole.

  10. An Eavesdropping Detecting Approach Based on Mode-Mode Correlation

    Institute of Scientific and Technical Information of China (English)

    XIONG Jin; ZENG Gui-Hua; ZHOU Nan-Run

    2005-01-01

    @@ We find that second-order coherence as well as a Hanbury-Brown-Twiss intensity interferometer may provide an optimal approach for eavesdropping detection in the quantum key distribution based on two-mode squeezed'vacuum states. With this approach, eavesdropping can be easily detected without sacrificing extra secret bits as the test key. In addition, the efficiency of the quantum key distribution protocol is enhanced greatly.

  11. PLC-based mode multi/demultiplexers for mode division multiplexing

    Science.gov (United States)

    Saitoh, Kunimasa; Hanzawa, Nobutomo; Sakamoto, Taiji; Fujisawa, Takeshi; Yamashita, Yoko; Matsui, Takashi; Tsujikawa, Kyozo; Nakajima, Kazuhide

    2017-02-01

    Recently developed PLC-based mode multi/demultiplexers (MUX/DEMUXs) for mode division multiplexing (MDM) transmission are reviewed. We firstly show the operation principle and basic characteristics of PLC-based MUX/DEMUXs with an asymmetric directional coupler (ADC). We then demonstrate the 3-mode (2LP-mode) multiplexing of the LP01, LP11a, and LP11b modes by using fabricated PLC-based mode MUX/DEMUX on one chip. In order to excite LP11b mode in the same plane, a PLC-based LP11 mode rotator is introduced. Finally, we show the PLC-based 6-mode (4LP-mode) MUX/DEMUX with a uniform height by using ADCs, LP11 mode rotators, and tapered waveguides. It is shown that the LP21a mode can be excited from the LP11b mode by using ADC, and the two nearly degenerated LP21b and LP02 modes can be (de)multiplexed separately by using tapered mode converter from E13 (E31) mode to LP21b (LP02) mode.

  12. Human Error Probabilites (HEPs) for generic tasks and Performance Shaping Factors (PSFs) selected for railway operations

    DEFF Research Database (Denmark)

    Thommesen, Jacob; Andersen, Henning Boje

    at task level, which can be performed with fewer resources than a more detailed analysis of specific errors for each task. The generic tasks are presented with estimated Human Error Probabili-ties (HEPs) based on and extrapolated from the HRA literature, and estimates are compared with samples of measures...... on estimates derived from industries other than rail and the general warning that a task-based analysis is less precise than an error-based one. The authors recommend that estimates be adjusted to actual measures of task failures when feasible....... collaboration with Banedanmark. The estimates provided are based on HRA literature and primarily the HEART method, being recently been adapted for railway tasks by the British Rail Safety and Stan-dards Board (RSSB). The method presented in this report differs from the RSSB tool by supporting an analysis...

  13. Seismic base isolation by nonlinear mode localization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [University of Illinois, Department of Civil and Environmental Engineering, Urbana, IL (United States); Washington University, Department of Civil and Environmental Engineering, St. Louis, MO (United States); McFarland, D.M. [University of Illinois, Department of Aerospace Engineering, Urbana, IL (United States); Vakakis, A.F. [National Technical University of Athens, Division of Mechanics (Greece); Bergman, L.A. [University of Illinois, Department of Mechanical and Industrial Engineering, Urbana, IL (United States)

    2005-03-01

    In this paper, the performance of a nonlinear base-isolation system, comprised of a nonlinearly sprung subfoundation tuned in a 1:1 internal resonance to a flexible mode of the linear primary structure to be isolated, is examined. The application of nonlinear localization to seismic isolation distinguishes this study from other base-isolation studies in the literature. Under the condition of third-order smooth stiffness nonlinearity, it is shown that a localized nonlinear normal mode (NNM) is induced in the system, which confines energy to the subfoundation and away from the primary or main structure. This is followed by a numerical analysis wherein the smooth nonlinearity is replaced by clearance nonlinearity, and the system is excited by ground motions representing near-field seismic events. The performance of the nonlinear system is compared with that of the corresponding linear system through simulation, and the sensitivity of the isolation system to several design parameters is analyzed. These simulations confirm the existence of the localized NNM, and show that the introduction of simple clearance nonlinearity significantly reduces the seismic energy transmitted to the main structure, resulting in significant attenuation in the response. (orig.)

  14. Aptasensors Based on Whispering Gallery Mode Resonators

    Science.gov (United States)

    Nunzi Conti, Gualtiero; Berneschi, Simome; Soria, Silvia

    2016-01-01

    In this paper, we review the literature on optical evanescent field sensing in resonant cavities where aptamers are used as biochemical receptors. The combined advantages of highly sensitive whispering gallery mode resonator (WGMR)-based transducers, and of the unique properties of aptamers make this approach extremely interesting in the medical field, where there is a particularly high need for devices able to provide real time diagnosis for cancer, infectious diseases, or strokes. However, despite the superior performances of aptamers compared to antibodies and WGMR to other evanescent sensors, there is not much literature combining both types of receptors and transducers. Up to now, the WGMR that have been used are silica microspheres and silicon oxynitride (SiON) ring resonators. PMID:27438861

  15. Aptasensors Based on Whispering Gallery Mode Resonators

    Directory of Open Access Journals (Sweden)

    Gualtiero Nunzi Conti

    2016-07-01

    Full Text Available In this paper, we review the literature on optical evanescent field sensing in resonant cavities where aptamers are used as biochemical receptors. The combined advantages of highly sensitive whispering gallery mode resonator (WGMR-based transducers, and of the unique properties of aptamers make this approach extremely interesting in the medical field, where there is a particularly high need for devices able to provide real time diagnosis for cancer, infectious diseases, or strokes. However, despite the superior performances of aptamers compared to antibodies and WGMR to other evanescent sensors, there is not much literature combining both types of receptors and transducers. Up to now, the WGMR that have been used are silica microspheres and silicon oxynitride (SiON ring resonators.

  16. Multiwavelength mode-locked cylindrical vector beam fiber laser based on mode selective coupler

    Science.gov (United States)

    Huang, Ping; Cai, Yu; Wang, Jie; Wan, Hongdan; Zhang, Zuxing; Zhang, Lin

    2017-10-01

    We propose and demonstrate a multiwavelength mode-locked fiber laser with cylindrical vector beam generation for the first time, to the best of our knowledge. The mode-locking mechanism is based on a nonlinear polarization rotation effect in fiber, and the multiwavelength operation is contributed to by an in-line birefringence fiber filter with periodic multiple passbands, formed by incorporating a section of polarization maintaining fiber into the laser cavity with a fiber polarizer. Furthermore, by using a home-made mode selective coupler, which acts as both a mode converter from fundamental mode to higher-order mode and an output coupler, multiwavelength mode-locked cylindrical vector beams have been obtained. This may have potential applications in mode-division multiplexing optical fiber communication and material processing.

  17. Few mode fibers based quasi-single mode Raman distributed temperature sensor

    Science.gov (United States)

    Wu, Hao; Wang, Meng; Liu, Tongqing; Yang, Chen; Tong, Weijun; Fu, Songnian; Tang, Ming

    2017-04-01

    We demonstrate a distributed temperature sensor based on quasi-single mode (QSM) Raman scattering in few mode fibers (FMFs). The FMF allows much larger input pump power before the initiate of stimulated Raman scattering compared with the standard single mode fiber (SSMF) and mitigates the detrimental differential mode group delay (DMGD) existing in the conventional multimode fiber (MMF) based Raman distributed temperature sensor (RDTS). Distributed temperature sensing is realized using conventional RDTS hardware over 20km FMFs within 90s, with a spatial resolution of 3m. The temperature resolution is 2.3°C @10km and 6.7°C @20km, respectively.

  18. Optical mode switch based on multimode interference couplers

    Science.gov (United States)

    Xiao, Huifu; Deng, Lin; Zhao, Guolin; Liu, Zilong; Meng, Yinghao; Guo, Xiaonan; Liu, Guipeng; Liu, Su; Ding, Jianfeng; Tian, Yonghui

    2017-02-01

    In this paper, we propose an optical mode switch based on two cascaded multimode interference (MMI) couplers. After a fundamental mode divided into two equal-power fundamental modes in the first MMI coupler, the thermo-optic effect is employed to modulate the phase of the two fundamental modes before directed to the next MMI for the purpose of mode switching. By adjusting the electric signals applied to the modulation arms, the proposed device can implement mode switching in three states: (a) one first-order and two fundamental modes simultaneously output, (b) one first-order mode output, and (c) two fundamental modes output. As a result, the simulated excess losses are -0.29 dB, -0.10 dB, and -0.63 dB, respectively.

  19. Higher-order mode photonic crystal based nanofluidic sensor

    Science.gov (United States)

    Peng, Wang; Chen, Youping; Ai, Wu

    2017-01-01

    A higher-order photonic crystal (PC) based nanofluidic sensor, which worked at 532 nm, was designed and demonstrated. A systematical and detailed method for sculpturing a PC sensor for a given peak wavelength value (PWV) and specified materials was illuminated. It was the first time that the higher order mode was used to design PC based nanofluidic sensor, and the refractive index (RI) sensitivity of this sensor had been verified with FDTD simulation software from Lumerical. The enhanced electrical field of higher order mode structure was mostly confined in the channel area, where the enhance field is wholly interacting with the analytes in the channels. The comparison of RI sensitivity between fundamental mode and higher order mode shows the RI variation of higher order mode is 124.5 nm/RIU which is much larger than the fundamental mode. The proposed PC based nanofluidic structure pioneering a novel style for future optofluidic design.

  20. Multi-mode sliding mode control for precision linear stage based on fixed or floating stator.

    Science.gov (United States)

    Fang, Jiwen; Long, Zhili; Wang, Michael Yu; Zhang, Lufan; Dai, Xufei

    2016-02-01

    This paper presents the control performance of a linear motion stage driven by Voice Coil Motor (VCM). Unlike the conventional VCM, the stator of this VCM is regulated, which means it can be adjusted as a floating-stator or fixed-stator. A Multi-Mode Sliding Mode Control (MMSMC), including a conventional Sliding Mode Control (SMC) and an Integral Sliding Mode Control (ISMC), is designed to control the linear motion stage. The control is switched between SMC and IMSC based on the error threshold. To eliminate the chattering, a smooth function is adopted instead of a signum function. The experimental results with the floating stator show that the positioning accuracy and tracking performance of the linear motion stage are improved with the MMSMC approach.

  1. Oscillating Guided Modes in Graphene-Based Asymmetric Waveguides

    Institute of Scientific and Technical Information of China (English)

    PENG Ping; ZHANG Peng; LIU Jian-Ke; CAO Zhen-Zhou; LI Guan-Qiang

    2012-01-01

    We investigate the guided modes in monolayer graphene-based waveguides with asymmetric quantum well structure induced by unequal dc voltages. The dispersion relation for the guided modes is obtained analytically, the structures of the guided modes are discussed under three distinct cases. For the cases of the classical motion and the Klein tunneling, the asymmetric structure does not influence the mode structures dramatically compared with that in the symmetric waveguide. But for the mixing case of the former two, the mode structures and the motion characteristics for the electron and the hole exhibit different behaviors at same condition. The results may be helpful for the practical application of graphene-based quantum devices.

  2. Ohmic scaling based on current diffusive ballooning mode

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masatoshi; Itoh, Sanae [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Fukuyama, Atsushi; Itoh, Kimitaka

    1996-01-01

    Based on the anomalous transport model due to current diffusive ballooning mode turbulence, the global energy confinement time in a tokamak with Ohmic heating is theoretically studied. Relations to empirical scaling laws are also discussed. (author)

  3. Technology Innovation Mode of Agricultural Leading Enterprise——Based on the Virtual Organization Mode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the definition of technology innovation of agricultural leading enterprises by domestic and foreign experts and scholars,technology innovation of agricultural enterprises is a process of new market increment,which uses new knowledge,technology,process and production mode,produces new products,offers new services and realizes commercialization. Characteristics of agricultural technology innovation are introduced,such as obvious regionality,relatively high risk,long-term periodicity and public attribute. Predicament for technology innovation of leading enterprises is analyzed,such as technical constraints,financial constraints and personnel constraints. Technological Innovation Mode can be classified into three modes of independent innovation,imitative innovation and cooperative innovation by the method of technology innovation. Among them,since there are some defects in the technology innovation process,independent innovation and imitative innovation are generally not used for the innovation of agricultural enterprises. Cooperative Innovation Mode can rely on foreign aid,can realize complementary advantages and achievement sharing,and can be widely applied in the agricultural innovation enterprise. Virtual organization in cooperation innovation mode is described,which makes up for technology,capital and human resources barriers in the process of agricultural enterprise innovation. Therefore,this mode is popular among the agricultural innovation enterprise.

  4. Multi-mode reliability-based design of horizontal curves.

    Science.gov (United States)

    Essa, Mohamed; Sayed, Tarek; Hussein, Mohamed

    2016-08-01

    Recently, reliability analysis has been advocated as an effective approach to account for uncertainty in the geometric design process and to evaluate the risk associated with a particular design. In this approach, a risk measure (e.g. probability of noncompliance) is calculated to represent the probability that a specific design would not meet standard requirements. The majority of previous applications of reliability analysis in geometric design focused on evaluating the probability of noncompliance for only one mode of noncompliance such as insufficient sight distance. However, in many design situations, more than one mode of noncompliance may be present (e.g. insufficient sight distance and vehicle skidding at horizontal curves). In these situations, utilizing a multi-mode reliability approach that considers more than one failure (noncompliance) mode is required. The main objective of this paper is to demonstrate the application of multi-mode (system) reliability analysis to the design of horizontal curves. The process is demonstrated by a case study of Sea-to-Sky Highway located between Vancouver and Whistler, in southern British Columbia, Canada. Two noncompliance modes were considered: insufficient sight distance and vehicle skidding. The results show the importance of accounting for several noncompliance modes in the reliability model. The system reliability concept could be used in future studies to calibrate the design of various design elements in order to achieve consistent safety levels based on all possible modes of noncompliance.

  5. MULTI-BLOCK CHAINING-BASED AUTHENTICATION MODE

    Institute of Scientific and Technical Information of China (English)

    Huang Yuhua; Hu Aiqun; Zhong Ziguo

    2006-01-01

    A fast authentication mode based on Multi-Block Chaining (MBC) is put forward; and its security is proved. The MBC mode is for new generation block cipher algorithms. Its speed is about 13% faster than that of the authentication modes in common use (for example, cipher block chaining-message authentication code mode). The dependence test results meet the requirement. The MBC mode is complete; its degree of avalanche effect is about 0.9993; its degree of strict avalanche criterion is 0.992 or so. The frequency test results indicate that the output generated by the MBC mode has uniformity. The binary matrix rank test results imply that it is linear independent among disjoint sub-matrices of the output. Maurer's universal statistical test results show that the output could be significantly compressed without loss of information. Run test, spectral test,non-overlapping template matching test, overlapping template matching test, Lempel-Ziv compression test,linear complexity test, serial test, approximate entropy test, cumulative sums test, random excursions test and random excursions variant test results fulfill the requirements of all. Therefore the MBC mode has good pseudo-randomness. Thus the security of MBC mode is verified by the way of statistical evaluation.

  6. Intensity based sensor based on single mode optical fiber patchcords

    Science.gov (United States)

    Bayuwati, Dwi; Waluyo, Tomi Budi; Mulyanto, Imam

    2016-11-01

    This paper describes the use of several single mode (SM) fiber patchcords available commercially in the market for intensity based sensor by taking the benefit of bending loss phenomenon. Firtsly, the full transmission spectrum of all fiber patchcords were measured and analyzed to examine its bending properties at a series of wavelength using white light source and optical spectrum analyzer. Bending spectral at various bending diameter using single wavelength light sources were then measured for demonstration.Three good candidates for the intensity based sensor are SM600 fiber patchcord with 970 nm LED, SMF28 fiber patchcord with 1050 nm LED and 780HP fiber patchcord with 1310 nm LED which have noticeable bending sensitive area. Experiments show that the combination of the SMF28with 1050 nm LED has 30 mm measurement range which is the widest; with sensitivity 0.107 dB/mm and resolution 0.5 mm compared with combination of SM600 patchcord and LED 970 nm which has the best sensitivity (0.891 dB/mm) and resolution (0.06 mm) but smaller range measurement (10 mm). Some suitable applications for each fiber patchcord - light source pair have also been discussed.

  7. Alcohol sensor based on single-mode-multimode-single-mode fiber structure

    Science.gov (United States)

    Mefina Yulias, R.; Hatta, A. M.; Sekartedjo, Sekartedjo

    2016-11-01

    Alcohol sensor based on Single-mode -Multimode-Single-mode (SMS) fiber structure is being proposed to sense alcohol concentration in alcohol-water mixtures. This proposed sensor uses refractive index sensing as its sensing principle. Fabricated SMS fiber structure had 40 m of multimode length. With power input -6 dBm and wavelength 1550 nm, the proposed sensor showed good response with sensitivity 1,983 dB per % v/v with measurement range 05 % v/v and measurement span 0,5% v/v.

  8. A new mixed-mode filter based on MDDCCs

    Science.gov (United States)

    Wang, Lixue; Wang, Chunyue; Zhang, Junru; Liang, Xiao; Jiang, Shuangshuang

    2015-12-01

    A new mixed mode filter based on MDDCC (Modify Differential Difference Current Conveyor) is proposed, the structure of filter is simple, the circuit consist of only three active MDDCCs, five resistors and three grounded capacitors. The filter can realize the filter of current mode and voltage mode, which can realize the function of low pass biquad, band pass biquad and high pass biquad simultaneously. The computer simulation of PSPICE uses 0.18μm TSMC CMOS and the theoretical results are validated the proposed circuit.

  9. OFCC based voltage and transadmittance mode instrumentation amplifier

    Science.gov (United States)

    Nand, Deva; Pandey, Neeta; Pandey, Rajeshwari; Tripathi, Prateek; Gola, Prashant

    2017-07-01

    The operational floating current conveyor (OFCC) is a versatile active block due to the availability of both low and high input and output impedance terminals. This paper addresses the realization of OFCC based voltage and transadmittance mode instrumentation amplifiers (VMIA and TAM IA). It employs three OFCCs and seven resistors. The transadmittance mode operation can easily be obtained by simply connecting an OFCC based voltage to current converter at the output. The effect of non-idealities of OFCC, in particular finite transimpedance and tracking error, on system performance is also dealt with and corresponding mathematical expressions are derived. The functional verification is performed through SPICE simulation using CMOS based implementation of OFCC.

  10. H.264 SVC Complexity Reduction Based on Likelihood Mode Decision

    Directory of Open Access Journals (Sweden)

    L. Balaji

    2015-01-01

    Full Text Available H.264 Advanced Video Coding (AVC was prolonged to Scalable Video Coding (SVC. SVC executes in different electronics gadgets such as personal computer, HDTV, SDTV, IPTV, and full-HDTV in which user demands various scaling of the same content. The various scaling is resolution, frame rate, quality, heterogeneous networks, bandwidth, and so forth. Scaling consumes more encoding time and computational complexity during mode selection. In this paper, to reduce encoding time and computational complexity, a fast mode decision algorithm based on likelihood mode decision (LMD is proposed. LMD is evaluated in both temporal and spatial scaling. From the results, we conclude that LMD performs well, when compared to the previous fast mode decision algorithms. The comparison parameters are time, PSNR, and bit rate. LMD achieve time saving of 66.65% with 0.05% detriment in PSNR and 0.17% increment in bit rate compared with the full search method.

  11. Resonant mode for gravitational wave detectors based on atom interferometry

    Science.gov (United States)

    Graham, Peter W.; Hogan, Jason M.; Kasevich, Mark A.; Rajendran, Surjeet

    2016-11-01

    We describe an atom interferometric gravitational wave detector design that can operate in a resonant mode for increased sensitivity. By oscillating the positions of the atomic wave packets, this resonant detection mode allows for coherently enhanced, narrow-band sensitivity at target frequencies. The proposed detector is flexible and can be rapidly switched between broadband and narrow-band detection modes. For instance, a binary discovered in broadband mode can subsequently be studied further as the inspiral evolves by using a tailored narrow-band detector response. In addition to functioning like a lock-in amplifier for astrophysical events, the enhanced sensitivity of the resonant approach also opens up the possibility of searching for important cosmological signals, including the stochastic gravitational wave background produced by inflation. We give an example of detector parameters which would allow detection of inflationary gravitational waves down to ΩGW˜10-14 for a two-satellite space-based detector.

  12. Railway Wheel Flat Detection Based on Improved Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Yifan Li

    2016-01-01

    Full Text Available This study explores the capacity of the improved empirical mode decomposition (EMD in railway wheel flat detection. Aiming at the mode mixing problem of EMD, an EMD energy conservation theory and an intrinsic mode function (IMF superposition theory are presented and derived, respectively. Based on the above two theories, an improved EMD method is further proposed. The advantage of the improved EMD is evaluated by a simulated vibration signal. Then this method is applied to study the axle box vibration response caused by wheel flats, considering the influence of both track irregularity and vehicle running speed on diagnosis results. Finally, the effectiveness of the proposed method is verified by a test rig experiment. Research results demonstrate that the improved EMD can inhibit mode mixing phenomenon and extract the wheel fault characteristic effectively.

  13. Tensor product model transformation based decoupled terminal sliding mode control

    Science.gov (United States)

    Zhao, Guoliang; Li, Hongxing; Song, Zhankui

    2016-06-01

    The main objective of this paper is to propose a tensor product model transformation based decoupled terminal sliding mode controller design methodology. The methodology is divided into two steps. In the first step, tensor product model transformation is applied to the single-input-multi-output system and a parameter-varying weighted linear time-invariant system is obtained. Then, decoupled terminal sliding mode controller is designed based on the linear time-invariant systems. The main novelty of this paper is that the nonsingular terminal sliding mode control design is based on a numerical model rather than an analytical one. Finally, simulations are tested on cart-pole system and translational oscillations with a rotational actuator system.

  14. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2014-02-01

    Full Text Available This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that the light transmission through etched fiber at 1550 nm wavelength optical source becomes highly temperature sensitive, compared to the temperature insensitive behavior observed in un-etched fiber for the range on 30ºC to 100ºC at 1550 nm. The sensor response under temperature cycling is repeatable and, proposed to be useful for low frequency analogue signal transmission over optical fiber by means of inline thermal modulation approach.

  15. Porphyrin-based sensor nanoarchitectonics in diverse physical detection modes.

    Science.gov (United States)

    Ishihara, Shinsuke; Labuta, Jan; Van Rossom, Wim; Ishikawa, Daisuke; Minami, Kosuke; Hill, Jonathan P; Ariga, Katsuhiko

    2014-06-07

    Porphyrins and related families of molecules are important organic modules as has been reflected in the award of the Nobel Prizes in Chemistry in 1915, 1930, 1961, 1962, 1965, and 1988 for work on porphyrin-related biological functionalities. The porphyrin core can be synthetically modified by introduction of various functional groups and other elements, allowing creation of numerous types of porphyrin derivatives. This feature makes porphyrins extremely useful molecules especially in combination with their other interesting photonic, electronic and magnetic properties, which in turn is reflected in their diverse signal input-output functionalities based on interactions with other molecules and external stimuli. Therefore, porphyrins and related macrocycles play a preeminent role in sensing applications involving chromophores. In this review, we discuss recent developments in porphyrin-based sensing applications in conjunction with the new advanced concept of nanoarchitectonics, which creates functional nanostructures based on a profound understanding of mutual interactions between the individual nanostructures and their arbitrary arrangements. Following a brief explanation of the basics of porphyrin chemistry and physics, recent examples in the corresponding fields are discussed according to a classification based on physical modes of detection including optical detection (absorption/photoluminescence spectroscopy and energy and electron transfer processes), other spectral modes (circular dichroism, plasmon and nuclear magnetic resonance), electronic and electrochemical modes, and other sensing modes.

  16. Adaptive robust controller based on integral sliding mode concept

    Science.gov (United States)

    Taleb, M.; Plestan, F.

    2016-09-01

    This paper proposes, for a class of uncertain nonlinear systems, an adaptive controller based on adaptive second-order sliding mode control and integral sliding mode control concepts. The adaptation strategy solves the problem of gain tuning and has the advantage of chattering reduction. Moreover, limited information about perturbation and uncertainties has to be known. The control is composed of two parts: an adaptive one whose objective is to reject the perturbation and system uncertainties, whereas the second one is chosen such as the nominal part of the system is stabilised in zero. To illustrate the effectiveness of the proposed approach, an application on an academic example is shown with simulation results.

  17. DOCCⅡ-based electronically tunable current-mode biquadratic filters

    Institute of Scientific and Technical Information of China (English)

    Wang Weidong

    2005-01-01

    A complete state variable current-mode biquadratic filter built by duo-output CCⅡ (DOCCⅡ) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCⅡ. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.

  18. Robust observer-based adaptive fuzzy sliding mode controller

    Science.gov (United States)

    Oveisi, Atta; Nestorović, Tamara

    2016-08-01

    In this paper, a new observer-based adaptive fuzzy integral sliding mode controller is proposed based on the Lyapunov stability theorem. The plant is subjected to a square-integrable disturbance and is assumed to have mismatch uncertainties both in state- and input-matrices. Based on the classical sliding mode controller, the equivalent control effort is obtained to satisfy the sufficient requirement of sliding mode controller and then the control law is modified to guarantee the reachability of the system trajectory to the sliding manifold. In order to relax the norm-bounded constrains on the control law and solve the chattering problem of sliding mode controller, a fuzzy logic inference mechanism is combined with the controller. An adaptive law is then introduced to tune the parameters of the fuzzy system on-line. Finally, for evaluating the controller and the robust performance of the closed-loop system, the proposed regulator is implemented on a real-time mechanical vibrating system.

  19. GEOTECNOLOGIA COMO SUPORTE PARA GERÊNCIA DE PSFs: UM ESTUDO DE CASO PARA O MUNICÍPIO DE VIÇOSA – MG

    Directory of Open Access Journals (Sweden)

    Taciano Oliveira da Silva

    2010-08-01

    Full Text Available Neste artigo abordou-se a aplicação da geotecnologia na área de saúde pública, a partir da elaboração de um banco de dados sobre as ocorrências de diarréias, dengue, diabetes e hipertensão, no município de Viçosa – MG. Os dados foram coletados nos postos de saúde da família (PSFs, no posto de combate a dengues e no setor de vigilância epidemiológica da secretaria municipal de saúde, e são referentes ao ano de 2007, com exceção para as ocorrências de diarréia que constam também os dados do ano de 2006. A geotecnologia, a partir do uso de equipamento GPS e de um sistema de informação geográfica (SIG, forneceu um suporte valioso para a análise e a compreensão do comportamento espacial das doenças analisadas. Este entendimento permitiu verificar os locais mais carentes de assistência de saúde preventiva. A geração de mapas auxiliará os agentes de saúde na localização das áreas de ocorrência dos eventos, otimizando o trabalho preventivo de saúde no município.

  20. Realization of OFCC based Transimpedance Mode Instrumentation Amplifier

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2016-01-01

    Full Text Available The paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three Operational Floating Current Conveyors (OFCCs and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematicThe paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three operational floating current conveyors (OFCCs and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematic.

  1. Detecting mode hopping in single-longitudinal-mode fiber ring lasers based on an unbalanced fiber Michelson interferometer.

    Science.gov (United States)

    Ma, Mingxiang; Hu, Zhengliang; Xu, Pan; Wang, Wei; Hu, Yongming

    2012-10-20

    A method of detecting mode hopping for single-longitudinal-mode (SLM) fiber ring lasers has been proposed and experimentally demonstrated. The method that is based on an unbalanced Michelson interferometer (MI) utilizing phase generated carrier modulation instantly transforms mode-hopping dynamics into steep phase changes of the interferometer. Multiform mode hops in an SLM erbium-doped fiber ring laser with an 18.6 MHz mode spacing have been detected exactly in real-time domain and discussed in detail. Numerical results show that the MI-based method has a high testing sensitivity for identifying mode hopping, which will play a significant role in evaluating the output stability of SLM fiber lasers.

  2. Sliding mode control based guidance law with impact angle constraint

    Institute of Scientific and Technical Information of China (English)

    Zhao Yao; Sheng Yongzhi; Liu Xiangdong

    2014-01-01

    The terminal guidance problem for an unpowered lifting reentry vehicle against a sta-tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a desired impact angle. In this paper, a sliding mode control (SMC)-based guidance law is developed to satisfy the terminal angle constraint. Firstly, a specific sliding mode function is designed, and the terminal requirements can be achieved by enforcing both the sliding mode function and its derivative to zero at the end of the flight. Then, a backstepping approach is used to ensure the finite-time reaching phase of the sliding mode and the analytic expression of the control effort can be obtained. The trajectories generated by this method only depend on the initial and terminal conditions of the terminal phase and the instantaneous states of the vehicle. In order to test the performance of the proposed guidance law in practical application, numerical simulations are carried out by taking all the aerodynamic parameters into consideration. The effec-tiveness of the proposed guidance law is verified by the simulation results in various scenarios.

  3. Batch Mode Active Sampling based on Marginal Probability Distribution Matching.

    Science.gov (United States)

    Chattopadhyay, Rita; Wang, Zheng; Fan, Wei; Davidson, Ian; Panchanathan, Sethuraman; Ye, Jieping

    2012-01-01

    Active Learning is a machine learning and data mining technique that selects the most informative samples for labeling and uses them as training data; it is especially useful when there are large amount of unlabeled data and labeling them is expensive. Recently, batch-mode active learning, where a set of samples are selected concurrently for labeling, based on their collective merit, has attracted a lot of attention. The objective of batch-mode active learning is to select a set of informative samples so that a classifier learned on these samples has good generalization performance on the unlabeled data. Most of the existing batch-mode active learning methodologies try to achieve this by selecting samples based on varied criteria. In this paper we propose a novel criterion which achieves good generalization performance of a classifier by specifically selecting a set of query samples that minimizes the difference in distribution between the labeled and the unlabeled data, after annotation. We explicitly measure this difference based on all candidate subsets of the unlabeled data and select the best subset. The proposed objective is an NP-hard integer programming optimization problem. We provide two optimization techniques to solve this problem. In the first one, the problem is transformed into a convex quadratic programming problem and in the second method the problem is transformed into a linear programming problem. Our empirical studies using publicly available UCI datasets and a biomedical image dataset demonstrate the effectiveness of the proposed approach in comparison with the state-of-the-art batch-mode active learning methods. We also present two extensions of the proposed approach, which incorporate uncertainty of the predicted labels of the unlabeled data and transfer learning in the proposed formulation. Our empirical studies on UCI datasets show that incorporation of uncertainty information improves performance at later iterations while our studies on 20

  4. Spectropolarimetric interferometer based on single-mode glass waveguides.

    Science.gov (United States)

    Qi, Zhi-Mei; Xia, Shanhong; Matsuda, Naoki

    2008-02-04

    A novel simple spectropolarimetric interferometer was developed based on single-mode potassium ion-exchanged (PIE) glass waveguides that generally have a large birefringence due to the compressive stress induced in the ion-exchanged layers. By using the spectropolarimetric interferometry, wavelength dependence of the modal birefringence of single-mode PIE waveguides was accurately obtained in a broad bandwidth, without need to measure individual modal indices. The modal birefringence decreases with increasing wavelength. The spectropolarimetric interferometer was demonstrated to be responsive to changes occurring within the penetration depth of the evanescent field. A refractive-index change of Deltan = 0.002 was easily detected in the case of a 2-cm-long interaction path length.

  5. Tackling speaking mode varieties in EMG-based speech recognition.

    Science.gov (United States)

    Wand, Michael; Janke, Matthias; Schultz, Tanja

    2014-10-01

    An electromyographic (EMG) silent speech recognizer is a system that recognizes speech by capturing the electric potentials of the human articulatory muscles, thus enabling the user to communicate silently. After having established a baseline EMG-based continuous speech recognizer, in this paper, we investigate speaking mode variations, i.e., discrepancies between audible and silent speech that deteriorate recognition accuracy. We introduce multimode systems that allow seamless switching between audible and silent speech, investigate different measures which quantify speaking mode differences, and present the spectral mapping algorithm, which improves the word error rate (WER) on silent speech by up to 14.3% relative. Our best average silent speech WER is 34.7%, and our best WER on audibly spoken speech is 16.8%.

  6. Dynamic Sliding Mode Control based on Fractional calculus subject to uncertain delay based chaotic pneumatic robot

    OpenAIRE

    P., Sara Gholipour; Sh, Heydar Toosian

    2013-01-01

    This paper considers the chattering problem of sliding mode control while delay in robot manipulator caused chaos in such electromechanical systems. Fractional calculus as a powerful theorem to produce a novel sliding mode; which has a dynamic essence is used for chattering elimination. To realize the control of a class of chaotic systems in master-slave configuration this novel fractional dynamic sliding mode control scheme is presented and examined on delay based chaotic robot in joint and ...

  7. Normal mode-based approaches in receptor ensemble docking.

    Science.gov (United States)

    Cavasotto, Claudio N

    2012-01-01

    Explicitly accounting for target flexibility in docking still constitutes a difficult challenge due to the high dimensionality of the conformational space to be sampled. This especially applies to the high-throughput scenario, where the screening of hundreds of thousands compounds takes place. The use of multiple receptor conformations (MRCs) to perform ensemble docking in a sequential fashion is a simple but powerful approach that allows to incorporate binding site structural diversity in the docking process. Whenever enough experimental structures to build a diverse ensemble are not available, normal mode analysis provides an appealing and efficient approach to in silico generate MRCs by distortion along few low-frequency modes that represent collective mid- and large-scale displacements. In this way, the dimension of the conformational space to be sampled is heavily reduced. This methodology is especially suited to incorporate target flexibility at the backbone level. In this chapter, the main components of normal mode-based approaches in the context of ensemble docking are presented and explained, including the theoretical and practical considerations needed for the successful development and implementation of this methodology.

  8. Characterizing the differential mode group delay and modal dispersion of long few-mode fiber based on electrical spectral interferometry

    Science.gov (United States)

    Li, Jianping; Zhou, Yanqing; Luo, Jiawei; Feng, Yuanhua; Li, Zhaohui

    2017-03-01

    We experimentally demonstrate a fast, simple, and accurate method based on the electrical spectral interferometry for measuring the differential mode group delay (DMGD) and chromatic dispersion (CD) between the higher order modes and the fundamental mode in a 5-km few-mode fiber (FMF). The interferogram information of multiple modes of the measured FMF is recorded and used to deduce the relative delay by applying the FFT processing with a simple mathematical algorithm. Based on the acquired relative delay of different fiber modes, the DMGD and CD can be obtained about (2.27 to 2.36) ps/m, (1.4 to 2.3) ps/nm.km for LP11 mode and (4.56 to 4.68) ps/m, (-1.1 to 1) ps/nm.km for LP21 mode, respectively, for this tested FMF. At the same time, a precision of ±0.0015 ps/m for DMGD measurement has been achieved. The experimental results show that the demonstrated method could be a good solution to the characterization of FMF used in large capacity SDM transmission systems.

  9. Research on high-temperature sensing characteristics based on modular interference of single-mode multimode single-mode fiber

    Science.gov (United States)

    Peng, Zhaozhuang; Wang, Li; Yan, Huanhuan

    2016-11-01

    Application of high temperature fiber sensing system is very extensive. It can be mainly used in high temperature test aerospace, such as, materials, chemicals, and energy. In recent years, various on-line optical fiber interferometric sensors based on modular interference of single-mode-multimode-single-mode(SMS) fiber have been largely explored in high temperature fiber sensor. In this paper we use the special fiber of a polyimide coating, its sensor head is composed of a section of multimode fiber spliced in the middle of Single-mode fiber. When the light is launched into the multimode fiber(MMF) through the lead-in single-mode fiber(SMF), the core mode and cladding modes are excited and propagate in the MMF respectively. Then, at the MMF-SMF spliced point, the excited cladding modes coupled back into the core of lead-out SMF interfere with SMF core mode. And the wavelength of the interference dip would shift differently with the variation of the temperature. By this mean, we can achieve the measurement of temperature. The experimental results also show that the fiber sensor based on SMS structure has a highly temperature sensitivity. From 30° to 300°, with the temperature increasing, the interference dip slightly shifts toward longer wavelength and the temperature sensitivity coefficient is 0.0115nm/°. With high sensitivity, simple structure, immunity to electromagnetic interferences and a good linearity of the experimental results, the structure has an excellent application prospect in engineering field.

  10. Mode-Tracking Based Stationary-Point Optimization

    CERN Document Server

    Bergeler, Maike; Reiher, Markus

    2014-01-01

    In this work, we present a transition-state optimization protocol based on the Mode-Tracking algorithm [J. Chem. Phys. 118 (2003) 1634]. By calculating only the eigenvector of interest instead of diagonalizing the full Hessian matrix and performing an eigenvector following search based on the selectively calculated vector, we can efficiently optimize transition-state structures. The initial guess structures and eigenvectors are either chosen from a linear interpolation between the reactant and product structures, from a nudged-elastic band search, from a constrained-optimization scan, or from the minimum-energy structures. Alternatively, initial guess vectors based on chemical intuition may be defined. We then iteratively refine the selected vectors by the Davidson subspace iteration technique. This procedure accelerates finding transition states for large molecules of a few hundred atoms. It is also beneficial in cases where the starting structure is very different from the transition-state structure or wher...

  11. Experimental phase-space-based optical amplification of scar modes

    CERN Document Server

    Michel, Claire; Doya, Valerie; Aschieri, Pierre; Blanc, Wilfried; Legrand, Olivier; Mortessagne, Fabrice

    2012-01-01

    Waves billiard which are chaotic in the geometrical limit are known to support non-generic spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in micro-cavity lasers and vertically-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in their wave analogous phase space representation, we report experimental results of scar modes selection by gain in a doped D-shaped optical fiber.

  12. Characteristics of the transmission spectrum of the long period fiber gratings based on the coupling of core mode to the higher order cladding modes

    Institute of Scientific and Technical Information of China (English)

    Zijia Zhang(张自嘉); Wenkang Shi(施文康)

    2003-01-01

    The characteristics of the transmission spectrum of the Long-period fiber gratings (LPFGs) based on thecoupling of core mode to a higher order cladding mode (HE mode) are investigated using the coupled modetheory. This kind of LPFGs is different from that based on the coupling of core mode to a lower ordercladding mode because of the effect of the coupling of core mode to EH cladding mode. When the claddingmode order is higher, the coupling coefficients of core mode to HE and EH cladding modes are comparableand both of the propagation constants of HE and EH cladding modes approach, so the spectrum has anadditional loss peak. The bandwidth of LPFG based on the coupling of core mode to different claddingmode differs greatly. With the change of the mode orders from lower to higher, the transmission spectrumchanges from narrow to wide and more narrow.

  13. Erbium-doped fiber ring laser based on few-mode-singlemode-few-mode fiber structure for refractive index measurement

    Science.gov (United States)

    Liu, Jingxuan; Wang, Muguang; Liang, Xiao; Dong, Yue; Xiao, Han; Jian, Shuisheng

    2017-08-01

    A novel Erbium-doped fiber ring cavity laser sensor for refractive index (RI) measurement based on a special designed few-mode-singlemode-few-mode structure is proposed and experimentally demonstrated. The few-mode fiber is a home-made concentric ring core fiber (CRCF) which can only support two scalar modes. Thus a stable mode interference occurs which functions as a sensing head and band-pass filter to select the lasing wavelength simultaneously. A sensitivity of -45.429 nm/RIU is obtained in the range of 1.333-1.363. High optical signal to noise ratio (OSNR) of ∼45 dB and narrow 3-dB bandwidth of ∼0.1 nm indicate that the fiber ring laser sensing system has a high resolution and accuracy RI measurement.

  14. GA-Based Fuzzy Sliding Mode Controller for Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    W. L. Chiang

    2008-11-01

    Full Text Available Generally, the greatest difficulty encountered when designing a fuzzy sliding mode controller (FSMC or an adaptive fuzzy sliding mode controller (AFSMC capable of rapidly and efficiently controlling complex and nonlinear systems is how to select the most appropriate initial values for the parameter vector. In this paper, we describe a method of stability analysis for a GA-based reference adaptive fuzzy sliding model controller capable of handling these types of problems for a nonlinear system. First, we approximate and describe an uncertain and nonlinear plant for the tracking of a reference trajectory via a fuzzy model incorporating fuzzy logic control rules. Next, the initial values of the consequent parameter vector are decided via a genetic algorithm. After this, an adaptive fuzzy sliding model controller, designed to simultaneously stabilize and control the system, is derived. The stability of the nonlinear system is ensured by the derivation of the stability criterion based upon Lyapunov's direct method. Finally, an example, a numerical simulation, is provided to demonstrate the control methodology.

  15. Mode-converter and multiplexer based on SOI technology for few-mode fiber at 1550 nm

    Science.gov (United States)

    Garcia-Rodriguez, David; Corral, Juan L.; Griol, Amadeu; Llorente, Roberto

    2017-01-01

    The Asymmetric Directional Coupler (ADC) based on SOI (Silicon-on-Insulator) technology converts and couples the fundamental mode to the first higher order mode. The ADC is designed to achieve phase-matching condition, which is accomplished when both propagation constants are equal in each waveguide arm. Devices are fabricated in a SOI wafer with a 220 nm thick silicon layer. The refractive indexes of Si and SiO2 are nSi=3.47 and nSi02=1.46 respectively. The access waveguides (W1=0.45 μm) have been designed to propagate just the fundamental mode, TE0. The optimum width for the second waveguide was chosen to achieve the phase-matching condition for the TE1 mode, which corresponds to W2=0.962 μm. The coupling to the input and output waveguides is achieved through grating couplers. The input grating coupler will need to couple the LP01 mode from the SSMF (Standard Single-Mode Fiber) to the TE0 mode in the SOI waveguide; thus a typical design for a SOI coupler can be used. However, the output coupler must simultaneously couple the TE0 and TE1 modes in the SOI wide waveguide to the LP01 and LP11 modes in the FMF (Few-Mode Fiber). Input gratings are designed to have an area of 12x12 μm2 and a period of Λ=610 nm in order to maximize the optical power coupled between the fiber and the waveguide for an incident angle of 10 degrees. Output gratings are designed with the same period but distinct area (12.5x12.5 μm2) to correctly couple the LP01 and LP11 modes in the FMF.

  16. On-chip Mode Multiplexer Based on a Single Grating Coupler

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Xu, Jing;

    2012-01-01

    A two-mode multiplexer based on a single grating coupler is proposed and demonstrated on a silicon chip. The LP01 and LP11 modes of a few-mode fiber are excited from TE0 and TE1 silicon waveguide modes....

  17. Maximum Power Point Tracking Based on Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Nimrod Vázquez

    2015-01-01

    Full Text Available Solar panels, which have become a good choice, are used to generate and supply electricity in commercial and residential applications. This generated power starts with the solar cells, which have a complex relationship between solar irradiation, temperature, and output power. For this reason a tracking of the maximum power point is required. Traditionally, this has been made by considering just current and voltage conditions at the photovoltaic panel; however, temperature also influences the process. In this paper the voltage, current, and temperature in the PV system are considered to be a part of a sliding surface for the proposed maximum power point tracking; this means a sliding mode controller is applied. Obtained results gave a good dynamic response, as a difference from traditional schemes, which are only based on computational algorithms. A traditional algorithm based on MPPT was added in order to assure a low steady state error.

  18. Feasibility of Haze Governance Based on Carbon Sink Mode

    Institute of Scientific and Technical Information of China (English)

    Jie; HE; Quanquan; WANG

    2015-01-01

    In recent years,there are research findings of haze formation in various fields of academic circle. It has proved that causes of haze take on diverse characteristics. Thus,from both the natural and human perspective,haze governance should be diverse. Research conclusions on causes of haze formation mainly focus on special geographical structure,and meteorological factors such as relatively stable atmosphere,high rate of calm wind,high relative humidity and temperature of air,and human factors such as industrial pollution,automotive exhaust emissions,aerosol pollution,eutrophication of soil water,and change of city underlying surface. Carbon sink mode is a new channel for haze governance.In carbon sink mode,it is feasible to regulate relative humidity and temperature in air,enhance global wind,and reduce fine particles and microorganisms of air pollution,so as to reduce haze pollution. Besides,China’s special potential of carbon sink market makes it possible to govern haze on the base of carbon sink.

  19. Longitudinal tire force estimation based on sliding mode observer

    Energy Technology Data Exchange (ETDEWEB)

    El Hadri, A.; Cadiou, J.C.; M' Sirdi, N.K. [Versailles Univ., Paris (France). Lab. de Robotique; Beurier, G.; Delanne, Y. [Lab. Central des Ponts, Centre de Nantes (France)

    2001-07-01

    This paper presents an estimation method for vehicle longitudinal dynamics, particularly the tractive/braking force. The estimation can be used to detect a critical driving situation to improve security. It can be used also in several vehicle control systems. The main characteristics of the vehicle longitudinal dynamics were taken into account in the model used to design an observer and computer simulations. The state variables are the angular wheel velocity, vehicle velocity and the longitudinal tire force. The proposed differential equation of the tractive/braking force is derived using the concept of relaxation length. The observer designed is based on the sliding mode approach using only the angular wheel velocity measurement. The proposed method of estimation is verified through a one-wheel simulation model with a ''Magic formula'' tire model. Simulations results show an excellent reconstruction of the tire force. (orig.)

  20. Kinect-Based Sliding Mode Control for Lynxmotion Robotic Arm

    Directory of Open Access Journals (Sweden)

    Ismail Ben Abdallah

    2016-01-01

    Full Text Available Recently, the technological development of manipulator robot increases very quickly and provides a positive impact to human life. The implementation of the manipulator robot technology offers more efficiency and high performance for several human’s tasks. In reality, efforts published in this context are focused on implementing control algorithms with already preprogrammed desired trajectories (passive robots case or trajectory generation based on feedback sensors (active robots case. However, gesture based control robot can be considered as another channel of system control which is not widely discussed. This paper focuses on a Kinect-based real-time interactive control system implementation. Based on LabVIEW integrated development environment (IDE, a developed human-machine-interface (HMI allows user to control in real time a Lynxmotion robotic arm. The Kinect software development kit (SDK provides a tool to keep track of human body skeleton and abstract it into 3-dimensional coordinates. Therefore, the Kinect sensor is integrated into our control system to detect the different user joints coordinates. The Lynxmotion dynamic has been implemented in a real-time sliding mode control algorithm. The experimental results are carried out to test the effectiveness of the system, and the results verify the tracking ability, stability, and robustness.

  1. Microwave Photonics Systems Based on Whispering-gallery-mode Resonators

    Science.gov (United States)

    Coillet, Aurélien; Henriet, Rémi; Phan Huy, Kien; Jacquot, Maxime; Furfaro, Luca; Balakireva, Irina; Larger, Laurent; Chembo, Yanne K.

    2013-01-01

    Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various areas of technology and applied science, such as aerospace and communication engineering, sensing, metrology, nonlinear photonics, and quantum optics. In this article, we present the principal techniques used in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators. First detailed in this article is the protocol for resonator polishing, which is based on a grind-and-polish technique close to the ones used to polish optical components such as lenses or telescope mirrors. Then, a white light interferometric profilometer measures surface roughness, which is a key parameter to characterize the quality of the polishing. In order to launch light in the resonator, a tapered silica fiber with diameter in the micrometer range is used. To reach such small diameters, we adopt the "flame-brushing" technique, using simultaneously computer-controlled motors to pull the fiber apart, and a blowtorch to heat the fiber area to be tapered. The resonator and the tapered fiber are later approached to one another to visualize the resonance signal of the whispering gallery modes using a wavelength-scanning laser. By increasing the optical power in the resonator, nonlinear phenomena are triggered until the formation of a Kerr optical frequency comb is observed with a spectrum made of equidistant spectral lines. These Kerr comb spectra have exceptional characteristics that are suitable for several applications in science and technology. We consider the application related to ultra-stable microwave frequency synthesis and demonstrate the generation of a Kerr comb with GHz intermodal frequency. PMID:23963358

  2. Microwave photonics systems based on whispering-gallery-mode resonators.

    Science.gov (United States)

    Coillet, Aurélien; Henriet, Rémi; Phan Huy, Kien; Jacquot, Maxime; Furfaro, Luca; Balakireva, Irina; Larger, Laurent; Chembo, Yanne K

    2013-08-05

    Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various areas of technology and applied science, such as aerospace and communication engineering, sensing, metrology, nonlinear photonics, and quantum optics. In this article, we present the principal techniques used in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators. First detailed in this article is the protocol for resonator polishing, which is based on a grind-and-polish technique close to the ones used to polish optical components such as lenses or telescope mirrors. Then, a white light interferometric profilometer measures surface roughness, which is a key parameter to characterize the quality of the polishing. In order to launch light in the resonator, a tapered silica fiber with diameter in the micrometer range is used. To reach such small diameters, we adopt the "flame-brushing" technique, using simultaneously computer-controlled motors to pull the fiber apart, and a blowtorch to heat the fiber area to be tapered. The resonator and the tapered fiber are later approached to one another to visualize the resonance signal of the whispering gallery modes using a wavelength-scanning laser. By increasing the optical power in the resonator, nonlinear phenomena are triggered until the formation of a Kerr optical frequency comb is observed with a spectrum made of equidistant spectral lines. These Kerr comb spectra have exceptional characteristics that are suitable for several applications in science and technology. We consider the application related to ultra-stable microwave frequency synthesis and demonstrate the generation of a Kerr comb with GHz intermodal frequency.

  3. Design of Three-mode Multi/Demultiplexer Based on 2-D Photonic Crystals for Mode-Division Multiplexing Transmission

    Science.gov (United States)

    Fu, PeiDong; Chen, Heming

    2017-06-01

    A three mode division multiplexer and demultiplexer (MMUX/DEMMUX) base on 2-D photonic crystal at 1550 nm was designed. Two asymmetrical directional couplers are included in this MMUX/DEMMUX, which can achieve modes conversion function of TE0, TE1 and TE2 modes. In order to avoid phase mismatching in bus waveguide, taper directional is applied at waveguide junction which can reduce the insertion loss effectively. Plane waves method (PWM) and finite difference time domain (FDTD) methods were used to simulating the performance of MMUX/DEMMUX. Numerical simulations show that the designed device has the potential for high-capacity MDM optical communication systems with a low insertion loss (<0.27dB) and a low mode crosstalk (< -25.4 dB).

  4. Loosen Couple Workflow Mode of Lean Operator Improvement Based on Positive Feedback

    Directory of Open Access Journals (Sweden)

    Yao Li

    2013-04-01

    Full Text Available In order to promote the core competitive power for telecom operating enterprises to face market fine operation, this article compares the ECTA mode (Extension Case Transmission Mode and the LCA mode (Loosen Couple Mode, both of which are promoted by WfMC. By comparing these two modes, the suitable situations for these two modes are determined. We also carry out empirical analysis based on the customization mode of mobile phones between China telecom and mobile phone manufacturers and to expound the ascension effect of mechanism based on the agile telecom loose coupling workflow with positive feedback to the telecom enterprises. Finally, on the basis of positive feedback system, the task complexity and information transparency of LCA mode are improved, so that the semantics of public flow mode is kept unchanged and the sub workflow is optimized when modifying the sub workflow.

  5. Modeling the interdependent network based on two-mode networks

    Science.gov (United States)

    An, Feng; Gao, Xiangyun; Guan, Jianhe; Huang, Shupei; Liu, Qian

    2017-10-01

    Among heterogeneous networks, there exist obviously and closely interdependent linkages. Unlike existing research primarily focus on the theoretical research of physical interdependent network model. We propose a two-layer interdependent network model based on two-mode networks to explore the interdependent features in the reality. Specifically, we construct a two-layer interdependent loan network and develop several dependent features indices. The model is verified to enable us to capture the loan dependent features of listed companies based on loan behaviors and shared shareholders. Taking Chinese debit and credit market as case study, the main conclusions are: (1) only few listed companies shoulder the main capital transmission (20% listed companies occupy almost 70% dependent degree). (2) The control of these key listed companies will be more effective of avoiding the spreading of financial risks. (3) Identifying the companies with high betweenness centrality and controlling them could be helpful to monitor the financial risk spreading. (4) The capital transmission channel among Chinese financial listed companies and Chinese non-financial listed companies are relatively strong. However, under greater pressure of demand of capital transmission (70% edges failed), the transmission channel, which constructed by debit and credit behavior, will eventually collapse.

  6. Genetic algorithm based two-mode clustering of metabolomics data

    NARCIS (Netherlands)

    Hageman, J.A.; Berg, R.A. van den; Westerhuis, J.A.; Werf, M.J. van der; Smilde, A.K.

    2008-01-01

    Metabolomics and other omics tools are generally characterized by large data sets with many variables obtained under different environmental conditions. Clustering methods and more specifically two-mode clustering methods are excellent tools for analyzing this type of data. Two-mode clustering metho

  7. Relevant modes selection method based on Spearman correlation coefficient for laser signal denoising using empirical mode decomposition

    Science.gov (United States)

    Duan, Yabo; Song, Chengtian

    2016-10-01

    Empirical mode decomposition (EMD) is a recently proposed nonlinear and nonstationary laser signal denoising method. A noisy signal is broken down using EMD into oscillatory components that are called intrinsic mode functions (IMFs). Thresholding-based denoising and correlation-based partial reconstruction of IMFs are the two main research directions for EMD-based denoising. Similar to other decomposition-based denoising approaches, EMD-based denoising methods require a reliable threshold to determine which IMFs are noise components and which IMFs are noise-free components. In this work, we propose a new approach in which each IMF is first denoised using EMD interval thresholding (EMD-IT), and then a robust thresholding process based on Spearman correlation coefficient is used for relevant modes selection. The proposed method tackles the problem using a thresholding-based denoising approach coupled with partial reconstruction of the relevant IMFs. Other traditional denoising methods, including correlation-based EMD partial reconstruction (EMD-Correlation), discrete Fourier transform and wavelet-based methods, are investigated to provide a comparison with the proposed technique. Simulation and test results demonstrate the superior performance of the proposed method when compared with the other methods.

  8. Relevant modes selection method based on Spearman correlation coefficient for laser signal denoising using empirical mode decomposition

    Science.gov (United States)

    Duan, Yabo; Song, Chengtian

    2016-12-01

    Empirical mode decomposition (EMD) is a recently proposed nonlinear and nonstationary laser signal denoising method. A noisy signal is broken down using EMD into oscillatory components that are called intrinsic mode functions (IMFs). Thresholding-based denoising and correlation-based partial reconstruction of IMFs are the two main research directions for EMD-based denoising. Similar to other decomposition-based denoising approaches, EMD-based denoising methods require a reliable threshold to determine which IMFs are noise components and which IMFs are noise-free components. In this work, we propose a new approach in which each IMF is first denoised using EMD interval thresholding (EMD-IT), and then a robust thresholding process based on Spearman correlation coefficient is used for relevant modes selection. The proposed method tackles the problem using a thresholding-based denoising approach coupled with partial reconstruction of the relevant IMFs. Other traditional denoising methods, including correlation-based EMD partial reconstruction (EMD-Correlation), discrete Fourier transform and wavelet-based methods, are investigated to provide a comparison with the proposed technique. Simulation and test results demonstrate the superior performance of the proposed method when compared with the other methods.

  9. Tunable orbital angular momentum mode filter based on optical geometric transformation.

    Science.gov (United States)

    Huang, Hao; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Yue, Yang; Ahmed, Nisar; Lavery, Martin P J; Padgett, Miles J; Dolinar, Sam; Tur, Moshe; Willner, Alan E

    2014-03-15

    We present a tunable mode filter for spatially multiplexed laser beams carrying orbital angular momentum (OAM). The filter comprises an optical geometric transformation-based OAM mode sorter and a spatial light modulator (SLM). The programmable SLM can selectively control the passing/blocking of each input OAM beam. We experimentally demonstrate tunable filtering of one or multiple OAM modes from four multiplexed input OAM modes with vortex charge of ℓ=-9, -4, +4, and +9. The measured output power suppression ratio of the propagated modes to the blocked modes exceeds 14.5 dB.

  10. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide.

    Science.gov (United States)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan; Peucheret, Christophe

    2014-01-13

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due to phase mismatch. A two-mode division multiplexing circuit with tapered directional coupler based (de)multiplexers and a multimode waveguide is designed and fabricated for this application. Experimental results show clear eye-diagrams and moderate power penalties for the wavelength conversion of both modes.

  11. The TriLab, a Novel ICT Based Triple Access Mode Laboratory Education Model

    Science.gov (United States)

    Abdulwahed, Mahmoud; Nagy, Zoltan K.

    2011-01-01

    This paper introduces a novel model of laboratory education, namely the TriLab. The model is based on recent advances in ICT and implements a three access modes to the laboratory experience (virtual, hands-on and remote) in one software package. A review of the three modes is provided with highlights of advantages and disadvantages of each mode.…

  12. Protein-based flexible whispering gallery mode resonators

    Science.gov (United States)

    Yilmaz, Huzeyfe; Pena-Francesch, Abdon; Xu, Linhua; Shreiner, Robert; Jung, Huihun; Huang, Steven H.; Özdemir, Sahin K.; Demirel, Melik C.; Yang, Lan

    2016-02-01

    The idea of creating photonics tools for sensing, imaging and material characterization has long been pursued and many achievements have been made. Approaching the level of solutions provided by nature however is hindered by routine choice of materials. To this end recent years have witnessed a great effort to engineer mechanically flexible photonic devices using polymer substrates. On the other hand, biodegradability and biocompatibility still remains to be incorporated. Hence biomimetics holds the key to overcome the limitations of traditional materials in photonics design. Natural proteins such as sucker ring teeth (SRT) and silk for instance have remarkable mechanical and optical properties that exceed the endeavors of most synthetic and natural polymers. Here we demonstrate for the first time, toroidal whispering gallery mode resonators (WGMR) fabricated entirely from protein structures such as SRT of Loligo vulgaris (European squid) and silk from Bombyx mori. We provide here complete optical and material characterization of proteinaceous WGMRs, revealing high quality factors in microscale and enhancement of Raman signatures by a microcavity. We also present a most simple application of a WGMR as a natural protein add-drop filter, made of SRT protein. Our work shows that with protein-based materials, optical, mechanical and thermal properties can be devised at the molecular level and it lays the groundwork for future eco-friendly, flexible photonics device design.

  13. Active magnetic bearing system based on sliding mode control

    Science.gov (United States)

    Zhang, Yanhong

    2017-07-01

    A new sliding mode variable structure control algorithm suitable for active magnetic bearing is proposed, which is widely used for nonlinear control system. The model and controller is designed, simulation and experimental parts are also made, according to the switching function and the sliding mode control law. The current of electromagnet is adjusted to realize stable levitation of the rotor. The experimental result shows that the sliding mode variable structure controller is an effective way for magnetic bearing control, and the active magnetic bearing system is a highly nonlinear and advanced control method that can reduce the setting time and the cost.

  14. Based on Intelligent Robot of E-business Distribution Center Operation Mode Research

    OpenAIRE

    2016-01-01

    According to E-business distribution center operation mode in domestic and advanced experience drawing lessons at home and abroad, this paper based on intelligent robot researches E-business distribution center operation mode. And it proposes the innovation logistics storage in E-business and sorting integration system, and elaborates its principle, characteristics, as well as studies its business mode and logistics process, and its parameters and working mode of AGV equipment.

  15. [A 3D-ultrasound imaging system based on back-end scanning mode].

    Science.gov (United States)

    Qi, Jian; Chen, Yimin; Ding, Mingyue; Wei, Chiming

    2012-07-01

    A new scanning mode is proposed that the front-end of the probe is fixed, while the back-end makes fan-shaped, scanning movement. The new scanning mode avoided ribs drawbacks successfully. Based on the new scanning mode a 3D-Ultrasound Images System is accomplished to acquire 2D data of fetusfetus fetusfetus phantom and livers and kidneys, to demonstrates the effectiveness of the new scanning mode.

  16. Long-Period Fibre Grating Thin Film Sensors Based on Cladding Mode Coupling

    Institute of Scientific and Technical Information of China (English)

    XU Yan-Ping; GU Zheng-Tian; CHEN Jia-Bi

    2005-01-01

    @@ Based on a method of rigorous vector-field analysis, a numerical model of triple-clad long-period fibre grating is established. The vector components of the electric field for the HE11 cladding mode are plotted to study the field distribution of the cladding mode. The local intensity curves of the first six l = 1 cladding modes are also given. It is found that the low-order HE modes have a larger proportion of intensity localized in the core than the low-order EH modes, just like the double-clad LPFG. Further, the coupling constant between the core mode and the cladding mode is analysed. The results show that the coupling constant of the low-order HE increases monotonously when the mode number becomes larger, and it varies monotonously with the film thickness except for a certain specific region.

  17. Edge Feature Based Fast Mode Decision Algorithm for H.264 Intra Prediction

    Institute of Scientific and Technical Information of China (English)

    GAO Wei; LI Hua; ZHANG Shufang; HOU Ling; ZHANG Shujun

    2006-01-01

    A fast intra mode decision algorithm is proposed in this paper to reduce the complexity of H. 264 encoder. The proposed algorithm adopted the pre-processing method based on edge feature in pictures to filter out some impossible prediction modes. Context information and pre-computed threshold are used to determine whether it is necessary to check the DC mode. This method is able to get rid of most of candidate modes so that only 66-150 modes are left for the final mode decision, instead of 592 modes in the case of full search(FS)method of H. 264. Simulation results demonstrate that the coding time of the proposed algorithm falls down 71.7% compared with FS method, while the performance loss is trivial compared with FS mode decision scheme.

  18. A multi-mode operation control strategy for flexible microgrid based on sliding-mode direct voltage and hierarchical controls.

    Science.gov (United States)

    Zhang, Qinjin; Liu, Yancheng; Zhao, Youtao; Wang, Ning

    2016-03-01

    Multi-mode operation and transient stability are two problems that significantly affect flexible microgrid (MG). This paper proposes a multi-mode operation control strategy for flexible MG based on a three-layer hierarchical structure. The proposed structure is composed of autonomous, cooperative, and scheduling controllers. Autonomous controller is utilized to control the performance of the single micro-source inverter. An adaptive sliding-mode direct voltage loop and an improved droop power loop based on virtual negative impedance are presented respectively to enhance the system disturbance-rejection performance and the power sharing accuracy. Cooperative controller, which is composed of secondary voltage/frequency control and phase synchronization control, is designed to eliminate the voltage/frequency deviations produced by the autonomous controller and prepare for grid connection. Scheduling controller manages the power flow between the MG and the grid. The MG with the improved hierarchical control scheme can achieve seamless transitions from islanded to grid-connected mode and have a good transient performance. In addition the presented work can also optimize the power quality issues and improve the load power sharing accuracy between parallel VSIs. Finally, the transient performance and effectiveness of the proposed control scheme are evaluated by theoretical analysis and simulation results.

  19. Study of node and mass sensitivity of resonant mode based cantilevers with concentrated mass loading

    Science.gov (United States)

    Zhang, Kewei; Chai, Yuesheng; Fu, Jiahui

    2015-12-01

    Resonant-mode based cantilevers are an important type of acoustic wave based mass-sensing devices. In this work, the governing vibration equation of a bi-layer resonant-mode based cantilever attached with concentrated mass is established by using a modal analysis method. The effects of resonance modes and mass loading conditions on nodes and mass sensitivity of the cantilever were theoretically studied. The results suggested that the node did not shift when concentrated mass was loaded on a specific position. Mass sensitivity of the cantilever was linearly proportional to the square of the point displacement at the mass loading position for all the resonance modes. For the first resonance mode, when mass loading position xc satisfied 0 xc xc ≤ l. Mass sensitivity did not change when concentrated mass was loaded at the rigid end. This work can provide scientific guidance to optimize the mass sensitivity of a resonant-mode based cantilever.

  20. Resonant Inerter Based Absorbers for a Selected Global Mode

    DEFF Research Database (Denmark)

    Krenk, Steen

    2016-01-01

    The paper presents calibration and efficiency analyses for two different configurations of a resonant vibration absorber consisting of a spring, a damper and an inerter element. In the two configurations the damper is either in parallel with the spring or with the inerter element. A calibration......-resonant modes. The calibration procedure is given a unified format for the two absorber types, and the high efficiency – evaluated as the ability to reproduce the selected dynamic amplification level of the resonant mode – is demonstrated....

  1. Adaptive Sliding Mode Control Based on Uncertainty and Disturbance Estimator

    Directory of Open Access Journals (Sweden)

    Yue Zhu

    2014-01-01

    Full Text Available This paper presents an original adaptive sliding mode control strategy for a class of nonlinear systems on the basis of uncertainty and disturbance estimator. The nonlinear systems can be with parametric uncertainties as well as unmatched uncertainties and external disturbances. The novel adaptive sliding mode control has several advantages over traditional sliding mode control method. Firstly, discontinuous sign function does not exist in the proposed adaptive sliding mode controller, and it is not replaced by saturation function or similar approximation functions as well. Therefore, chattering is avoided in essence, and the chattering avoidance is not at the cost of reducing the robustness of the closed-loop systems. Secondly, the uncertainties do not need to satisfy matching condition and the bounds of uncertainties are not required to be unknown. Thirdly, it is proved that the closed-loop systems have robustness to parameter uncertainties as well as unmatched model uncertainties and external disturbances. The robust stability is analyzed from a second-order linear time invariant system to a nonlinear system gradually. Simulation on a pendulum system with motor dynamics verifies the effectiveness of the proposed method.

  2. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    Science.gov (United States)

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-01-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%.

  3. Mode-Selective Wavelength Conversion Based on Four-Wave Mixing in a Multimode Silicon Waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2013-01-01

    We report all-optical mode-selective wavelength conversion based on four-wave mixing in a multimode Si waveguide. A two-mode division multiplexing circuit using tapered directional coupler based (de)multiplexers is used for the application. Experimental results show clear eye-diagrams and moderate...

  4. Nonlinear adaptive control based on fuzzy sliding mode technique and fuzzy-based compensator.

    Science.gov (United States)

    Nguyen, Sy Dzung; Vo, Hoang Duy; Seo, Tae-Il

    2017-09-01

    It is difficult to efficiently control nonlinear systems in the presence of uncertainty and disturbance (UAD). One of the main reasons derives from the negative impact of the unknown features of UAD as well as the response delay of the control system on the accuracy rate in the real time of the control signal. In order to deal with this, we propose a new controller named CO-FSMC for a class of nonlinear control systems subjected to UAD, which is constituted of a fuzzy sliding mode controller (FSMC) and a fuzzy-based compensator (CO). Firstly, the FSMC and CO are designed independently, and then an adaptive fuzzy structure is discovered to combine them. Solutions for avoiding the singular cases of the fuzzy-based function approximation and reducing the calculating cost are proposed. Based on the solutions, fuzzy sliding mode technique, lumped disturbance observer and Lyapunov stability analysis, a closed-loop adaptive control law is formulated. Simulations along with a real application based on a semi-active train-car suspension are performed to fully evaluate the method. The obtained results reflected that vibration of the chassis mass is insensitive to UAD. Compared with the other fuzzy sliding mode control strategies, the CO-FSMC can provide the best control ability to reduce unwanted vibrations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Research on the Formation Modes of Emerging Technologies Based on the Species Origin Theory

    Institute of Scientific and Technical Information of China (English)

    SONG Yan; YIN Lu

    2006-01-01

    Based on the research on emerging technologies and "the technology species", this thesis tries to find out the homologous relations between emerging technology and new species. The theory of the new biology species in synthetic evolution and the modern genetics is referred in the research. The modes of forming emerging technologies are discussed through some examples of IT evolvement according to modes of the biology speciation. Finally, it is pointed out that the biology species origin theory can analogize continuously the research about the evolvement mode of every emerging technology, and the implications have been bought to enterprises based on the formation conditions of each mode.

  6. GEARBOX FAULT DIAGNOSIS BASED ON EMPIRICAL MODE DECOMPOSITION

    Institute of Scientific and Technical Information of China (English)

    Shen Guoji; Tao Limin; Chen Zhongsheng

    2004-01-01

    Time synchronous averaging of vibration data is a fundament technique for gearbox diagnosis. Currently, this technique relies on hardware tachometer to give phase synchronous information. Empirical mode decomposition (EMD) is introduced to replace time synchronous averaging of gearbox vibration signal. With it, any complicated dataset can be decomposed into a finite and often small number of intrinsic mode functions (IMF). The key problem is how to assure that vibration signals deduced by gear defects could be sifted out by EMD. The characteristic vibration signals of gear defects are proved IMFs, which makes it possible to utilize EMD for the diagnosis of gearbox faults. The method is validated by data from recordings of the vibration of a single-stage spiral bevel gearbox with fatigue pitting. The results show EMD is powerful to extract characteristic information from noisy vibration signals.

  7. Theoretic base of Edge Local Mode triggering by vertical displacements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China); Wu, N.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

    2015-05-15

    Vertical instability is studied with R-dependent displacement. For Solovev's configuration, the stability boundary of the vertical instability is calculated. The pressure gradient is a destabilizing factor which is contrary to Rebhan's result. Equilibrium parallel current density, j{sub //}, at plasma boundary is a drive of the vertical instability similar to Peeling-ballooning modes; however, the vertical instability cannot be stabilized by the magnetic shear which tends towards infinity near the separatrix. The induced current observed in the Edge Local Mode (ELM) triggering experiment by vertical modulation is derived. The theory provides some theoretic explanation for the mitigation of type-I ELMS on ASDEX Upgrade. The principle could be also used for ITER.

  8. A Novel Mixed-Mode CCII-Based Filter

    Directory of Open Access Journals (Sweden)

    Muhammad Taher Abuelma'atti

    2004-01-01

    Full Text Available A new mixed-mode biquad circuit is presented. The circuit uses five second-generation current conveyors, seven resistors, and two grounded capacitors and can realize lowpass, highpass, bandpass , notch, lowpass notch, highpass notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. The parameters ωo and ωo/Qo enjoy independent electronic tunability. Simulation results are included.

  9. Liquid level sensor based on fiber ring laser with single-mode-offset coreless-single-mode fiber structure

    Science.gov (United States)

    Wang, Zixiao; Tan, Zhongwei; Xing, Rui; Liang, Linjun; Qi, Yanhui; Jian, Shuisheng

    2016-10-01

    A novel reflective liquid level sensor based on single-mode-offset coreless-single-mode (SOCS) fiber structure is proposed and experimentally demonstrated. Theory analyses and experimental results indicate that offset fusion can remarkably enhance the sensitivity of sensor. Ending-reflecting structure makes the sensor compact and easy to deploy. Meanwhile, we propose a laser sensing system, and the SOCS structure is used as sensing head and laser filter simultaneously. Experimental results show that laser spectra with high optical signal-to-noise ratio (-30 dB) and narrow 3-dB bandwidth (<0.15 nm) are achieved. Various liquids with different indices are used for liquid level sensing, besides, the refractive index sensitivity is also investigated. In measurement range, the sensing system presents steady laser output.

  10. Mode Conversion Behavior of Guided Wave in a Pipe Inspection System Based on a Long Waveguide.

    Science.gov (United States)

    Sun, Feiran; Sun, Zhenguo; Chen, Qiang; Murayama, Riichi; Nishino, Hideo

    2016-10-19

    To make clear the mode conversion behavior of S0-mode lamb wave and SH0-plate wave converting to the longitudinal mode guided wave and torsional mode guided wave in a pipe, respectively, the experiments were performed based on a previous built pipe inspection system. The pipe was wound with an L-shaped plate or a T-shaped plate as the waveguide, and the S0-wave and SH0-wave were excited separately in the waveguide. To carry out the objective, a meander-line coil electromagnetic acoustic transducer (EMAT) for S0-wave and a periodic permanent magnet (PPM) EMAT for SH0-wave were developed and optimized. Then, several comparison experiments were conducted to compare the efficiency of mode conversion. Experimental results showed that the T(0,1) mode, L(0,1) mode, and L(0,2) mode guided waves can be successfully detected when converted from the S0-wave or SH0-wave with different shaped waveguides. It can also be inferred that the S0-wave has a better ability to convert to the T(0,1) mode, while the SH0-wave is easier to convert to the L(0,1) mode and L(0,2) mode, and the L-shaped waveguide has a better efficiency than T-shaped waveguide.

  11. Mode Conversion Behavior of Guided Wave in a Pipe Inspection System Based on a Long Waveguide

    Directory of Open Access Journals (Sweden)

    Feiran Sun

    2016-10-01

    Full Text Available To make clear the mode conversion behavior of S0-mode lamb wave and SH0-plate wave converting to the longitudinal mode guided wave and torsional mode guided wave in a pipe, respectively, the experiments were performed based on a previous built pipe inspection system. The pipe was wound with an L-shaped plate or a T-shaped plate as the waveguide, and the S0-wave and SH0-wave were excited separately in the waveguide. To carry out the objective, a meander-line coil electromagnetic acoustic transducer (EMAT for S0-wave and a periodic permanent magnet (PPM EMAT for SH0-wave were developed and optimized. Then, several comparison experiments were conducted to compare the efficiency of mode conversion. Experimental results showed that the T(0,1 mode, L(0,1 mode, and L(0,2 mode guided waves can be successfully detected when converted from the S0-wave or SH0-wave with different shaped waveguides. It can also be inferred that the S0-wave has a better ability to convert to the T(0,1 mode, while the SH0-wave is easier to convert to the L(0,1 mode and L(0,2 mode, and the L-shaped waveguide has a better efficiency than T-shaped waveguide.

  12. Design and optimization of mode converter based on long period fiber grating

    Science.gov (United States)

    Xiang, Qian; Chang, Li-Jun; Chen, Ming-Yang

    2016-10-01

    A novel mode converter which is based on long period fiber grating (LPFG) is proposed. A graded-index optical fiber is introduced to induce strong mode coupling at wide bandwidth. By optimize the fiber configuration and parameters, and the appropriate choice of grating parameter, high mode conversion efficiency with cross-talk lower than -20 dB and wide operation bandwidth over 180 nm can be achieved.

  13. Mode decoupling in solid state ring laser based on stimulated Raman effect in polar crystals

    Institute of Scientific and Technical Information of China (English)

    Luo Zhang; Yuan Xiao-Dong; Ye Wei-Min; Zeng Chun; Ji Jia-Rong

    2011-01-01

    In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in order to realize solid state ring laser gyroscopes. We theoretically investigate the mode coupling induced by gain saturation between clockwise (CW) and counterclockwise (CCW) propagating laser modes. Because the CW and CCW running waves are pumped with counter-propagating lasers respectively, the independent coexistence can be ensured.

  14. Electromechanical instrument collaborative sharing system based on A/S mode

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying; YANG Yu; XIE Qiu; YUAN Qianbin; LIU Fei

    2006-01-01

    In this paper, we put forward a collaborative mode based on A/S mode to solve existing problems in the process of developing electromechanical instrument collaborative sharing system (EICSS). The mode architecture, working pattern and development flow of this system were described. The prototype system developed was applied to Lambda 900 Spectrometer in Chongqing University to realize electromechanical instrument networked sharing, and demonstrated desirable expansibility and felxibility to satisfy diverse demands of customers.

  15. State-of-the-art piezoelectric transformer-based switch mode power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    Inductorless switch mode power supplies based on piezoelectric transformers are used to replace conventional transformers in high power density switch mode power supplies. Even though piezoelectric-based converters exhibit a high d egree of nonlinearity, it is desirable to use piezoelectric transfo...... discusses power supplies with the trend evaluation of piezoelectric transformer-based converter topologies and control methods. The challenges of piezoelectric transformers regarding soft switching capability and nonlinearity are addressed. This paper can be used as a guideline f or choosing a proper...... topology of piezoelectric-based switch mode power supply and a control method for the required application....

  16. Observer Based Sliding Mode Attitude Control: Theoretical and Experimental Results

    Directory of Open Access Journals (Sweden)

    U. Jørgensen

    2011-07-01

    Full Text Available In this paper we present the design of a sliding mode controller for attitude control of spacecraft actuated by three orthogonal reaction wheels. The equilibrium of the closed loop system is proved to be asymptotically stable in the sense of Lyapunov. Due to cases where spacecraft do not have angular velocity measurements, an estimator for the generalized velocity is derived and asymptotic stability is proven for the observer. The approach is tested on an experimental platform with a sphere shaped Autonomous Underwater Vehicle SATellite: AUVSAT, developed at the Norwegian University of Science and Technology.

  17. SOl-based radial-contour-mode micromechanical disk resonator

    Institute of Scientific and Technical Information of China (English)

    Jia Yingqian; Zhao Zhengping; Yang Yongjun; Hu Xiaodong; Li Qian

    2011-01-01

    This paper reports a radial-contour-mode micromechanical disk resonator for radio frequency applications.This disk resonator with a gold plated layer as the electrodes,was prepared on a silicon-on-insulator wafer,which is supported by an anchor on another silicon wafer through Au-Au thermo-compression bonding.The gap between the disk and the surrounding gold electrodes is 100 nm.The radius of the disk is 20 μm and the thickness is 4.5μm.In results,the resonator shows a resonant frequency of 143 MHz and a quality factor of 5600 in vacuum.

  18. Design rules for lossy mode resonance based sensors.

    Science.gov (United States)

    Del Villar, Ignacio; Hernaez, Miguel; Zamarreño, Carlos R; Sánchez, Pedro; Fernández-Valdivielso, Carlos; Arregui, Francisco J; Matias, Ignacio R

    2012-07-01

    Lossy mode resonances can be obtained in the transmission spectrum of cladding removed multimode optical fiber coated with a thin-film. The sensitivity of these devices to changes in the properties of the coating or the surrounding medium can be optimized by means of the adequate parameterization of the coating refractive index, the coating thickness, and the surrounding medium refractive index. Some basic rules of design, which enable the selection of the best parameters for each specific sensing application, are indicated in this work.

  19. Improved Frame Mode Selection for AMR-WB+ Based on Decision Tree

    Science.gov (United States)

    Kim, Jong Kyu; Kim, Nam Soo

    In this letter, we propose a coding mode selection method for the AMR-WB+ audio coder based on a decision tree. In order to reduce computation while maintaining good performance, decision tree classifier is adopted with the closed loop mode selection results as the target classification labels. The size of the decision tree is controlled by pruning, so the proposed method does not increase the memory requirement significantly. Through an evaluation test on a database covering both speech and music materials, the proposed method is found to achieve a much better mode selection accuracy compared with the open loop mode selection module in the AMR-WB+.

  20. Global Mode-Based Control of Supersonic Jet Noise

    Science.gov (United States)

    Natarajan, Mahesh; Freund, Jonathan; Bodony, Daniel

    2015-11-01

    The loudest source of high-speed jet noise appears to be describable by unsteady wavepackets that resemble instabilities. We seek to reduce their acoustic impact by developing a novel control strategy that uses global modes to model their dynamics and structural sensitivity of the linearized compressible Navier-Stokes operator to determine effective linear feedback control. Using co-located actuators and sensors we demonstrate the method on an axisymmetric Mach 1.5 fitted with a nozzle. Direct numerical simulations using this control show significant noise reduction, with additional reduction with increase in control gain. Eigenanalysis of the uncontrolled and controlled mean flows reveal fundamental changes in the spectrum at frequencies lower than that used by the control. The non-normality of the global modes is shown to enable this control to affect a wide range of frequencies. The low-frequency wavepacket components are made less acoustically efficient, which is reflected in the far-field noise spectrum. Mean flow alterations are minor near the nozzle and only become apparent further downstream. Office of Naval Research and National Science Foundation.

  1. Evaluation of Bus Vibration Comfort Based on Passenger Crowdsourcing Mode

    Directory of Open Access Journals (Sweden)

    Hong Zhao

    2016-01-01

    Full Text Available Vibration comfort is an important factor affecting the quality of service (QoS of bus. In order to make people involved in supervising bus’s vibration comfort and improve passengers’ riding experience, a novel mode of passenger crowdsourcing is introduced. In this paper, comfort degree of bus vibration is calculated from bus’s vibration signals collected by passengers’ smartphones and sent through WiFi to the Boa web server which shows the vibration comfort on the LCD deployed in bus and maybe trigger alarm lamp when the vibration is beyond the threshold. Three challenges here have been overcome: firstly, space coordinate transformation algorithm is used to solve the constant drift of signals collected; secondly, a low-pass filter is designed to isolate gravity from signals real-timely via limited computing resources; thirdly, an embedded evaluation system is developed according to the calculation procedure specified by criterion ISO 2631-1997. Meanwhile, the model proposed is tested in a practical running environment, the vibration data in whole travel are recorded and analyzed offline. The results show that comfort degree of vibration obtained from the experimental system is identical with the truth, and this mode is proved to be effective.

  2. Passivity-based sliding mode control for a polytopic stochastic differential inclusion system.

    Science.gov (United States)

    Liu, Leipo; Fu, Zhumu; Song, Xiaona

    2013-11-01

    Passivity-based sliding mode control for a polytopic stochastic differential inclusion (PSDI) system is considered. A control law is designed such that the reachability of sliding motion is guaranteed. Moreover, sufficient conditions for mean square asymptotic stability and passivity of sliding mode dynamics are obtained by linear matrix inequalities (LMIs). Finally, two examples are given to illustrate the effectiveness of the proposed method.

  3. HARMONIC COMPONENT EXTRACTION FROM A CHAOTIC SIGNAL BASED ON EMPIRICAL MODE DECOMPOSITION METHOD

    Institute of Scientific and Technical Information of China (English)

    LI Hong-guang; MENG Guang

    2006-01-01

    A novel approach of signal extraction of a harmonic component from a chaotic signal generated by a Duffing oscillator was proposed. Based on empirical mode decomposition (EMD) and concept that any signal is composed of a series of the simple intrinsic modes, the harmonic components were extracted from the chaotic signals. Simulation results show the approach is satisfactory.

  4. Design of Multivalued Circuits Based on an Algebra for Current—Mode CMOS Multivalued Circuits

    Institute of Scientific and Technical Information of China (English)

    陈偕雄; ClaudioMoraga

    1995-01-01

    An algebra proposed for current-mode CMOS multivalued circuits is briefly reviewed.this paper discusses its application in the design of multivalued circuits.Several current-mode CMOS quaternary and quinary circuits are designed by algebraic means.The design method based on this algebra may offer a design simpler than the previously known ones.

  5. Discursive Modes and Their Pedagogical Functions in Model-Based Inquiry (MBI) Classrooms

    Science.gov (United States)

    Campbell, Todd; Oh, Phil Seok; Neilson, Drew

    2012-01-01

    This research investigated the emergent discursive modes and their pedagogical functions found in model-based inquiry (MBI) science classrooms. A sample of four high school physics classrooms was video-recorded and analysed using a newly established discourse mode analysis framework. Qualitative methods were employed to identify the most salient…

  6. Specialized Courses Teaching Mode Innovation of the Independent College Based on MOOCS

    Science.gov (United States)

    Hongxia, Sun; Na, Zhao; Zhixiang, Zhang; Feng, Li; Pengcheng, Zhu

    2017-01-01

    Independent college is a new kind of school-running pattern, on the basis of independent college computer professional course teaching, based on the background of MOOCS, specialized course teaching mode principle, on the basis of design is given priority to, the class online course of classroom teaching mode. To a certain extent can motivate we…

  7. Second-harmonic mode coupling in microresonator-based optical frequency comb generation

    CERN Document Server

    Xue, Xiaoxiao; Xuan, Yi; Jaramillo-Villegas, Jose A; Wang, Pei-Hsun; Leaird, Daniel E; Erkintalo, Miro; Qi, Minghao; Weiner, Andrew M

    2016-01-01

    Microresonator-based optical frequency comb (microcomb) generation can potentially achieve ultra-compact volume and low power consumption for portable applications. The comb formation is a consequence of cascaded four-wave-mixing due to the third-order Kerr nonlinearity. Mode coupling can affect the comb self-starting and mode-locking behaviors, resulting in complex dynamics that is far from well understood. Understanding the mechanism of mode coupling in comb generation proves highly important to achieve stable and robust microcomb sources. Here, we report a nonlinear mode coupling mechanism in microresonators with simultaneous second- and third-order nonlinearities. The nonlinear dynamics governed by the third-order nonlinearity is altered by second-harmonic mode coupling. As a demonstration of this effect, second-harmonic assisted coherent comb generation is achieved in the normal dispersion region, where comb creation is prohibited in the absence of mode coupling. Since second-order nonlinearity has been ...

  8. Effects of transverse mode coupling and optical confinement factor on gallium-nitride based laser diode

    Institute of Scientific and Technical Information of China (English)

    Jin Xiao-Ming; Zhang Bei; Dai Tao; Zhang Guo-Yi

    2008-01-01

    We have investigated the transverse mode pattern and the optical field confinement factor of gallium nitride (GaN) laser diodes (LDs) theoretically. For the particular LD structure, composed of approximate 4μm thick n-GaN substrate layer, the maximum optical confinement factor was found to be corresponding to the 5th order transverse mode, the so-called lasing mode. Moreover, the value of the maximum confinement factor varies periodically when increasing the n-side GaN layer thickness, which simultaneously changes and increases the oscillation mode order of the GaN LD caused by the effects of mode coupling. The effects of the thickness and the average composition of Al in the AlGaN/GaN superlattice on the optical confinement factor are also presented. Finally, the mode coupling and optimization of the layers in the GaN-based LD are discussed.

  9. Sensorless Control of a Stepper Motor Based on Higher Order Sliding Modes

    OpenAIRE

    Fiter, Christophe; Floquet, Thierry; Rudolph, Joachim

    2010-01-01

    International audience; A robust control for a stepper motor with no position nor velocity sensors and only needing current and voltage measurements is designed. Second order sliding mode based observers are realized to estimate both rotor angular position and velocity. Moreover, a robust control law, which is also based on second order sliding modes and which uses the estimates of the observer, is designed. The stability of the observer based control loop is discussed. The results obtained i...

  10. Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus

    2011-01-01

    The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential...... mode buck-based amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency domain behaviour of this converter and parameterize it to meet the design criteria...... in such configuration when applied for audio....

  11. A flexible dual-mode proximity sensor based on cooperative sensing for robot skin applications

    Science.gov (United States)

    Huang, Ying; Cai, Xia; Kan, Wenqing; Qiu, Shihua; Guo, Xiaohui; Liu, Caixia; Liu, Ping

    2017-08-01

    A flexible dual-mode proximity sensor has been designed and implemented, which is capable of combining capacitive-resistive detection in this paper. The capacitive type proximity sensor detecting is defined as mode-C, and the resistive type proximity sensor detecting is defined as mode-R. The characteristics of the proximity sensor are as follows: (1) the theoretical mode is developed which indicates that this proximity sensor can reflect proximity information accurately; (2) both sensing modes are vertically integrated into a sandwich-like chip with an 8 mm × 12 mm unit area. The thickness of a mode-R sensing material (graphene nanoplatelets) and mode-C dielectric (the mixture of carbon black and silicone rubber) is 1 mm and 2.5 mm, respectively; (3) for mode-R, the linearity of temperature-resistance curve can achieve 0.998 in the temperature range from 25°C to 65°C. And for mode-C, various materials can be successfully detected with fast response and high reversibility. Meanwhile, the study compensated the influence of object temperature to ensure mode-C properly works. A cooperative sensing test shows that R-C dual modes sense effectively which can enlarge the sensing distance compared with the single mode proximity sensor. The fabrication of this sensor is convenient, and the integrity of a flexible sandwich-like structure based on dual modes is beneficial to form arrays, which is suitable to be used in skin-like sensing applications.

  12. Performance-Based Adaptive Gradient Descent Optimal Coefficient Fuzzy Sliding Mode Methodology

    Directory of Open Access Journals (Sweden)

    Hossein Rezaie

    2012-10-01

    Full Text Available Design a nonlinear controller for second order nonlinear uncertain dynamical systems is the main challenge in this paper. This paper focuses on the design and analysis of a chattering free Mamdani’s fuzzy-based tuning gradient descent optimal error-based fuzzy sliding mode controller for highly nonlinear dynamic six degrees of freedom robot manipulator, in presence of uncertainties. Conversely, pure sliding mode controller is used in many applications; it has two important drawbacks namely; chattering phenomenon and nonlinear equivalent dynamic formulation in uncertain dynamic parameter. In order to solve the uncertain nonlinear dynamic parameters, implement easily and avoid mathematical model base controller, Mamdani’s performance/error-based fuzzy logic methodology with two inputs and one output and 49 rules is applied to pure sliding mode controller. Pure sliding mode controller and error-based fuzzy sliding mode controller have difficulty in handling unstructured model uncertainties. To solve this problem applied fuzzy-based tuning method to error-based fuzzy sliding mode controller for adjusting the sliding surface gain. Since the sliding surface gain is adjusted by gradient descent optimization method. Fuzzy-based tuning gradient descent optimal error-based fuzzy sliding mode controller is stable model-free controller which eliminates the chattering phenomenon without to use the boundary layer saturation function. Lyapunov stability is proved in fuzzy-based tuning gradient descent optimal fuzzy sliding mode controller based on switching (sign function. This controller has acceptable performance in presence of uncertainty (e.g., overshoot=0%, rise time=0.8 second, steady state error = 1e-9 and RMS error=1.8e-12.

  13. Structural Protein-based Flexible Whispering Gallery Mode Resonators

    CERN Document Server

    Yilmaz, Huzeyfe; Shreiner, Robert; Szwejkowski, Chester J; Jung, Huihun; Hopkins, Patrick; Ozdemir, Sahin Kaya; Yang, Lan; Demirel, Melik C

    2016-01-01

    Nature provides a set of solutions for photonic structures that are finely tuned, organically diverse and optically efficient. Exquisite knowledge of structure-property relationships in proteins aids in the design of materials with desired properties for building devices with novel functionalities, which are difficult to achieve or previously unattainable. Recent bio-inspired photonic platforms made from proteinaceous materials lay the groundwork for many functional device applications, such as electroluminescence in peptide nucleic acids1, multiphoton absorption in amyloid fibers2 and silk waveguides and inverse opals3-5. Here we report whispering-gallery-mode (WGM) microresonators fabricated entirely from semi-crystalline structural proteins (i.e., squid ring teeth, SRT, from Loligo vulgaris and its recombinant, and silk from Bombyx mori) with unconventional thermo-optic response. We present a striking example of how small modifications at the molecular level lead to structural changes and alter macroscopic...

  14. Electromagnetic controllable surfaces based on trapped-mode effect

    Directory of Open Access Journals (Sweden)

    V. Dmitriev

    2012-10-01

    Full Text Available In this paper we present some recent results of our theoretical investigations of electromagnetically controllable surfaces. These surfaces are designed on the basis of periodic arrays made of metallic inclusions of special form which are placed on a thin substrate of active material (magnetized ferrite or optically active semiconductor. The main peculiarity of the studied structures is their capability to support the trapped-mode resonance which is a result of the antiphase current oscillations in the elements of a periodic cell. Several effects, namely: tuning the position of passband and the linear and nonlinear (bistable transmission switching are considered when an external static magnetic field or optical excitation are applied. Our numerical calculations are fulfilled in both microwave and optical regions.

  15. Opto-VLSI-based tunable single-mode fiber laser.

    Science.gov (United States)

    Xiao, Feng; Alameh, Kamal; Lee, Tongtak

    2009-10-12

    A new tunable fiber ring laser structure employing an Opto-VLSI processor and an erbium-doped fiber amplifier (EDFA) is reported. The Opto-VLSI processor is able to dynamically select and couple a waveband from the gain spectrum of the EDFA into a fiber ring, leading to a narrow-linewidth high-quality tunable laser output. Experimental results demonstrate a tunable fiber laser of linewidth 0.05 nm and centre wavelength tuned over the C-band with a 0.05 nm step. The measured side mode suppression ratio (SMSR) is greater than 35 dB and the laser output power uniformity is better than 0.25 dB. The laser output is very stable at room temperature.

  16. Research on Chinese Agricultural Industrialization Based on SCP Mode

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Taking the SCP mode of industrial organization theory as the starting point,the paper analyzes Chinese agricultural market structure,market conduct and conduct performance and draws lessons from foreign experiences in developing agriculture.In the process of agricultural industrialization,Chinese agricultural development exists the problems of low intensive degree,low degree of differential products,surplus labor forces,low agricultural profit rate and low industrial contribution rate and farmers’ difficultly in adapting to market competition.The paper puts forward suggestions for addressing the problems,which include underpinning the cooperation of operation main bodies and developing rural cooperative organizations;promoting land transfer and clarifying land property;accelerating rural surplus labors transfer and abating trade barriers;increasing technology input and improving the contribution rate of technologies;improving circulation channels and intensifying agricultural competitiveness.

  17. Piezoelectric rotational mixer based on a first bending vibration mode.

    Science.gov (United States)

    Mashimo, Tomoaki

    2013-10-01

    We propose a miniature piezoelectric mixer that can rotate a liquid inside a hole of several millimeters diameter. The mixer has dimensions 14 × 14 × 10 mm with a through-hole (7 mm), and piezoelectric elements bonded to its four identical sides. When the first bending vibration mode of the mixer is excited by ac voltages, rotational flow of liquid is generated by the rotation of an acoustic field (acoustic streaming) in the through-hole. This technology is useful in automating mixing processes such as the mixing by hand of a few drops of blood in medical testing. In this paper, we verify the driving principle experimentally and examine the characteristics of a prototype mixer, including the induced flow velocity, under changes of the amplitude and frequency of the applied voltages. A plastic test tube, used to prevent contamination, is inserted to the through-hole, and the liquid inside the tube is mixed by rotation of the acoustic field.

  18. Development of a wearable exoskeleton rehabilitation system based on hybrid control mode

    Directory of Open Access Journals (Sweden)

    Yi Long

    2016-10-01

    Full Text Available Lower limb rehabilitation exoskeletons usually help patients walk based on fixed gait trajectories. However, it is not suitable for unilateral lower limb disorders. In this article, a hybrid training mode is proposed to be applied in rehabilitation for unilateral lower limb movement disorders. The hybrid training includes two modes, that is, the passive training mode and the active assist mode. At an early stage of the rehabilitation therapy, the passive training mode is utilized, in which microelectromechanical systems-based attitude and heading reference system is used to collect the gait trajectory of the healthy limb. The exoskeleton on the unhealthy limb will be driven to track the joint trajectory of the healthy limb. If the patient’s abilities recovered, the rehabilitation system can be switched to the active assist mode. Two force sensors are imbedded into the interface on the thigh to measure the interaction information in order to detect the patient’s initiative walking intention. In the active mode, the walking gait trajectory is modified and generated based on the gait trajectory of the healthy side via the attitude and heading reference system. In this article, a position close control loop is designed to drive the mechanical leg to help the unhealthy limb walk. Laboratory experiments are performed on a healthy human subject to illustrate the proposed approach. Experimental results show that the proposed method can be applied and extended in the passive and active rehabilitation mode for the unilateral lower limb disorders.

  19. Long-term frequency stabilization system for external cavity diode laser based on mode boundary detection.

    Science.gov (United States)

    Xu, Zhouxiang; Huang, Kaikai; Jiang, Yunfeng; Lu, Xuanhui

    2011-12-01

    We have realized a long-term frequency stabilization system for external cavity diode laser (ECDL) based on mode boundary detection method. In this system, the saturated absorption spectroscopy was used. The current and the grating of the ECDL were controlled by a computer-based feedback control system. By checking if there are mode boundaries in the spectrum, the control system determined how to adjust current to avoid mode hopping. This procedure was executed periodically to ensure the long-term stabilization of ECDL in the absence of mode hops. This diode laser system with non-antireflection coating had operated in the condition of long-term mode-hop-free stabilization for almost 400 h, which is a significant improvement of ECDL frequency stabilization system.

  20. Disaggregate Traffic Mode Choice Model Based on Combination of Revealed and Stated Preference Data

    Institute of Scientific and Technical Information of China (English)

    JIAO Pengpeng; LU Huapu; YANG Lang

    2006-01-01

    The conventional traffic demand forecasting methods based on revealed preference (RP) data are not able to predict the modal split. Passengers' stated intentions are indispensable for modal split forecasting and evaluation of new traffic modes. This paper analyzed the biases and errors included in stated preference data, put forward the new stochastic utility functions, and proposed an unbiased disaggregate model and its approximate model based on the combination of RP and stated preference (SP) data, with analysis of the parameter estimation algorithm. The model was also used to forecast rail transit passenger volumes to the Beijing Capital International Airport and the shift ratios from current traffic modes to rail transit. Experimental results show that the model can greatly increase forecasting accuracy of the modal split ratio of current traffic modes and can accurately forecast the shift ratios from current modes to the new mode.

  1. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul;

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  2. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  3. Mode-evolution-based polarization rotation and coupling between silicon and hybrid plasmonic waveguides

    Science.gov (United States)

    Kim, Sangsik; Qi, Minghao

    2015-12-01

    Hybrid plasmonic (HP) modes allow strong optical field confinement and simultaneously low propagation loss, offering a potentially compact and efficient platform for on-chip photonic applications. However, their implementation is hampered by the low coupling efficiency between dielectric guided modes and HP modes, caused by mode mismatch and polarization difference. In this work, we present a mode-evolution-based polarization rotation and coupling structure that adiabatically rotates the TE mode in a silicon waveguide and couples it to the HP mode in a strip silicon-dielectric-metal waveguide. Simulation shows that high coupling factors of 92%, 78%, 75%, and 73% are achievable using Ag, Au, Al, and Cu as the metal cap, respectively, at a conversion length of about 5 μm. For an extremely broad wavelength range of 1300-1800 nm, the coupling factor is >64% with a Ag metal cap, and the total back-reflection power, including all the mode reflections and backscattering, is below -40 dB, due to the adiabatic mode transition. Our device does not require high-resolution lithography and is tolerant to fabrication variations and imperfections. These attributes together make our device suitable for optical transport systems spanning all telecommunication bands.

  4. Optimum Position of Polarizer-Based Compensator for Enhanced Tolerance to Polarization Mode Dispersion

    Institute of Scientific and Technical Information of China (English)

    Daniele; Alzetta; Masayuki; Matsumoto

    2003-01-01

    We show through numerical simulation that the performance of two types of polarization-mode dispersion polarizer-based compensation techniques may be improved by optimizing the position of the compensator along the transmission line.

  5. Model-Based Resource and Mode Management for Lunar Surface Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project is aimed at developing a model based resource and mode management system for space robotics systems that will allow real time assessment of...

  6. Observer-based robust finite time H∞ sliding mode control for Markovian switching systems with mode-dependent time-varying delay and incomplete transition rate.

    Science.gov (United States)

    Gao, Lijun; Jiang, Xiaoxiao; Wang, Dandan

    2016-03-01

    This paper investigates the problem of robust finite time H∞ sliding mode control for a class of Markovian switching systems. The system is subjected to the mode-dependent time-varying delay, partly unknown transition rate and unmeasurable state. The main difficulty is that, a sliding mode surface cannot be designed based on the unknown transition rate and unmeasurable state directly. To overcome this obstacle, the set of modes is firstly divided into two subsets standing for known transition rate subset and unknown one, based on which a state observer is established. A component robust finite-time sliding mode controller is also designed to cope with the effect of partially unknown transition rate. It is illustrated that the reachability, finite-time stability, finite-time boundedness, finite-time H∞ state feedback stabilization of sliding mode dynamics can be ensured despite the unknown transition rate. Finally, the simulation results verify the effectiveness of robust finite time control problem.

  7. Automated aberration compensation in high numerical aperture systems for arbitrary laser modes (Conference Presentation)

    Science.gov (United States)

    Hering, Julian; Waller, Erik H.; von Freymann, Georg

    2017-02-01

    Since a large number of optical systems and devices are based on differently shaped focal intensity distributions (point-spread-functions, PSF), the PSF's quality is crucial for the application's performance. E.g., optical tweezers, optical potentials for trapping of ultracold atoms as well as stimulated-emission-depletion (STED) based microscopy and lithography rely on precisely controlled intensity distributions. However, especially in high numerical aperture (NA) systems, such complex laser modes are easily distorted by aberrations leading to performance losses. Although different approaches addressing phase retrieval algorithms have been recently presented[1-3], fast and automated aberration compensation for a broad variety of complex shaped PSFs in high NA systems is still missing. Here, we report on a Gerchberg-Saxton[4] based algorithm (GSA) for automated aberration correction of arbitrary PSFs, especially for high NA systems. Deviations between the desired target intensity distribution and the three-dimensionally (3D) scanned experimental focal intensity distribution are used to calculate a correction phase pattern. The target phase distribution plus the correction pattern are displayed on a phase-only spatial-light-modulator (SLM). Focused by a high NA objective, experimental 3D scans of several intensity distributions allow for characterization of the algorithms performance: aberrations are reliably identified and compensated within less than 10 iterations. References 1. B. M. Hanser, M. G. L. Gustafsson, D. A. Agard, and J. W. Sedat, "Phase-retrieved pupil functions in wide-field fluorescence microscopy," J. of Microscopy 216(1), 32-48 (2004). 2. A. Jesacher, A. Schwaighofer, S. Frhapter, C. Maurer, S. Bernet, and M. Ritsch-Marte, "Wavefront correction of spatial light modulators using an optical vortex image," Opt. Express 15(9), 5801-5808 (2007). 3. A. Jesacher and M. J. Booth, "Parallel direct laser writing in three dimensions with spatially dependent

  8. Performance-Based Adaptive Gradient Descent Optimal Coefficient Fuzzy Sliding Mode Methodology

    OpenAIRE

    Hossein Rezaie; Arman Jahed; Bamdad Boroomand; Farzin Piltan

    2012-01-01

    Design a nonlinear controller for second order nonlinear uncertain dynamical systems is the main challenge in this paper. This paper focuses on the design and analysis of a chattering free Mamdani’s fuzzy-based tuning gradient descent optimal error-based fuzzy sliding mode controller for highly nonlinear dynamic six degrees of freedom robot manipulator, in presence of uncertainties. Conversely, pure sliding mode controller is used in many applications; it has two important drawbacks namely; c...

  9. A Sliding Mode Control-based on a RBF Neural Network for Deburring Industry Robotic Systems

    OpenAIRE

    Yong Tao; Jiaqi Zheng; Yuanchang Lin

    2016-01-01

    A sliding mode control method based on radial basis function (RBF) neural network is proposed for the deburring of industry robotic systems. First, a dynamic model for deburring the robot system is established. Then, a conventional SMC scheme is introduced for the joint position tracking of robot manipulators. The RBF neural network based sliding mode control (RBFNN-SMC) has the ability to learn uncertain control actions. In the RBFNN-SMC scheme, the adaptive tuning algorithms for network par...

  10. Complete leaky mode coupling in dual-core photonic crystal fibre based on the coupled-mode theory

    Institute of Scientific and Technical Information of China (English)

    Yuan Jin-Hui; Yu Chong-Xiu; Sang Xin-Zhu; Zhang Jin-Long; Zhou Gui-Yao; Hou Lan-Tian

    2011-01-01

    This paper theoretically investigates the dependence of leaky mode coupling between inner core fundamental mode and outer core defect mode on phase and loss matching in pure silica dual-core photonic crystal fibres with the multi-pole method. The complete mode coupling can take place when both the phase and loss matching conditions are satisfied at the avoided anti-crossing wavelength. It shows the influences of cladding structure parameters including the diameters of cladding air holes d1, diameters of outer core holes d2 and hole to hole pitch A on the characteristics of leaky modes coupling. The coupled-mode theory is used to analyse the mode transition characteristics and the complete coupling can be clearly indicated by comparing the real and imaginary parts of propagation constant of the leaky modes.

  11. Local topological charge analysis of electromagnetic vortex beam based on empirical mode decomposition

    CERN Document Server

    Hui, Xiaonan; Zhang, Weite; Jin, Xiaofeng; Chi, Hao; Zhang, Xianmin

    2015-01-01

    The topological charge of an electromagnetic vortex beam depends on its wavefront helicity. For mixed vortex beams composed of several different coaxial vortices, the topological charge spectrum can be obtained by Fourier transform. However, the vortex beam is generally divergent and imperfect. It makes it significant to investigate the local topological charges, especially in radio frequency regime. Fourier transform based methods are restrained by the uncertainty principle and cannot achieve high angular resolution and mode resolution simultaneously. In this letter, an analysis method for local topological charges of vortex beams is presented based on the empirical mode decomposition (EMD). From EMD, the intrinsic mode functions (IMFs) can be obtained to construct the bases of the electromagnetic wave, and each local topological charge can be respectively defined. With this method the local value achieves both high resolution of azimuth angle and topological charge, meanwhile the amplitudes of each OAM mode...

  12. Stable Gait Generation of a Quasi-Passive Biped Walking Robot Based on Mode Decomposition

    Science.gov (United States)

    Matsumoto, Itaru

    A passive walker is a robot which can walk down a shallow slope without active control or energy input, being powered only by gravity. This paper proposes a control law that can stabilize the gait of a quasi-passive walker by manipulating torque at the hip joint. The motion of the quasi-passive walker is divided into two modes: one is a sinusoidal mode and the other a hyperbolic sinusoidal mode. The controller is designed with a servo system which forces the motion of the sinusoidal mode to track the reference input signal obtained from the phase-plane trajectory of the hyperbolic sinusoidal mode. The generated gait is quite natural, because the input of the servo system is made based on the system dynamics. The results of simulations have demonstrated the effectiveness of the proposed control law.

  13. New approach to Tolman's electronic parameter based on local vibrational modes.

    Science.gov (United States)

    Kalescky, Robert; Kraka, Elfi; Cremer, Dieter

    2014-01-06

    Tolman's electronic parameter (TEP) derived from the A1-symmetrical CO stretching frequency of nickel-phosphine-tricarbonyl complexes, R3PNi(CO)3, is brought to a new, improved level by replacing normal with local vibrational frequencies. CO normal vibrational frequencies are always flawed by mode-mode coupling especially with metal-carbon stretching modes, which leads to coupling frequencies as large as 100 cm(-1) and can become even larger when the transition metal and the number of ligands is changed. Local TEP (LTEP) values, being based on local CO stretching force constants rather than normal mode frequencies, no longer suffer from mode coupling and mass effects. For 42 nickel complexes of the type LNi(CO)3, it is shown that LTEP values provide a different ordering of ligand electronic effects as previously suggested by TEP and CEP values. The general applicability of the LTEP concept is demonstrated.

  14. A fiber micro-vibration sensor based on single-mode fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Shenglai Zhen; Renzhu Liu; Benli Yu; Jing Zhang; Baogang Han

    2009-01-01

    A new micro-vibration sensor based on single-mode fiber ring laser is put forward. The Mach-Zehnder interferometric (MZI) detection technique is presented for interrogating laser frequency shift due to the measurand (piezoelectric transducer (PZT) is used to simulate the micro-vibration) induced laser cavity strain from both single- and multi-mode lasers. In the experiment, compared with multi-mode laser sensors, the single-mode laser sensor is proved to be a sensor with high resolution. When the PZT is driven by the analog signal (0.03 rad near 2 kHz), the signal-to-noise ratio (SNR) of output signal from the single-mode laser sensor is close to 55 dB and the sensitivity of the sensor is about 5 x 10-5 rad/Hz1/2.

  15. DVI Film Flow Instability Based on the Normal Mode Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Young; Euh, Dong Jin [Handong Global Univ., Pohang (Korea, Republic of)

    2013-10-15

    In the present paper, as the first step of nonlinear studies, the appearance of the third order spatial differentiation of the film thickness in the wave propagation equation is to be derived. The two-fluid model in the adiabatic condition is employed and normal mode analysis. Interfacial pressure forces between steam and water need to be modeled for this purpose. n the present study, we developed a theoretical basis to study nonlinear wave phenomena on the DVI film flow which highly affect the DVI penetration and liquid droplets entrainment out. We set the hyperbolicity breaking condition by providing the interfacial pressure difference considering the curvature of the reactor vessel. The interfacial pressure difference could generate nonlinear wave such as the horseshoe wave which has been believed as a main source of film break up to produce huge amount of droplets to be entrained out. As a safety injection method, the direct vessel injection has been intensively developed in Korea and employed in the APR1400. The developing efforts were made from the determination of the number, location and size of DVI nozzles to the experimental demonstrations. Experimental facilities with various scales have shown its complicated phenomena due to highly nonlinear interaction between the steam and injected water flow. The injected DVI water forms a film type flow but very unstable due to the unsteady energetic steam flow which find the exits around the shell of the downcomer of the reactor vessel. This steam and liquid film interaction leads to the instability on the surface of the film flow and the waves are highly nonlinear to form undercutting, roll over, and finally droplet releasing. The entrained droplets causes a difficulty in the analysis to estimate the water penetrated into the reactor core to cool the nuclear fuels heated up. Unfortunately, these instabilities on the interface of the DVI liquid film have not been studied appropriately and the conservative

  16. Cavity modes with optical orbital angular momentum in a metamaterial ring based on transformation optics.

    Science.gov (United States)

    Wu, H W; Wang, F; Dong, Y Q; Shu, F Z; Zhang, K; Peng, R W; Xiong, X; Wang, Mu

    2015-12-14

    In this work, we theoretically study the cavity modes with transverse orbital angular momentum in metamaterial ring based on transformation optics. The metamaterial ring is designed to transform the straight trajectory of light into the circulating one by enlarging the azimuthal angle, effectively presenting the modes with transverse orbital angular momentum. The simulation results confirm the theoretical predictions, which state that the transverse orbital angular momentum of the mode not only depends on the frequency of the incident light, but also depends on the transformation scale of the azimuthal angle. Because energy dissipation inevitably reduces the field amplitude of the modes, the confined electromagnetic energy and the quality factor of the modes inside the ring are also studied in order to evaluate the stability of those cavity modes. The results show that the metamaterial ring can effectively confine light with a high quality factor and maintain steady modes with the orbital angular momentum, even if the dimension of the ring is much smaller than the wavelength of the incident light. This technique for exploiting the modes with optical transverse orbital angular momentum may provides a unique platform for applications related to micromanipulation.

  17. Tamm-plasmon and surface-plasmon hybrid-mode based refractometry in photonic bandgap structures.

    Science.gov (United States)

    Das, Ritwick; Srivastava, Triranjita; Jha, Rajan

    2014-02-15

    The transverse magnetic (TM) polarized hybrid modes formed as a consequence of coupling between Tamm plasmon polariton (TM-TPP) mode and surface plasmon polariton (SPP) mode exhibit interesting dispersive features for realizing a highly sensitive and accurate surface plasmon resonance (SPR) sensor. We found that the TM-TPP modes, formed at the interface of distributed Bragg reflector and metal, are strongly dispersive as compared to SPP modes at optical frequencies. This causes an appreciably narrow interaction bandwidth between TM-TPP and SPP modes, which leads to highly accurate sensing. In addition, appropriate tailoring of dispersion characteristics of TM-TPP as well as SPP modes could ensure high sensitivity of a novel SPR platform. By suitably designing the Au/TiO₂/SiO₂-based geometry, we propose a TM-TPP/SPP hybrid-mode sensor and achieve a sensitivity ≥900  nm/RIU with high detection accuracy (≥30  μm⁻¹) for analyte refractive indices varying between 1.330 and 1.345 in 600-700 nm wavelength range. The possibility to achieve desired dispersive behavior in any spectral band makes the sensing configuration an extremely attractive candidate to design sensors depending on the availability of optical sources.

  18. Numerical analysis of a photonic crystal fiber based on two polarized modes for biosensing applications

    Institute of Scientific and Technical Information of China (English)

    Qin Wei; Li Shu-Guang; Xue Jian-Rong; Xin Xü-Jun; Zhang Lei

    2013-01-01

    This paper presents a theoretical study on a photonic crystal fiber plasmonic refractive index biosensor.The proposed photonic crystal fiber sensor introduces the concept of simultaneous detection with the linearly polarized and radially polarized modes because the sensing performance of the sensor based on both modes is relatively high,which will be useful for selecting the modes to make the detection accurately.The sharp single resonant peaks of the linearly polarized mode and radially polarized mode,are stronger and more sensitive to the variation of analyte refractive index than that of any other polarized mode in this kind of photonic crystal fiber.For linearly polarized mode and radially polarized mode,the maximum sensitivities of 10448.5 nm per refractive index unit and 8230.7 nm per refractive index unit can be obtained,as well as 949.8 and 791.4 for figure of merits in the sensing range of 1.33-1.45,respectively.Compared with the conventional Au-metalized surface plasmon resonance sensors,our device is better and can be applied as a biosensor.

  19. Knowledge Innovation Mode Based on New Product Development Procedure

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi

    2011-01-01

    Knowledge classification based on new product development procedure The new product development procedure requires that each stage has necessary activity and output result,generally files,in fact these output results are coded product knowledge produced in each stage,also including product knowledge and process knowledge without coding,for instance the knowledge and experiences of project management,etc.

  20. Near-Field Nanolasers based on Nonradiating Anapole Modes

    KAUST Repository

    Gongora, J. S. Totero

    2016-05-31

    By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern.

  1. Demand and supply-based operating modes--a framework for analyzing health care service production.

    Science.gov (United States)

    Lillrank, Paul; Groop, P Johan; Malmström, Tomi J

    2010-12-01

    The structure of organizations that provide services should reflect the possibilities of and constraints on production that arise from the market segments they serve. Organizational segmentation in health care is based on urgency and severity as well as disease type, bodily function, principal method, or population subgroup. The result is conflicting priorities, goals, and performance metrics. A managerial perspective is needed to identify activities with similar requirements for integration, coordination, and control. The arguments in this article apply new reasoning to the previous literature. The method used in this article to classify health care provision distinguishes different types of health problems that share generic constraints of production. The analysis leads to seven different demand-supply combinations, each with its own operational logic. These are labeled demand and supply-based operating modes (DSO modes), and constitute the managerial building blocks of health care organizations. The modes are Prevention, Emergency, One visit, Project, Elective, Cure, and Care. As analytical categories the DSO modes can be used to understand current problems. Several operating modes in one unit create managerial problems of conflicting priorities, goals, and performance metrics. The DSO modes are constructed as managerially homogeneous categories or care platforms responding to general types of demand, and supply constraints. The DSO modes bring methods of industrial management to bear on efforts to improve health care. © 2010 Milbank Memorial Fund. Published by Wiley Periodicals Inc.

  2. Study of node and mass sensitivity of resonant mode based cantilevers with concentrated mass loading

    Directory of Open Access Journals (Sweden)

    Kewei Zhang

    2015-12-01

    Full Text Available Resonant-mode based cantilevers are an important type of acoustic wave based mass-sensing devices. In this work, the governing vibration equation of a bi-layer resonant-mode based cantilever attached with concentrated mass is established by using a modal analysis method. The effects of resonance modes and mass loading conditions on nodes and mass sensitivity of the cantilever were theoretically studied. The results suggested that the node did not shift when concentrated mass was loaded on a specific position. Mass sensitivity of the cantilever was linearly proportional to the square of the point displacement at the mass loading position for all the resonance modes. For the first resonance mode, when mass loading position xc satisfied 0 < xc < ∼ 0.3l (l is the cantilever beam length and 0 represents the rigid end, mass sensitivity decreased as the mass increasing while the opposite trend was obtained when mass loading satisfied ∼0.3l ≤ xc ≤ l. Mass sensitivity did not change when concentrated mass was loaded at the rigid end. This work can provide scientific guidance to optimize the mass sensitivity of a resonant-mode based cantilever.

  3. Sliding Mode Control Approach for Electrically Controllable Clutch of AMT Based on the Feedback Linearization

    Institute of Scientific and Technical Information of China (English)

    程东升; 张建武; 叶晓峰; 黄维纲

    2003-01-01

    A sliding mode control approach based on the feedback linearization is proposed for the electrically controllable clutch of AMT vehicles. The nonlinear dynamic model for the hydraulic actuator associated with clutch is established. By means of the exact feedback linearization procedure of differential geometry, an equivalent, fully controllable and linear model is derived via a homomorphic transformation for the AMT clutch system.Furthermore, a sliding mode control is introduced to improve robustness. The tracking tests are performed using the sliding mode control on a Santana LX passenger car, and the experimental results prove that this nonlinear controller is of fine robustness and high degree of tracking accuracy.

  4. Tensor Product Model Transformation Based Adaptive Integral-Sliding Mode Controller: Equivalent Control Method

    Directory of Open Access Journals (Sweden)

    Guoliang Zhao

    2013-01-01

    Full Text Available This paper proposes new methodologies for the design of adaptive integral-sliding mode control. A tensor product model transformation based adaptive integral-sliding mode control law with respect to uncertainties and perturbations is studied, while upper bounds on the perturbations and uncertainties are assumed to be unknown. The advantage of proposed controllers consists in having a dynamical adaptive control gain to establish a sliding mode right at the beginning of the process. Gain dynamics ensure a reasonable adaptive gain with respect to the uncertainties. Finally, efficacy of the proposed controller is verified by simulations on an uncertain nonlinear system model.

  5. Tensor product model transformation based adaptive integral-sliding mode controller: equivalent control method.

    Science.gov (United States)

    Zhao, Guoliang; Sun, Kaibiao; Li, Hongxing

    2013-01-01

    This paper proposes new methodologies for the design of adaptive integral-sliding mode control. A tensor product model transformation based adaptive integral-sliding mode control law with respect to uncertainties and perturbations is studied, while upper bounds on the perturbations and uncertainties are assumed to be unknown. The advantage of proposed controllers consists in having a dynamical adaptive control gain to establish a sliding mode right at the beginning of the process. Gain dynamics ensure a reasonable adaptive gain with respect to the uncertainties. Finally, efficacy of the proposed controller is verified by simulations on an uncertain nonlinear system model.

  6. Investigation into Mass Loading Sensitivity of Sezawa Wave Mode-Based Surface Acoustic Wave Sensors

    OpenAIRE

    N. Ramakrishnan; Parthiban, R.; Sawal Hamid Md Ali; Md. Shabiul Islam; Ajay Achath Mohanan

    2013-01-01

    In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film...

  7. Analysis of current-bidirectional buck-boost based switch-mode audio amplifier

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus

    2011-01-01

    The following studdy was carried out in order to assses quantitatively the performannce of the buck--boost converter whhen used as swiitch-mode audio amplifier. It comprises of, to beggin with, the de limitation of design criteria bassed on the state of-the-art solution, which is based...... in a differential mode buckbased amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency-wise behaviour of this converter and parameterize it to meet the design criteria...... in such configuration when applied for audio....

  8. Finite time control for MIMO nonlinear system based on higher-order sliding mode.

    Science.gov (United States)

    Liu, Xiangjie; Han, Yaozhen

    2014-11-01

    Considering a class of MIMO uncertain nonlinear system, a novel finite time stable control algorithm is proposed based on higher-order sliding mode concept. The higher-order sliding mode control problem of MIMO nonlinear system is firstly transformed into finite time stability problem of multivariable system. Then continuous control law, which can guarantee finite time stabilization of nominal integral chain system, is employed. The second-order sliding mode is used to overcome the system uncertainties. High frequency chattering phenomenon of sliding mode is greatly weakened, and the arbitrarily fast convergence is reached. The finite time stability is proved based on the quadratic form Lyapunov function. Examples concerning the triple integral chain system with uncertainty and the hovercraft trajectory tracking are simulated respectively to verify the effectiveness and the robustness of the proposed algorithm.

  9. Terminal sliding mode fuzzy control based on multiple sliding surfaces for nonlinear ship autopilot systems

    Science.gov (United States)

    Yuan, Lei; Wu, Han-Song

    2010-12-01

    A terminal sliding mode fuzzy control based on multiple sliding surfaces was proposed for ship course tracking steering, which takes account of rudder characteristics and parameter uncertainty. In order to solve the problem, the controller was designed by employing the universal approximation property of fuzzy logic system, the advantage of Nussbaum function, and using multiple sliding mode control algorithm based on the recursive technique. In the last step of designing, a nonsingular terminal sliding mode was utilized to drive the last state of the system to converge in a finite period of time, and high-order sliding mode control law was designed to eliminate the chattering and make the system robust. The simulation results showed that the controller designed here could track a desired course fast and accurately. It also exhibited strong robustness peculiarly to system, and had better adaptive ability than traditional PID control algorithms.

  10. Second Order Sliding Mode-Based Output Feedback Tracking Control for Uncertain Robot Manipulators

    OpenAIRE

    Van, Mien; Hee-Jun Kang; Young-Soo Suh

    2013-01-01

    In this paper, a robust output feedback tracking control scheme for motion control of uncertain robot manipulators without joint velocity measurement based on a second-order sliding mode (SOSM) observer is presented. Two second‐order sliding mode observers with finite time convergence are developed for velocity estimation and uncertainty identification, respectively. The first SOSM observer is used to estimate the state vector in finite time without filtration. However, for uncertainty identi...

  11. A Novel Fuzzy Logic Based Adaptive Supertwisting Sliding Mode Control Algorithm for Dynamic Uncertain Systems

    OpenAIRE

    Abdul Kareem; Mohammad Fazle Azeem

    2012-01-01

    This paper presents a novel fuzzy logic based Adaptive Super-twisting Sliding Mode Controller for the control of dynamic uncertain systems. The proposed controller combines the advantages of Second order Sliding Mode Control, Fuzzy Logic Control and Adaptive Control. The reaching conditions, stability and robustness of the system with the proposed controller are guaranteed. In addition, the proposed controller is well suited for simple design and implementation. The effectiveness ...

  12. Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber.

    Science.gov (United States)

    Tian, Zhaobing; Yam, Scott S-H; Loock, Hans-Peter

    2008-05-15

    A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by approximately 500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease of fabrication offers a low-cost alternative to current sensing applications.

  13. Mode Selective Actuator-Sensor System for Lamb Wave-Based Structural Health Monitoring

    OpenAIRE

    Schmidt, Daniel; Wierach, Peter; Sinapius, Michael

    2014-01-01

    International audience; Structural Health Monitoring (SHM) based on Lamb waves, a type of ultrasonic guided waves, is a promising method for in-service inspection of composite structures. In this study mode selective actuators and sensors are investigated to excite a particular Lamb wave mode in composite plates. The actuator and sensor exhibit an interdigital transducer design. In order to describe the complex displacement fields of

  14. Impairments due to Burst-Mode Transmission in a Raman-based Long Reach PON Link

    DEFF Research Database (Denmark)

    Kjær, Rasmus; Tafur Monroy, Idelfonso; Oxenløwe, Leif Katsuo;

    2007-01-01

    A recently proposed passive-optical-network (PON) link based on distributed Raman amplification is tested with disturbing burst-mode traffic. The resulting impairments are quantified through penalty measurements on a single surviving data channel as a function of the disturbing channel power. When...... that the highly linear PON link is a promising candidate for long-reach feeder links in future, high-capacity PON systems with burst-mode traffic....

  15. Low-cost sliding mode control of WECS based on DFIG with stability analysis

    OpenAIRE

    DJOUDI, ABDELHAK; CHEKIREB, Hachemi; BERKOUK, EL MADJID; Bacha, Seddik

    2015-01-01

    The aim of this work is to developing sliding mode control of active and reactive stator powers produced by a wind energy conversion system (WECS), based on doubly fed induction generator (DFIG). A flux estimation model and rotor current sensor are no longer required. The controller is developed from the DFIG nonlinear-coupled model. Moreover, the global stability and the DFIG states' boundedness when our low-cost sliding mode control is applied are established analytically. It is reveal...

  16. A Compound Fuzzy Disturbance Observer Based on Sliding Modes and Its Application on Flight Simulator

    OpenAIRE

    Yunjie Wu; Youmin Liu; Dapeng Tian

    2013-01-01

    A compound fuzzy disturbance observer based on sliding modes is developed, and its application on flight simulator is presented. Fuzzy disturbance observer (FDO) is an effective method in nonlinear control. However, traditional FDO is confined to monitor dynamic disturbance, and the frequency bandwidth of the system is restricted. Sliding mode control (SMC) compensates the high-frequency component of disturbance while it is limited by the chattering phenomenon. The proposed method uses the sl...

  17. Chaos Control in Memristor-based Oscillators Using Intelligent Sliding Mode Control

    OpenAIRE

    Amir Hossein Abolmasoumi; Somayeh Khosravinejad

    2014-01-01

    In this paper, Intelligent Sliding Mode Control of chaos in a memristor- based Chua’s oscillator is investigated. In order to gain stabilization and tracking of a sinusoidal input, an appropriate sliding surface is proposed and sliding gain is tuned. Also, to avoid the chattering phenomenon in traditional sliding mode controller, and to reduce the hitting time of the controlled system, an especial genetic algorithm optimization method is suggested. By defining a new objective func...

  18. N-Annulated Perylene as a Donor in Cyclopentadithiophene Based Sensitizers: The Effect of Linking Mode

    KAUST Repository

    Luo, Jie

    2015-11-24

    Two types of cyclopentadithiophene dyes with different linking modes with an N-annulated perylene (NP) donor were designed and synthesized. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells and an efficiency up to 7.8% could be obtained for peri-NP linked CPD-1. The effect of the linking mode on the material properties and device performance was discussed.

  19. Chaos control in delayed chaotic systems via sliding mode based delayed feedback

    Energy Technology Data Exchange (ETDEWEB)

    Vasegh, Nastaran [Faculty of Electrical Engineering, K.N. Toosi University of Technology, Seyed Khandan Bridge, Shariati St. 16314, P.O. Box 16315-1355, Tehran (Iran, Islamic Republic of)], E-mail: vasegh@eetd.kntu.ac.ir; Sedigh, Ali Khaki [Faculty of Electrical Engineering, K.N. Toosi University of Technology, Seyed Khandan Bridge, Shariati St. 16314, P.O. Box 16315-1355, Tehran (Iran, Islamic Republic of)

    2009-04-15

    This paper investigates chaos control for scalar delayed chaotic systems using sliding mode control strategy. Sliding surface design is based on delayed feedback controller. It is shown that the proposed controller can achieve stability for an arbitrary unstable fixed point (UPF) or unstable periodic orbit (UPO) with arbitrary period. The chaotic system used in this study to illustrate the theoretical concepts is the well known Mackey-Glass model. Simulation results show the effectiveness of the designed nonlinear sliding mode controller.

  20. Research and Practice of the Construction Mode of the Practical Training Base for Agriculture and Forestry

    Institute of Scientific and Technical Information of China (English)

    Guiying; LIU; Junjie; WANG; Xuebin; LI; Jian; ZHANG

    2013-01-01

    In response to bottlenecks and dilemmas faced by institutions for agricultural and forestry practical training base construction, and based on Agriculture practical training base of Langfang Polytechnic Institute, this article illustrates the effective exploration and practice of the mode and ways for the construction of the practical training base,which provides some useful experience for the construction of the training base in agricultural and forestry institutions.

  1. Sensorless sliding mode torque control of an IPMSM drive based on active flux concept

    Directory of Open Access Journals (Sweden)

    A.A. Hassan

    2012-03-01

    Full Text Available This paper investigates a novel direct torque control of a sensorless interior permanent magnet synchronous motor based on a sliding mode technique. The speed and position of the interior permanent magnet synchronous motor are estimated online based on active flux concept. To overcome the large ripple content associated with the direct torque, a torque/flux sliding mode controller has been employed. Two integral surface functions are used to construct the sliding mode controller. The command voltage is estimated from the torque and flux errors based on the two switching functions. The idea of the total sliding mode is used to eliminate the problem of reaching phase stability. The space vector modulation is combined with the sliding mode controller to ensure minimum torque and flux ripples and provides high resolution voltage control. The proposed scheme has the advantages of simple implementation, and does not require an external signal injection. In addition, it combines the merits of the direct torque control, sliding mode controller, and space vector modulation besides to the sensorless control. Simulation works are carried out to demonstrate the ability of the proposed scheme at different operating conditions. The results confirm the high performance of the proposed scheme at standstill, low and high speeds including load disturbance and parameters variation.

  2. Circular Economy Development Mode Based on System Theory

    Institute of Scientific and Technical Information of China (English)

    Xiao Huamao; Wang Fengqi

    2007-01-01

    The paper tries to explore circular economy from the viewpoint of the system theory.Circular economy is a kind of complicated economic acdvity,and it is a wholly new ecotype economy pmposed by Western countries after they had summed up many experiences and lessons from traditional economy.It is an entirety and has many layers.It keeps an open and dynamic balance.Because the system theory is the theoretical foundation of circular economy,we should systemically analyze and study circular economy from the macroscopic view,correctly grasp its operational laws,improve its service functions,and realize human beings's ustainable development.The paper introduces the content and general characteristics of the system theory and the idea of circular economy.Then it analyzes circular economy based on the systemtheory.The paper concludes that the intonation of circular economy and the system theory can promote the functions of circular economy.

  3. A nonlinear multi-mode wideband piezoelectric vibration-based energy harvester using compliant orthoplanar spring

    Energy Technology Data Exchange (ETDEWEB)

    Dhote, Sharvari, E-mail: sharvari.dhote@mail.utoronto.ca; Zu, Jean; Zhu, Yang [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario M5S-3G8 (Canada)

    2015-04-20

    In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.

  4. Energy transmission modes based on Tabu search and particle swarm hybrid optimization algorithm

    Institute of Scientific and Technical Information of China (English)

    LI xiang; CUI Ji-feng; QI Jian-xun; YANG Shang-dong

    2007-01-01

    In China, economic centers are far from energy storage bases, so it is significant to select a proper energy transferring mode to improve the efficiency of energy usage, To solve this problem, an optimal allocation model based on energy transfer mode was proposed after objective function for optimizing energy using efficiency Was established, and then, a new Tabu search and power transmission was gained.Based on the above discussion, some proposals were put forward for optimal allocation of energy transfer modes in China. By comparing other three traditional methodsthat are based on regional price differences. freight rates and annual cost witll the proposed method, the result indicates that the economic efficiency of the energy transfer Can be enhanced by 3.14%, 5.78% and 6.01%, respectively.

  5. Improvement of mechanical performance for vibratory microgyroscope based on sense mode closed-loop control

    Science.gov (United States)

    Xiao, Dingbang; Su, Jianbin; Chen, Zhihua; Hou, Zhanqiang; Wang, Xinghua; Wu, Xuezhong

    2013-04-01

    In order to improve its structural sensitivity, a vibratory microgyroscope is commonly sealed in high vacuum to increase the drive mode quality factor. The sense mode quality factor of the microgyroscope will also increase simultaneously after vacuum sealing, which will lead to a long decay time of free response and even self-oscillation of the sense mode. As a result, the mechanical performance of the microgyroscope will be seriously degraded. In order to solve this problem, a closed-loop control technique is presented to adjust and optimize the sense mode quality factor. A velocity feedback loop was designed to increase the electric damping of the sense mode vibration. A circuit was fabricated based on this technique, and experimental results indicate that the sense mode quality factor of the microgyroscope was adjusted from 8052 to 428. The decay time of the sense mode free response was shortened from 3 to 0.5 s, and the vibration-rejecting ability of the microgyroscope was improved obviously without sensitivity degradation.

  6. Robust Sliding Mode Control of Cucumber Picking Robot Based on the Upper Bound Estimation

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2015-02-01

    Full Text Available In this study, a robust sliding mode control based on upper bound estimation was applied in position trajectory control of the fruit harvesting robot. It decomposes the manipulator dynamics equation into a constant unknown vector parameter and a known dynamic nonlinear (called the regression vector. This study based on regression design new sliding mode control law. The algorithm ensures the stability of the closed-loop system upper based on unknown upper bound estimation parameters. It shows from robustness analysis that when the system has the time-varying uncertainty, the closed loop system can still be stabilized.

  7. A-mode ultrasound-based registration in computer-aided surgery of the skull.

    Science.gov (United States)

    Amstutz, Christoph; Caversaccio, Marco; Kowal, Jens; Bächler, Richard; Nolte, Lutz-Peter; Häusler, Rudolf; Styner, Martin

    2003-12-01

    To evaluate the integration and accuracy of A (amplitude)-mode ultrasound-based surface matching for noninvasive registration of the head into a frameless computer-aided surgery system for otorhinology and skull base surgery. Experimental study and case series. Academic medical center. Twelve patients underwent anterior and paranasal skull base surgery with the routine use of a computer-aided surgery system. A computer-aided surgery system, based on an optoelectronic localizer, was used to track the skull and the surgical tools, including the A-mode ultrasound probe. The A-mode probe was a 10-MHz immersion transducer. An acoustic lens attached to the transducer focused the ultrasonic beam to a depth of 1 to 10 mm. Accuracy tests were performed for the ultrasound setup. Different surface point distributions were evaluated with respect to matching accuracy on a human cadaver skull specimen equipped with fiducial markers. The matching comparison was based on the fiducial registration error. For the clinical evaluation, the laboratory setup was transferred to the operating room. Noninvasive registration of the skull by using A-mode ultrasound in computer-aided surgery (practical and clinical measurements). The accuracy tests on the human skull specimen revealed that the mean +/- SD fiducial registration error was 1.00 +/- 0.19 mm in the best series for A-mode ultrasound surface matchings and was robust with respect to different sets of surface points. The mean +/- SD root mean square error from the 12 A-mode ultrasound matchings in the patient study was 0.49 +/- 0.20 mm. A-mode ultrasound surface matching can be used as a noninvasive and accurate registration procedure in computer-aided surgery of the head.

  8. C-band fundamental/first-order mode converter based on multimode interference coupler on InP substrate

    Science.gov (United States)

    Limeng, Zhang; Dan, Lu; Zhaosong, Li; Biwei, Pan; Lingjuan, Zhao

    2016-12-01

    The design, fabrication and characterization of a fundamental/first-order mode converter based on multimode interference coupler on InP substrate were reported. Detailed optimization of the device parameters were investigated using 3D beam propagation method. In the experiments, the fabricated mode converter realized mode conversion from the fundamental mode to the first-order mode in the wavelength range of 1530-1565 nm with excess loss less than 3 dB. Moreover, LP01 and LP11 fiber modes were successfully excited from a few-mode fiber by using the device. This InP-based mode converter can be a possible candidate for integrated transceivers for future mode-division multiplexing system. Project supported by the National Basic Research Program of China (No. 2014CB340102) and in part by the National Natural Science Foundation of China (Nos. 61274045, 61335009).

  9. Data-based matched-mode source localization for a moving source.

    Science.gov (United States)

    Yang, T C

    2014-03-01

    A data-based matched-mode source localization method is proposed in this paper for a moving source, using mode wavenumbers and depth functions estimated directly from the data, without requiring any environmental acoustic information and assuming any propagation model. The method is in theory free of the environmental mismatch problem because the mode replicas are estimated from the same data used to localize the source. Besides the estimation error due to the approximations made in deriving the data-based algorithms, the method has some inherent drawbacks: (1) It uses a smaller number of modes than theoretically possible because some modes are not resolved in the measurements, and (2) the depth search is limited to the depth covered by the receivers. Using simulated data, it is found that the performance degradation due to the afore-mentioned approximation/limitation is marginal compared with the original matched-mode source localization method. The proposed method has a potential to estimate the source range and depth for real data and be free of the environmental mismatch problem, noting that certain aspects of the (estimation) algorithms have previously been tested against data. The key issues are discussed in this paper.

  10. ERROR COUNTER-BASED NEGATIVE ACKNOWLEDGEMENT MODE IN CCSDS FILE DELIVERY PROTOCOL

    Institute of Scientific and Technical Information of China (English)

    Xiao Shijie; Yang Mingchuan; Guo Qing

    2011-01-01

    Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in terrestrial communications.Accordingly,the Consultative Committee for Space Data Systems (CCSDS) developed CCSDS File Delivery Protocol (CFDP),which sets standards of efficient file delivery service capable of transferring files to and from mass memory located in the space segment.In CFDP,four optional acknowledge modes are supported to make the communication more reliable.In this paper,we gave a general introduction of typical communication process in CFDP and analysis of its four Negative Acknowledgement (NAK) modes on the respect of file delivery delay and times of retransmission.We found out that despite the shortest file delivery delay,immediate NAK mode suffers from the problem that frequent retransmission may probably lead to network congestion.Thus,we proposed a new mode,the error counter-based NAK mode.By simulation of the case focused on the link between a deep space probe on Mars and a terrestrial station on Earth,we concluded that error counter-based NAK mode has successfully reduced the retransmission times at negligible cost of certain amount of file delivery delay.

  11. The Study of Operation Modes and Control Strategies of a Multidirectional MC for Battery Based System

    Directory of Open Access Journals (Sweden)

    Saman Toosi

    2015-01-01

    Full Text Available To enhance the performance of stand-alone battery based system and to achieve the continuous power transmission, the behavior of multidirectional matrix converter (MDMC has been analyzed in different operation modes. A systematic method interfacing a renewable source, a storage battery, and a load is proposed for a stand-alone battery based power system (SABBPS to utilize the MDMC as PWM converter, inverter, or PWM converter and inverter in different operation modes. In this study, the Extended Direct Duty Pulse Width Modulation (EDDPWM technique has been applied to control the power flow path between the renewable source, load, and the battery. Corresponding to generator voltage, input frequency, and loads demands, several operating states and control strategies are possible. Therefore, the boundaries and distribution of operation modes are discussed and illustrated to improve the system performance. The mathematical equation of the EDDPWM under different operation modes has been derived to achieve the maximum voltage ratio in each mode. The theoretical and modulation concepts presented have been verified in simulation using MATLAB and experimental testing. Moreover, the THD, ripple, and power flow direction have been analyzed for output current to investigate the behavior of system in each operation mode.

  12. Neuro-Sliding-Mode Control of Flexible-Link Manipulators Based on Singularly Perturbed Model

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; YANG Tangwen; SUN Zengqi

    2009-01-01

    A neuro-sliding-mode control (NSMC) strategy was developed to handle the complex nonlinear dynamics and model uncertainties of flexible-link manipulators. A composite controller was designed based on a singularly perturbed model of flexible-link manipulators when the rigid motion and flexible motion are decoupled. The NSMC is employed to control the slow subsystem to track a desired trajectory with a traditional sliding mode controller to stabilize the fast subsystem which represents the link vibrations. A stability analysis of the flexible modes is also given. Simulations confirm that the NSMC performs better than the tra-ditional sliding-mode control for controlling flexible-link manipulators. The control strategy not only gives good tracking performance for the joint angle, but also effectively suppresses endpoint vibrations. The simulations also show that the control strategy has a strong self-adaptive ability for controlling manipulators with different parameters.

  13. A Compound Fuzzy Disturbance Observer Based on Sliding Modes and Its Application on Flight Simulator

    Directory of Open Access Journals (Sweden)

    Yunjie Wu

    2013-01-01

    Full Text Available A compound fuzzy disturbance observer based on sliding modes is developed, and its application on flight simulator is presented. Fuzzy disturbance observer (FDO is an effective method in nonlinear control. However, traditional FDO is confined to monitor dynamic disturbance, and the frequency bandwidth of the system is restricted. Sliding mode control (SMC compensates the high-frequency component of disturbance while it is limited by the chattering phenomenon. The proposed method uses the sliding mode technique to deal with the uncompensated dynamic equivalent disturbance. The switching gain of sliding mode control designed according to the error of disturbance estimation is a small value. Therefore, the proposal also helps to decrease the chattering. The validity of the proposal method is confirmed by experiments on flight simulator.

  14. Robust Sliding Mode Control of Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    Guangping Zhuo

    2016-12-01

    Full Text Available The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. The application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches.

  15. Simulation-based comparisons of four apparel cell production modes of one clothing production line

    Directory of Open Access Journals (Sweden)

    Guoqiang Pan

    2014-10-01

    Full Text Available Purpose: This research, by using the SIMIO simulation platform, provides a quantitative and comparative analysis of how the efficiency of four different cell production modes is affected. It is hoped that the outcomes will be of some help for garment factories to optimize their production lines. Design/methodology/approach: The SIMIO simulation platform was employed in the research and comparisons were made of the simulation test results about the four different production modes. Findings: The operation mode, number of operators, and number of buffer areas are key factors affecting the production line efficiency, and need to be reasonably set to achieve the highest efficiency. Originality/value: As most research literature so far is qualitative, this research provided a simulation-based quantitative analysis of the production efficiency under different cell production modes.

  16. A dual working mode mobile robot system based on visual guiding and visual servoing

    Institute of Scientific and Technical Information of China (English)

    Peng Yizhun; Yuan Kui; Zou Wei; Hu Huosheng

    2007-01-01

    A dual operational modes mobile robot system based on visual guiding and visual servo control is presented.This system consists of a mobile robot with a two-axis manipulator and a tele-operation station.In the visual guiding mode,for the robot works in an open loop visual servo control mode,the manipulating burden of the operator is reduced largely.In the visual servo mode the robot can locate the position of the target assigned by the operator and pick it up by its manipulator.With the help of the operator,the difficult problems of finding and handling a target in a complicated environment by the robot Can be solved easily.

  17. A robo-pigeon based on an innovative multi-mode telestimulation system.

    Science.gov (United States)

    Yang, Junqing; Huai, Ruituo; Wang, Hui; Lv, Changzhi; Su, Xuecheng

    2015-01-01

    In this paper, we describe a new multi-mode telestimulation system for brain-microstimulation for the navigation of a robo-pigeon, a new type of bio-robot based on Brain-Computer Interface (BCI) techniques. The multi-mode telestimulation system overcomes neuron adaptation that was a key shortcoming of the previous single-mode stimulation by the use of non-steady TTL biphasic pulses accomplished by randomly alternating pulse modes. To improve efficiency, a new behavior model ("virtual fear") is proposed and applied to the robo-pigeon. Unlike the previous "virtual reward" model, the "virtual fear" behavior model does not require special training. The performance and effectiveness of the system to alleviate the adaptation of neurons was verified by a robo-pigeon navigation test, simultaneously confirming the practicality of the "virtual fear" behavioral model.

  18. Electromagnetic-Power-based Characteristic Mode Theory for Perfect Electric Conductors

    CERN Document Server

    Lian, Renzun

    2016-01-01

    In this paper, an ElectroMagnetic-Power-based Characteristic Mode Theory (CMT) for PEC systems (PEC-EMP-CMT) is built. The PEC-EMP-CMT is valid for the PEC systems which are surrounded by any electromagnetic environment, and it can construct the complex characteristic currents and non-radiative Characteristic Modes (CMs). In this paper, some traditional concepts, such as the system input impedance and modal input impedance etc., are redefined; the traditional characteristic quantity, Modal Significance (MS), is generalized; a series of new power-based CM sets are introduced. It is proven in this paper that various power-based CM sets of a certain objective PEC structure are independent of the external environment and excitation; the non-radiative space constituted by all non-radiative modes is identical to the interior resonance space constituted by all interior resonant modes of closed PEC structures, and the non-radiative CMs constitute a basis of the space. Based on above these, the normal Eigen-Mode Theor...

  19. Sliding mode control of photoelectric tracking platform based on the inverse system method

    Directory of Open Access Journals (Sweden)

    Yao Zong Chen

    2016-01-01

    Full Text Available In order to improve the photoelectric tracking platform tracking performance, an integral sliding mode control strategy based on inverse system decoupling method is proposed. The electromechanical dynamic model is established based on multi-body system theory and Newton-Euler method. The coupled multi-input multi-output (MIMO nonlinear system is transformed into two pseudo-linear single-input single-output (SISO subsystems based on the inverse system method. An integral sliding mode control scheme is designed for the decoupled pseudo-linear system. In order to eliminate system chattering phenomenon caused by traditional sign function in sliding-mode controller, the sign function is replaced by the Sigmoid function. Simulation results show that the proposed decoupling method and the control strategy can restrain the influences of internal coupling and disturbance effectively, and has better robustness and higher tracking accuracy.

  20. Analysis and Synthesis of Memory-Based Fuzzy Sliding Mode Controllers.

    Science.gov (United States)

    Zhang, Jinhui; Lin, Yujuan; Feng, Gang

    2015-12-01

    This paper addresses the sliding mode control problem for a class of Takagi-Sugeno fuzzy systems with matched uncertainties. Different from the conventional memoryless sliding surface, a memory-based sliding surface is proposed which consists of not only the current state but also the delayed state. Both robust and adaptive fuzzy sliding mode controllers are designed based on the proposed memory-based sliding surface. It is shown that the sliding surface can be reached and the closed-loop control system is asymptotically stable. Furthermore, to reduce the chattering, some continuous sliding mode controllers are also presented. Finally, the ball and beam system is used to illustrate the advantages and effectiveness of the proposed approaches. It can be seen that, with the proposed control approaches, not only can the stability be guaranteed, but also its transient performance can be improved significantly.

  1. Efficient and spurious-free integral-equation-based optical waveguide mode solver.

    Science.gov (United States)

    Hochman, Amit; Leviatan, Yehuda

    2007-10-29

    Modal analysis of waveguides and resonators by integra-lequation formulations can be hindered by the existence of spurious solutions. In this paper, spurious solutions are shown to be eliminated by introduction of a Rayleigh-quotient based matrix singularity measure. Once the spurious solutions are eliminated, the true modes may be determined efficiently and reliably, even in the presence of degeneracy, by an adaptive search algorithm. Analysis examples that demonstrate the efficacy of the method include an elliptical dielectric waveguide, two unequal touching dielectric cylinders, a plasmonic waveguide, and a realistic micro-structured optical fiber. A freely downloadable version of an optical waveguide mode solver based on this article is available.

  2. Distributed delay-line interferometer based on a Bragg grating in transmission mode

    CERN Document Server

    Preciado, Miguel A; Shu, Xuewen; Sugden, Kate

    2016-01-01

    A novel approach for a delay line interferometer (DLI) based purely on forward Bragg scattering is proposed. We have numerically and experimentally demonstrated that a Bragg grating can deliver the functionality of a DLI in its transmission mode along a single common interfering optical path, instead of the conventional DLI implementation with two interfering optical paths. As a proof of concept, a fiber Bragg grating has been designed and fabricated, showing the desired functionality in the transmission mode of the Bragg grating. The proposed "Bragg-DLI" approach is applicable to any kind of Bragg grating technology, such as volume Bragg gratings, dielectric mirrors, silicon photonics, and other optical waveguide based Bragg structures.

  3. Identifying Different Transportation Modes from Trajectory Data Using Tree-Based Ensemble Classifiers

    Directory of Open Access Journals (Sweden)

    Zhibin Xiao

    2017-02-01

    Full Text Available Recognition of transportation modes can be used in different applications including human behavior research, transport management and traffic control. Previous work on transportation mode recognition has often relied on using multiple sensors or matching Geographic Information System (GIS information, which is not possible in many cases. In this paper, an approach based on ensemble learning is proposed to infer hybrid transportation modes using only Global Position System (GPS data. First, in order to distinguish between different transportation modes, we used a statistical method to generate global features and extract several local features from sub-trajectories after trajectory segmentation, before these features were combined in the classification stage. Second, to obtain a better performance, we used tree-based ensemble models (Random Forest, Gradient Boosting Decision Tree, and XGBoost instead of traditional methods (K-Nearest Neighbor, Decision Tree, and Support Vector Machines to classify the different transportation modes. The experiment results on the later have shown the efficacy of our proposed approach. Among them, the XGBoost model produced the best performance with a classification accuracy of 90.77% obtained on the GEOLIFE dataset, and we used a tree-based ensemble method to ensure accurate feature selection to reduce the model complexity.

  4. Investigation into Mass Loading Sensitivity of Sezawa Wave Mode-Based Surface Acoustic Wave Sensors

    Directory of Open Access Journals (Sweden)

    N. Ramakrishnan

    2013-02-01

    Full Text Available In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW device is investigated through finite element method (FEM simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

  5. Investigation into mass loading sensitivity of sezawa wave mode-based surface acoustic wave sensors.

    Science.gov (United States)

    Mohanan, Ajay Achath; Islam, Md Shabiul; Ali, Sawal Hamid; Parthiban, R; Ramakrishnan, N

    2013-02-06

    In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher) than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

  6. Research on the cultivation path of smart home-based care service mode in Internet+ vision

    Directory of Open Access Journals (Sweden)

    Peng Qingchao

    2016-01-01

    Full Text Available Home-based care for the aged is an effective method to solve the problem of caring the aged in China. This thesis analyzes some problems existing in the development of current home-based care service for the aged in our country and the positive effects brought by Internet+ in home-based care service. It proposes a new service mode of care for the aged--Internet+ home-based care service, and explains the establishment of this system and the responsibilities of the participants. Also, it explores the path to realize the establishment of Internet+ home-based care service mode so as to promote the healthy development of home-based care service in China.

  7. Projective synchronization of nonidentical fractional-order neural networks based on sliding mode controller.

    Science.gov (United States)

    Ding, Zhixia; Shen, Yi

    2016-04-01

    This paper investigates global projective synchronization of nonidentical fractional-order neural networks (FNNs) based on sliding mode control technique. We firstly construct a fractional-order integral sliding surface. Then, according to the sliding mode control theory, we design a sliding mode controller to guarantee the occurrence of the sliding motion. Based on fractional Lyapunov direct methods, system trajectories are driven to the proposed sliding surface and remain on it evermore, and some novel criteria are obtained to realize global projective synchronization of nonidentical FNNs. As the special cases, some sufficient conditions are given to ensure projective synchronization of identical FNNs, complete synchronization of nonidentical FNNs and anti-synchronization of nonidentical FNNs. Finally, one numerical example is given to demonstrate the effectiveness of the obtained results.

  8. Co-evolution of strain design methods based on flux balance and elementary mode analysis

    DEFF Research Database (Denmark)

    Machado, Daniel; Herrgard, Markus

    2015-01-01

    optimization to couple cellular growth with the production of a target product. This initiated the development of a family of strain design methods based on the concept of flux balance analysis. Another family of strain design methods, based on the concept of elementary mode analysis, has also been growing......More than a decade ago, the first genome-scale metabolic models for two of the most relevant microbes for biotechnology applications, Escherichia coli and Saccaromyces cerevisiae, were published. Shortly after followed the publication of OptKnock, the first strain design method using bilevel....... Although the computation of elementary modes is hindered by computational complexity, recent breakthroughs have allowed applying elementary mode analysis at the genome scale. Here we review and compare strain design methods and look back at the last 10 years of in silico strain design with constraint...

  9. Instantaneous Gradient Based Dual Mode Feed-Forward Neural Network Blind Equalization Algorithm

    Directory of Open Access Journals (Sweden)

    Ying Xiao

    2013-01-01

    Full Text Available To further improve the performance of feed-forward neural network blind equalization based on Constant Modulus Algorithm (CMA cost function, an instantaneous gradient based dual mode between Modified Constant Modulus Algorithm (MCMA and Decision Directed (DD algorithm was proposed. The neural network weights change quantity of the adjacent iterative process is defined as instantaneous gradient. After the network converges, the weights of neural network to achieve a stable energy state and the instantaneous gradient would be zero. Therefore dual mode algorithm can be realized by criterion which set according to the instantaneous gradient. Computer simulation results show that the dual mode feed-forward neural network blind equalization algorithm proposed in this study improves the convergence rate and convergence precision effectively, at the same time, has good restart and tracking ability under channel burst interference condition.

  10. Quantum dot based detections of propagating plasmonic modes excited by bowtie antennas

    Science.gov (United States)

    Wen, Jing; Wang, Kang; Feng, Hui; Lv, Yating; Chen, Jiannong; Zhang, Dawei

    2017-03-01

    Propagating plasmonic modes excited by bowtie apertures based on emissions from a layer of CdSe/ZnS quantum dots are experimentally detected. The mode distributions with a cladding of 20 nm thick Al2O3 film in between the silver and the quantum dot layers are more homogenous compared to the uncoated structure. The variation discipline of the effective indexes and the decay lengths of the plasmonic modes are discussed for various refractive indexes and thicknesses of the cladding. The three dimensional field distributions of the structure are simulated and the plasmonic fields are only excited in and around the cladding layer on top of the silver film. Such quantum dots based detection methods are promising tools for simultaneous imaging of near field optical distributions in integrated plasmonic nano-circuits.

  11. Backstepping design of missile guidance and control based on adaptive fuzzy sliding mode control

    Institute of Scientific and Technical Information of China (English)

    Ran Maopeng; Wang Qing; Hou Delong; Dong Chaoyang

    2014-01-01

    This paper presents an integrated missile guidance and control law based on adaptive fuzzy sliding mode control. The integrated model is formulated as a block-strict-feedback nonlinear system, in which modeling errors, unmodeled nonlinearities, target maneuvers, etc. are viewed as unknown uncertainties. The adaptive nonlinear control law is designed based on backstepping and sliding mode control techniques. An adaptive fuzzy system is adopted to approximate the coupling nonlinear functions of the system, and for the uncertainties, we utilize an online-adaptive control law to estimate the unknown parameters. The stability analysis of the closed-loop system is also conducted. Simulation results show that, with the application of the adaptive fuzzy sliding mode control, small miss distances and smooth missile trajectories are achieved, and the system is robust against system uncertainties and external disturbances.

  12. Optimization for operating modes based on simulation of seasonal underground thermal energy storage

    Institute of Scientific and Technical Information of China (English)

    Jun ZHAO; Yan CHEN; Xinguo LI

    2008-01-01

    A simulation was performed, which concerned the feasibility of seasonal underground thermal energy storage (UTES) in Tianjin, China. The investigated sys-tem consisted of 8 boreholes. In summer, residual solar thermal energy was emitted into the soil surrounding the borehole heat exchangers through which the stored energy was extracted in winter with a ground coupled heat pump (GCHP) to provide a proper heating temperature. A simulation study was performed to study the influence of system operation modes on thermal recovery based on the experimental data of a GCHP system, local met-eorological conditions and soil properties in Tianjin. The results indicate a thermal recovery ratio of less than 67% and different temperature distributions under three modes. Finally, an operation mode was suggested based on both lower loss and better thermal recovery in the UTES.

  13. Design of Tank Velocity Based on Multi-Mode Natural Frequencies for Suppression of Sloshing

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Taegwon; Kim, Dongjoo [Kumoh Nat’l Institute of Technology, Gumi (Korea, Republic of)

    2017-05-15

    Suppression of sloshing is essential to achieve fast transportation and stable maneuvering of tanks partially filled with liquid. In this study, numerical simulations are performed to investigate the effects of the acceleration magnitude and the acceleration duration of triangular velocity profiles on sloshing when a rectangular tank moves horizontally. We previously reported, based on only the first natural mode, that sloshing is significantly suppressed when the acceleration duration equals the first natural period of sloshing. On the other hand, the present CFD simulations find the best acceleration duration for minimum sloshing and explains the results considering higher modes as well as the first mode. We also perform the analysis using an equivalent model based on masses and springs, and evaluate its accuracy by comparing it with the CFD simulation results.

  14. Non-model-based damage identification of plates using principal, mean and Gaussian curvature mode shapes

    Science.gov (United States)

    Xu, Y. F.; Zhu, W. D.; Smith, S. A.

    2017-07-01

    Mode shapes have been extensively used to identify structural damage. This paper presents a new non-model-based method that uses principal, mean and Gaussian curvature mode shapes (CMSs) to identify damage in plates; the method is applicable to mode shapes associated with low and high elastic modes on dense and coarse measurement grids and robust against measurement noise. A multi-scale discrete differential-geometry scheme is proposed to calculate principal, mean and Gaussian CMSs associated with a mode shape of a plate, which can alleviate adverse effects of measurement noise on calculating the CMSs. Principal, mean and Gaussian CMSs of a damaged plate and those of an undamaged one are used to yield four curvature damage indices (CDIs), including Maximum-CDIs, Minimum-CDIs, Mean-CDIs and Gaussian-CDIs. Damage can be identified near regions with consistently higher values of the CDIs. It is shown that a mode shape of an undamaged plate can be well approximated using a polynomial of a properly determined order that fits a mode shape of a damaged one, provided that the undamaged plate has a smooth geometry and is made of material that has no stiffness and mass discontinuities. Fitting and convergence indices are introduced to quantify the level of approximation of a mode shape from a polynomial fit to that of a damaged plate and to determine the proper order of the polynomial fit, respectively. A weight function is applied to the proposed CDIs to alleviate adverse effects of measurement noise on the CDIs and manifest existence of damage in the CDIs. A mode shape of an aluminum plate with damage in the form of a machined thickness reduction area was measured to experimentally investigate effectiveness of the proposed CDIs in damage identification; the damage on the plate was successfully identified. The experimental damage identification results were numerically verified by applying the proposed method to the mode shape associated with the same mode as that of the

  15. GPU-Based Optimal Control Techniques for Resistive Wall Mode Control on DIII-D

    Science.gov (United States)

    Clement, M.; Navratil, G. A.; Hanson, J. M.; Strait, E. J.

    2014-10-01

    The DIII-D tokamak can excite strong, locked or nearly locked kink modes whose rotation frequencies do not evolve quickly and are slow compared to their growth rates. To control such modes, DIII-D plans to implement a Graphical Processing Unit (GPU) based feedback control system in a low-latency architecture based on system developed on the HBT-EP tokamak. Up to 128 local magnetic sensors will be used to extrapolate the state of the rotating kink mode, which will be used by the feedback algorithm to calculate the required currents for the internal and/or external control coils. Offline techniques for resolving the mode structure of the resistive wall mode (RWM) will be presented and compared along with the proposed GPU implementation scheme and potential real-time estimation algorithms for RWM feedback. Work supported by the US Department of Energy under DE-FG02-07ER54917, DE-FG02-04ER54761, and DE-FC02-04ER54698.

  16. Transportation Mode Detection Based on Permutation Entropy and Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2015-01-01

    Full Text Available With the increasing prevalence of GPS devices and mobile phones, transportation mode detection based on GPS data has been a hot topic in GPS trajectory data analysis. Transportation modes such as walking, driving, bus, and taxi denote an important characteristic of the mobile user. Longitude, latitude, speed, acceleration, and direction are usually used as features in transportation mode detection. In this paper, first, we explore the possibility of using Permutation Entropy (PE of speed, a measure of complexity and uncertainty of GPS trajectory segment, as a feature for transportation mode detection. Second, we employ Extreme Learning Machine (ELM to distinguish GPS trajectory segments of different transportation. Finally, to evaluate the performance of the proposed method, we make experiments on GeoLife dataset. Experiments results show that we can get more than 50% accuracy when only using PE as a feature to characterize trajectory sequence. PE can indeed be effectively used to detect transportation mode from GPS trajectory. The proposed method has much better accuracy and faster running time than the methods based on the other features and SVM classifier.

  17. Mode Switching for the Multi-Antenna Broadcast Channel Based on Delay and Channel Quantization

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2009-01-01

    Full Text Available Imperfect channel state information degrades the performance of multiple-input multiple-output (MIMO communications; its effects on single-user (SU and multiuser (MU MIMO transmissions are quite different. In particular, MU-MIMO suffers from residual interuser interference due to imperfect channel state information while SU-MIMO only suffers from a power loss. This paper compares the throughput loss of both SU and MU-MIMO in the broadcast channel due to delay and channel quantization. Accurate closed-form approximations are derived for achievable rates for both SU and MU-MIMO. It is shown that SU-MIMO is relatively robust to delayed and quantized channel information, while MU-MIMO with zero-forcing precoding loses its spatial multiplexing gain with a fixed delay or fixed codebook size. Based on derived achievable rates, a mode switching algorithm is proposed, which switches between SU and MU-MIMO modes to improve the spectral efficiency based on average signal-to-noise ratio (SNR, normalized Doppler frequency, and the channel quantization codebook size. The operating regions for SU and MU modes with different delays and codebook sizes are determined, and they can be used to select the preferred mode. It is shown that the MU mode is active only when the normalized Doppler frequency is very small, and the codebook size is large.

  18. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen

    2016-09-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  19. Current Mode Full-Wave Rectifier Based on a Single MZC-CDTA

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2013-01-01

    Full Text Available This paper presents a current mode full-wave rectifier based on single modified Z copy current difference transconductance amplifier (MZC-CDTA and two switches. The circuit is simple and is suitable for IC implementation. The functionality of the circuit is verified with SPICE simulation using 0.35 μm TSMC CMOS technology parameters.

  20. PCB Slot Based Transformers to Avoid Common-Mode Resonances in Connected Arrays of Dipoles

    NARCIS (Netherlands)

    Cavallo, D.; Neto, A.; Gerini, G.

    2010-01-01

    The scanning performances of connected arrays are degraded by the excitation of common-mode resonances that are compatible with balanced feeding lines. Here, a strategy to avoid these resonances is outlined. The strategy involves feeding the dipoles via printed circuit board (PCB) based transformers

  1. An imaging algorithm based on keystone transform for one-stationary bistatic SAR of spotlight mode

    Science.gov (United States)

    Qiu, Xiaolan; Behner, Florian; Reuter, Simon; Nies, Holger; Loffeld, Otmar; Huang, Lijia; Hu, Donghui; Ding, Chibiao

    2012-12-01

    This article proposes an imaging algorithm based on Keystone Transform for bistatic SAR with a stationary receiver. It can efficiently be applied to high-resolution spotlight mode, and can directly be process the bistatic SAR data which have been ranged compressed by the synchronization reference pulses. Both simulation and experimental results validate the good performance of this algorithm.

  2. Low noise pixel detectors based on gated geiger mode avalanche photodiodes

    OpenAIRE

    Vilella Figueras, Eva; Comerma Montells, Albert; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel

    2011-01-01

    The gated operation is proposed as an effective method to reduce the noise in pixel detectors based on Geiger mode avalanche photodiodes. A prototype with the sensor and the front-end electronics monolithically integrated has been fabricated with a conventional HV-CMOS process. Experimental results demonstrate the increase of the dynamic range of the sensor by applying this technique.

  3. Innovative mode of action based in vitro assays for detection of marine neurotoxins

    NARCIS (Netherlands)

    Nicolas, J.A.Y.

    2015-01-01

    Innovative mode of action based in vitro assays for detection of marine neurotoxins J. Nicolas, P.J.M. Hendriksen, T.F.H. Bovee, I.M.C.M. Rietjens Marine biotoxins are naturally occurring compounds produced by particular phytoplankton species. These toxins often accumulate in seafood and thereby

  4. Does mode mixing matter in EMD-based highlight volume methods for hydrocarbon detection? Experimental evidence

    Science.gov (United States)

    Xue, Ya-juan; Cao, Jun-xing; Du, Hao-kun; Zhang, Gu-lan; Yao, Yao

    2016-09-01

    Empirical mode decomposition (EMD)-based spectral decomposition methods have been successfully used for hydrocarbon detection. However, mode mixing that occurs during the sifting process of EMD causes the 'true' intrinsic mode function (IMF) to be extracted incorrectly and blurs the physical meaning of the IMF. We address the issue of how the mode mixing influences the EMD-based methods for hydrocarbon detection by introducing mode-mixing elimination methods, specifically ensemble EMD (EEMD) and complete ensemble EMD (CEEMD)-based highlight volumes, as feasible tools that can identify the peak amplitude above average volume and the peak frequency volume. Three schemes, that is, using all IMFs, selected IMFs or weighted IMFs, are employed in the EMD-, EEMD- and CEEMD-based highlight volume methods. When these methods were applied to seismic data from a tight sandstone gas field in Central Sichuan, China, the results demonstrated that the amplitude anomaly in the peak amplitude above average volume captured by EMD, EEMD and CEEMD combined with Hilbert transforms, whether using all IMFs, selected IMFs or weighted IMFs, are almost identical to each other. However, clear distinctions can be found in the peak frequency volume when comparing results generated using all IMFs, selected IMFs, or weighted IMFs. If all IMFs are used, the influence of mode mixing on the peak frequency volume is not readily discernable. However, using selected IMFs or a weighted IMFs' scheme affects the peak frequency in relation to the reservoir thickness in the EMD-based method. Significant improvement in the peak frequency volume can be achieved in EEMD-based highlight volumes using selected IMFs. However, if the weighted IMFs' scheme is adopted (i.e., if the undesired IMFs are included with reduced weights rather than excluded from the analysis entirely), the CEEMD-based peak frequency volume provides a more accurate reservoir thickness estimate compared with the other two methods. This

  5. Sliding Mode Control of PMSG Wind Turbine Based on Enhanced Exponential Reaching Law

    DEFF Research Database (Denmark)

    Mozayan, Seyed Mehdi; Saad, Maarouf; Vahedi, Hani

    2016-01-01

    This paper proposes a Sliding Mode Control (SMC) based scheme for a variable speed, direct-driven Wind Energy Conversion Systems (WECS) equipped with Permanent Magnet Synchronous Generator (PMSG) connected to the grid. In this work, diode rectifier, boost converter, Neutral Point Clamped (NPC...... great performance in complicated nonlinear systems control such as WECS. The proposed control strategy modifies Reaching Law (RL) of sliding mode technique to reduce chattering issue and to improve THD property compared to conventional reaching law SMC. The effectiveness of the proposed control strategy...

  6. Study on the Roles of a Teacher in College English Teaching Mode Based on the Internet

    Institute of Scientific and Technical Information of China (English)

    康燕茹

    2013-01-01

    With the rapid development of modern technology and all-round reform in national college English teaching, Inter⁃net-Based teaching mode has become a new trend of college English teaching. Therefore, in the new teaching mode, the teacher should turn an inculcator into an instructor, facilitator and participant in teaching;a passive user of textbook into a dominant and modeler of courses; a planner of teaching specific tasks into an organizer of teaching process, a helper and shepherd of learning knowledge.

  7. Effective amplifier noise for an optical receiver based on linear mode avalanche photodiodes

    Science.gov (United States)

    Chen, C.-C.

    1989-01-01

    The rms noise charge induced by the amplifier for an optical receiver based on the linear-mode avalanche photodiode (APD) was analyzed. It is shown that for an amplifier with a 1-pF capacitor and a noise temperature of 100 K, the rms noise charge due to the amplifier is about 300. Since the noise charge must be small compared to the signal gain, APD gains on the order of 1000 will be required to operate the receiver in the linear mode.

  8. Study on VMI Inventory Control Mode based on the Third-Party Logistics

    Directory of Open Access Journals (Sweden)

    Haoxiong Yang

    2014-02-01

    Full Text Available Adding the third party logistics enterprises between the suppliers and the retailers is a kind of the development of VMI mode, in this mode; inventory pressure is transferred to the third party logistics enterprise. In view of this situation, the VMI inventory control model which treats total inventory control costs as the objective function is built based on from four dimensions: the inventory holding costs, the fixed delivery costs, replenishment costs and customer waiting costs. After solving the model and sensitivity analyzing related parameters, it can be inferred that related parameters in the VMI model of the introduction of the third party logistics have effects on inventory control costs.

  9. A novel sensor of potassium ions based on mode-filtered light detection

    Institute of Scientific and Technical Information of China (English)

    Xiao Hong Zhao; Li Ping Yang; Suo Zhu Wu; Wen Ping Cheng; Shao Min Shuang; Chuan Dong

    2010-01-01

    A novel potassium ions sensor based on mode-filtered light detection was reported.The analyzer was consisting of an optical fiber immobilized with a dye of bromocresol green and a fused-silica capillary.It was found that mode-filtered light intensity decreased with the concentration of potassium ions and a linear detection range of 0.25-20 mmol/L(R2 = 0.9977)was obtained with a detection limit of 9 × 10-5 mol/L as well as fast response,good reproducibility and reversibility in the working concentration range.

  10. ECG baseline wander correction based on mean-median filter and empirical mode decomposition.

    Science.gov (United States)

    Xin, Yi; Chen, Yu; Hao, Wei Tuo

    2014-01-01

    A novel approach of ECG baseline wander correction based on mean-median filter and empirical mode decomposition is presented in this paper. The low frequency parts of the original signals were removed by the mean median filter in a nonlinear way to obtain the baseline wander estimation, then its series of IMFs were sifted by t-test after empirical mode decomposition. The proposed method, tested by the ECG signals in MIT-BIH Arrhythmia database and European ST_T database, is more effective compared with other baseline wander removal methods.

  11. Photonic Crystal Waveguide Intersection Based on Self-Imaging of Multi-Mode Interference

    Institute of Scientific and Technical Information of China (English)

    DING Wei-Qiang; TANG Dong-Hua; CHEN Li-Xue; ZHAO Yuan; Liu Yan

    2007-01-01

    @@ A new mechanism of intersection formed by two line defect photonic crystal (PC) waveguides are numerically investigated using the finite-difference time-domain method. The results show that the normalized crosstalk is smaller than 10-4; the reflection is smaller than 10-3, and the transmission is larger than 0.999. The authors analyse the physical origins and find that a modified self-imaging process in the intersected multi-mode region is the main reason of the excellent performance. This kind of multi-mode interference based intersection may find potential applications in PC optical circuits.

  12. Compact all-optical switches based on photon-induced suppression of mode interference

    Institute of Scientific and Technical Information of China (English)

    Longzhi Li; Yi Tang; Jianyi Yang; Minghua Wang; Xiaoqing Jiang

    2006-01-01

    @@ An optically activated optical switch based on suppression of mode interference (SMI) is presented. The imaging properties of multi-mode interference (MMI) section in the switch with Y-branch can be modified by a controlling light injection. The switch was simulated by finite difference beam propagation method(FD-BPM) and fabricated on GaAIAs/GaAs epitaxial materials. At the wavelength of 1.31 μm, the primary experiment showed an extinction ratio of about 8 dB with controlling light power density of 73.5W/mm2.

  13. Sliding mode output feedback control based on tracking error observer with disturbance estimator.

    Science.gov (United States)

    Xiao, Lingfei; Zhu, Yue

    2014-07-01

    For a class of systems who suffers from disturbances, an original output feedback sliding mode control method is presented based on a novel tracking error observer with disturbance estimator. The mathematical models of the systems are not required to be with high accuracy, and the disturbances can be vanishing or nonvanishing, while the bounds of disturbances are unknown. By constructing a differential sliding surface and employing reaching law approach, a sliding mode controller is obtained. On the basis of an extended disturbance estimator, a creative tracking error observer is produced. By using the observation of tracking error and the estimation of disturbance, the sliding mode controller is implementable. It is proved that the disturbance estimation error and tracking observation error are bounded, the sliding surface is reachable and the closed-loop system is robustly stable. The simulations on a servomotor positioning system and a five-degree-of-freedom active magnetic bearings system verify the effect of the proposed method.

  14. A Novel Control Approach Based on Second Order Sliding Modes & Its Application to Hydraulic Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.

    2013-01-01

    Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics...... accuracy to be reached. In this paper a novel control approach based on second order sliding modes utilizing the idea of the power rate reaching law is introduced. Dependent on parameters the proposed controller may preserve the main features of sliding controls, while at the same time avoiding control....... This may be avoided by application of smoothing functions imposing boundary layers on the control constraint, or by carrying out the design in relation to the control derivative. However, such boundary layers introduces additional design parameters and actuator dynamics may not allow the desired control...

  15. Robustness-tracking control based on sliding mode and H∞ theory for linear servo system

    Institute of Scientific and Technical Information of China (English)

    TIAN Yan-feng; GUO Qing-ding

    2005-01-01

    A robustness-tracking control scheme based on combining H∞ robust control and sliding mode control is proposed for a direct drive AC permanent-magnet linear motor servo system to solve the conflict between tracking and robustness of the linear servo system. The sliding mode tracking controller is designed to ensure the system has a fast tracking characteristic to the command, and the H∞ robustness controller suppresses the disturbances well within the close loop( including the load and the end effect force of linear motor etc. ) and effectively minimizes the chattering of sliding mode control which influences the steady state performance of the system. Simulation results show that this control scheme enhances the track-command-ability and the robustness of the linear servo system, and in addition, it has a strong robustness to parameter variations and resistance disturbances.

  16. Discussion on the teaching mode of higher vocational nursing specialty based on CDIO model

    Directory of Open Access Journals (Sweden)

    Xiu-fang CAI

    2013-11-01

    Full Text Available Discussion on the teaching mode of higher vocational nursing specialty based on CDIO model is the core of this study. CDIO is the latest achievement in the reform of the international higher education of engineering and has been thrived since 2000. There are some inevitable problems when domestic universities introduced and innovated the CDIO mode. Therefore the CDIO model is a bold attempt for the institutions of higher education, especially higher vocational college teachers. The CDIO mode drives teachers to reflect on the existed teaching philosophy, and therefore enables them to change teaching methods in the teaching process and improve their teaching capacity tremendously. Meanwhile, it also encourages students to learn automatically and cultivate their comprehensive abilities such as professional capability, development capability, interpersonal skills, innovation ability, etc.

  17. Trading strategy based on dynamic mode decomposition: Tested in Chinese stock market

    Science.gov (United States)

    Cui, Ling-xiao; Long, Wen

    2016-11-01

    Dynamic mode decomposition (DMD) is an effective method to capture the intrinsic dynamical modes of complex system. In this work, we adopt DMD method to discover the evolutionary patterns in stock market and apply it to Chinese A-share stock market. We design two strategies based on DMD algorithm. The strategy which considers only timing problem can make reliable profits in a choppy market with no prominent trend while fails to beat the benchmark moving-average strategy in bull market. After considering the spatial information from spatial-temporal coherent structure of DMD modes, we improved the trading strategy remarkably. Then the DMD strategies profitability is quantitatively evaluated by performing SPA test to correct the data-snooping effect. The results further prove that DMD algorithm can model the market patterns well in sideways market.

  18. Oscillation mode analysis considering the interaction between a DFIG-based wind turbine and the grid

    Science.gov (United States)

    Wu, Wangping; Xie, Da; Lu, Yupu; Zhao, Zuyi; Yu, Songtao

    2017-01-01

    Sub-synchronous interactions between wind farms and transmission networks with series compensation have drawn great attention. As most large wind farms in Europe and Asia employ doubly fed induction generator turbines, there has recently been a growing interest in studying this phenomenon. To study the stability of wind turbine with doubly fed induction generator after a small disturbance, a complete small signal system is built in this paper. By using eigenvalue and participation factor analysis, the relation between the modes and state variables can be discovered. Thereafter, the oscillation modes are classified into electrical resonance, sub-synchronous resonance, sub-synchronous oscillation, sub-synchronous control interaction, and low frequency oscillation. To verify the oscillation frequency of each oscillation mode, time-domain simulation based on MATLAB/Simulink is presented. The simulation results justify the effectiveness of the small-signal models.

  19. Multisensor Fault Identification Scheme Based on Decentralized Sliding Mode Observers Applied to Reconfigurable Manipulators

    Directory of Open Access Journals (Sweden)

    Bo Zhao

    2013-01-01

    Full Text Available This paper concerns with a fault identification scheme in a class of nonlinear interconnected systems. The decentralized sliding mode observer is recruited for the investigation of position sensor fault or velocity sensor fault. First, a decentralized neural network controller is proposed for the system under fault-free state. The diffeomorphism theory is utilized to construct a nonlinear transformation for subsystem structure. A simple filter is implemented to convert the sensor fault into pseudo-actuator fault scenario. The decentralized sliding mode observer is then presented for multisensor fault identification of reconfigurable manipulators based on Lyapunov stable theory. Finally, two 2-DOF reconfigurable manipulators with different configurations are employed to verify the effectiveness of the proposed scheme in numerical simulation. The results demonstrate that one joint’s fault does not affect other joints and the sensor fault can be identified precisely by the proposed decentralized sliding mode observer.

  20. Compressive sensing based spinning mode detections by in-duct microphone arrays

    Science.gov (United States)

    Yu, Wenjun; Huang, Xun

    2016-05-01

    This paper presents a compressive sensing based experimental method for detecting spinning modes of sound waves propagating inside a cylindrical duct system. This method requires fewer dynamic pressure sensors than the number required by the Shannon-Nyquist sampling theorem so long as the incident waves are sparse in spinning modes. In this work, the proposed new method is firstly validated by preparing some of the numerical simulations with representative set-ups. Then, a duct acoustic testing rig with a spinning mode synthesiser and an in-duct microphone array is built to experimentally demonstrate the new approach. Both the numerical simulations and the experiment results are satisfactory, even when the practical issue of the background noise pollution is taken into account. The approach is beneficial for sensory array tests of silent aeroengines in particular and some other engineering systems with duct acoustics in general.

  1. A Clustering Ensemble approach based on the similarities in 2-mode social networks

    Institute of Scientific and Technical Information of China (English)

    SU Bao-ping; ZHANG Meng-jie

    2014-01-01

    For a particular clustering problems, selecting the best clustering method is a challenging problem.Research suggests that integrate the multiple clustering can improve the accuracy of clustering ensemble greatly. A new clustering ensemble approach based on the similarities in 2-mode networks is proposed in this paper. First of all, the data object and the initial clustering clusters transform into 2-mode networks, then using the similarities in 2-mode networks to calculate the similarity between different clusters iteratively to refine the adjacency matrix , K-means algorithm is finally used to get the final clustering, then obtain the final clustering results.The method effectively use the similarity between different clusters, example shows the feasibility of this method.

  2. String Theory Based Predictions for Novel Collective Modes in Strongly Interacting Fermi Gases

    CERN Document Server

    Bantilan, H; Ishii, T; Lewis, W E; Romatschke, P

    2016-01-01

    Very different strongly interacting quantum systems such as Fermi gases, quark-gluon plasmas formed in high energy ion collisions and black holes studied theoretically in string theory are known to exhibit quantitatively similar damping of hydrodynamic modes. It is not known if such similarities extend beyond the hydrodynamic limit. Do non-hydrodynamic collective modes in Fermi gases with strong interactions also match those from string theory calculations? In order to answer this question, we use calculations based on string theory to make predictions for novel types of modes outside the hydrodynamic regime in trapped Fermi gases. These predictions are amenable to direct testing with current state-of-the-art cold atom experiments.

  3. Estimation of Linear Viscoelasticity of Polymer Melts in Molecular Dynamics Simulations Based on Relaxation Mode Analysis

    Science.gov (United States)

    Iwaoka, Nobuyuki; Hagita, Katsumi; Takano, Hiroshi

    2014-03-01

    On the basis of relaxation mode analysis (RMA), we present an efficient method to estimate the linear viscoelasticity of polymer melts in a molecular dynamics (MD) simulation. Slow relaxation phenomena appeared in polymer melts cause a problem that a calculation of the stress relaxation function in MD simulations, especially in the terminal time region, requires large computational efforts. Relaxation mode analysis is a method that systematically extracts slow relaxation modes and rates of the polymer chain from the time correlation of its conformations. We show the computational cost may be drastically reduced by combining a direct calculation of the stress relaxation function based on the Green-Kubo formula with the relaxation rates spectra estimated by RMA. N. I. acknowledges the Graduate School Doctoral Student Aid Program from Keio University.

  4. FMEA Based Risk Assessment of Component Failure Modes in Industrial Radiography

    CERN Document Server

    Pandey, Alok; Sonawane, A U; Rawat, Prashant S

    2016-01-01

    Industrial radiography has its inimitable role in non-destructive examinations. Industrial radiography devices, consisting of significantly high activity of the radioisotopes, are operated manually by remotely held control unit. Malfunctioning of these devices may cause potential exposure to the operator and nearby public, and thus should be practiced under a systematic risk control. To ensure the radiation safety, proactive risk assessment should be implemented. Risk assessment in industrial radiography using the Failure Modes & Effect Analysis (FMEA) for the design and operation of industrial radiography exposure devices has been carried out in this study. Total 56 component failure modes were identified and Risk Priority Numbers (RPNs) were assigned by the FMEA expert team, based on the field experience and reported failure data of various components. Results shows all the identified failure modes have RPN in the range of 04 to 216 and most of the higher RPN are due to low detectability and high severi...

  5. BPF-based reconstruction algorithm for multiple rotation-translation scan mode

    Institute of Scientific and Technical Information of China (English)

    Ming Chen; Huitao Zhang; Peng Zhang

    2008-01-01

    In industrial CT, it is often required to inspect large objects using short line-detectors. To acquire the complete CT data for the scanning slice of large objects using short line-detectors, some multi-scan modes have been developed. But the existing methods reconstructing an image from the data scanned by multi-scan modes have to rebin the data into fan-beam or parallel-beam form via data interpolation. The data rebinning process not only increases great computational cost, but also degrades image resolution. In this paper, we propose a backprojection-filtration (BPF)-based reconstruction algorithm for rotation-translation (RT) multi-scan mode. An important feature of the proposed algorithm is that data rebinning process is not introduced. The simulation results have verified the validity of the proposed algorithm.

  6. Frequency-shaped and observer-based discrete-time sliding mode control

    CERN Document Server

    Mehta, Axaykumar

    2015-01-01

    It is well established that the sliding mode control strategy provides an effective and robust method of controlling the deterministic system due to its well-known invariance property to a class of bounded disturbance and parameter variations. Advances in microcomputer technologies have made digital control increasingly popular among the researchers worldwide. And that led to the study of discrete-time sliding mode control design and its implementation. This brief presents, a method for multi-rate frequency shaped sliding mode controller design based on switching and non-switching type of reaching law. In this approach, the frequency dependent compensator dynamics are introduced through a frequency-shaped sliding surface by assigning frequency dependent weighing matrices in a linear quadratic regulator (LQR) design procedure. In this way, the undesired high frequency dynamics or certain frequency disturbance can be eliminated. The states are implicitly obtained by measuring the output at a faster rate than th...

  7. Study of Social Integrity Behavioral Mode Based On Multi-agent System

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2013-06-01

    Full Text Available Social integrity deficiency has become the main obstacle and prominent bottleneck to the construction of a harmonious society. Under this serious circumstance, paying attention to the problem and finding a solution has become an important issue we are faced with contemporarily. Former studies by some scholars have mainly centered on the basis of regime and education and some conclusions have been made. This paper, from the perspective of Multi-agent system, analyses the behavioral mode of the social integrity system and describes the process of emergence from the micro level to the macro one. Based on the Multi-agent system stimulus-response principle, it constructs the basic behavioral mode of social integrity; based on the adaptive-learning theory, it constructs the whole behavioral mode; and based on the evolution of agent, it constructs the level-emerge mode, which will provide a new point of view for the research of the social integrity system. According to this, some resolutions can be achieved to the issue mentioned above, which builds scientific reasonable policy basis and gives theoretical guidance for the central and local government in solving the widespread lack of social integrity.

  8. Shock Position Control for Mode Transition in a Turbine Based Combined Cycle Engine Inlet Model

    Science.gov (United States)

    Csank, Jeffrey T.; Stueber, Thomas J.

    2013-01-01

    A dual flow-path inlet for a turbine based combined cycle (TBCC) propulsion system is to be tested in order to evaluate methodologies for performing a controlled inlet mode transition. Prior to experimental testing, simulation models are used to test, debug, and validate potential control algorithms which are designed to maintain shock position during inlet disturbances. One simulation package being used for testing is the High Mach Transient Engine Cycle Code simulation, known as HiTECC. This paper discusses the development of a mode transition schedule for the HiTECC simulation that is analogous to the development of inlet performance maps. Inlet performance maps, derived through experimental means, describe the performance and operability of the inlet as the splitter closes, switching power production from the turbine engine to the Dual Mode Scram Jet. With knowledge of the operability and performance tradeoffs, a closed loop system can be designed to optimize the performance of the inlet. This paper demonstrates the design of the closed loop control system and benefit with the implementation of a Proportional-Integral controller, an H-Infinity based controller, and a disturbance observer based controller; all of which avoid inlet unstart during a mode transition with a simulated disturbance that would lead to inlet unstart without closed loop control.

  9. Detection of perturbed quantization class stego images based on possible change modes

    Science.gov (United States)

    Zhang, Yi; Liu, Fenlin; Yang, Chunfang; Luo, Xiangyang; Song, Xiaofeng

    2015-11-01

    To improve the detection performance for perturbed quantization (PQ) class [PQ, energy-adaptive PQ (PQe), and texture-adaptive PQ (PQt)] stego images, a detection method based on possible change modes is proposed. First, by using the relationship between the changeable coefficients used for carrying secret messages and the second quantization steps, the modes having even second quantization steps are identified as possible change modes. Second, by referencing the existing features, the modified features that can accurately capture the embedding changes based on possible change modes are extracted. Next, feature sensitivity analyses based on the modifications performed before and after the embedding are carried out. These analyses show that the modified features are more sensitive to the original features. Experimental results indicate that detection performance of the modified features is better than that of the corresponding original features for three typical feature models [Cartesian calibrated PEVny (ccPEV), Cartesian calibrated co-occurrence matrix features (CF), and JPEG rich model (JRM)], and the integrated feature consisting of enhanced histogram features (EHF) and the modified JRM outperforms two current state-of-the-art feature models, namely, phase aware projection model (PHARM) and Gabor rich model (GRM).

  10. Multi-Scale Pixel-Based Image Fusion Using Multivariate Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Naveed ur Rehman

    2015-05-01

    Full Text Available A novel scheme to perform the fusion of multiple images using the multivariate empirical mode decomposition (MEMD algorithm is proposed. Standard multi-scale fusion techniques make a priori assumptions regarding input data, whereas standard univariate empirical mode decomposition (EMD-based fusion techniques suffer from inherent mode mixing and mode misalignment issues, characterized respectively by either a single intrinsic mode function (IMF containing multiple scales or the same indexed IMFs corresponding to multiple input images carrying different frequency information. We show that MEMD overcomes these problems by being fully data adaptive and by aligning common frequency scales from multiple channels, thus enabling their comparison at a pixel level and subsequent fusion at multiple data scales. We then demonstrate the potential of the proposed scheme on a large dataset of real-world multi-exposure and multi-focus images and compare the results against those obtained from standard fusion algorithms, including the principal component analysis (PCA, discrete wavelet transform (DWT and non-subsampled contourlet transform (NCT. A variety of image fusion quality measures are employed for the objective evaluation of the proposed method. We also report the results of a hypothesis testing approach on our large image dataset to identify statistically-significant performance differences.

  11. Application of Fault Location Mode Based on Travelling Waves for Neutral Non-effective Grounding Systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feeders using fault generated current and voltage transient traveling waves was investigated.The characteristics of transient traveling waves resulted from each short circuit fault and their transmission disciplinarian in distribution feeders are analyzed.This paper proposed that double end travelling waves theory which measures arriving time of fault initiated surge at both ends of the monitored line is fit for distribution feeders but single end traveling waves theory not.According to different distribution feeders,on the basis of analyzing original traveling waves reflection rule in line terminal, Current-voltage mode,voltage-voltage mode and current-current mode for fault location based on traveling waves are proposed and aerial mode component of original traveling waves is used to realize fault location.Experimental test verify the feasibility and correctness of the proposed method.

  12. Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory

    Science.gov (United States)

    Pu, Weihua; He, Xiangming; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

    2005-12-01

    A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.

  13. A Comparative Study of Empirical Mode Decomposition-Based Filtering for Impact Signal

    Directory of Open Access Journals (Sweden)

    Liwei Zhan

    2016-12-01

    Full Text Available The Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN has been used to propose a new method for filtering time series originating from nonlinear systems. The filtering method is based on fuzzy entropy and a new waveform. A new waveform is defined wherein Intrinsic Mode Functions (IMFs—which are obtained by CEEMDAN algorithm—are firstly sorted in ascending order (the sorted IMFs is symmetric about center point, because at any point, the mean value of the envelope line defined by the local maxima and the local minima is zero, and the energy of the sorted IMFs are calculated, respectively. Finally, the new waveform with axial symmetry can be obtained. The complexity of the new waveform can be quantified by fuzzy entropy. The relevant modes (noisy signal modes and useful signal modes can be identified by the difference between the fuzzy entropy of the new waveform and the next adjacent new waveform. To evaluate the filter performance, CEEMDAN and sample entropy, Ensemble Empirical Mode Decomposition (EEMD and fuzzy entropy, and EEMD and sample entropy were used to filter the synthesizing signals with various levels of input signal-to-noise ratio (SNRin. In particular, this approach is successful in filtering impact signal. The results of the filtering are evaluated by a de-trended fluctuation analysis (DFA algorithm, revised mean square error (RMSE, and revised signal-to-noise ratio (RSNR, respectively. The filtering results of simulated and impact signal show that the filtering method based on CEEMDAN and fuzzy entropy outperforms other signal filtering methods.

  14. Failure mode and effect analysis-based quality assurance for dynamic MLC tracking systems

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, Amit; Dieterich, Sonja; Svatos, Michelle; Keall, Paul [Stanford University, Stanford, California 94394 (United States); Varian Medical Systems, Palo Alto, California 94304 (United States); Stanford University, Stanford, California 94394 (United States)

    2010-12-15

    Purpose: To develop and implement a failure mode and effect analysis (FMEA)-based commissioning and quality assurance framework for dynamic multileaf collimator (DMLC) tumor tracking systems. Methods: A systematic failure mode and effect analysis was performed for a prototype real-time tumor tracking system that uses implanted electromagnetic transponders for tumor position monitoring and a DMLC for real-time beam adaptation. A detailed process tree of DMLC tracking delivery was created and potential tracking-specific failure modes were identified. For each failure mode, a risk probability number (RPN) was calculated from the product of the probability of occurrence, the severity of effect, and the detectibility of the failure. Based on the insights obtained from the FMEA, commissioning and QA procedures were developed to check (i) the accuracy of coordinate system transformation, (ii) system latency, (iii) spatial and dosimetric delivery accuracy, (iv) delivery efficiency, and (v) accuracy and consistency of system response to error conditions. The frequency of testing for each failure mode was determined from the RPN value. Results: Failures modes with RPN{>=}125 were recommended to be tested monthly. Failure modes with RPN<125 were assigned to be tested during comprehensive evaluations, e.g., during commissioning, annual quality assurance, and after major software/hardware upgrades. System latency was determined to be {approx}193 ms. The system showed consistent and accurate response to erroneous conditions. Tracking accuracy was within 3%-3 mm gamma (100% pass rate) for sinusoidal as well as a wide variety of patient-derived respiratory motions. The total time taken for monthly QA was {approx}35 min, while that taken for comprehensive testing was {approx}3.5 h. Conclusions: FMEA proved to be a powerful and flexible tool to develop and implement a quality management (QM) framework for DMLC tracking. The authors conclude that the use of FMEA-based QM ensures

  15. A Turbine Based Combined Cycle Engine Inlet Model and Mode Transition Simulation Based on HiTECC Tool

    Science.gov (United States)

    Csank, Jeffrey T.; Stueber, Thomas J.

    2012-01-01

    An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10- by 10-Foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.

  16. Adaptive Terminal Sliding Mode NDO-Based Control of Underactuated AUV in Vertical Plane

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-01-01

    Full Text Available The depth tracking issue of underactuated autonomous underwater vehicle (AUV in vertical plane is addressed in this paper. Considering the complicated dynamics and kinematics model for underactuated AUV, a more simplified model is obtained based on assumptions. Then a nonlinear disturbance observer (NDO is presented to estimate the external disturbance acting on AUV, and an adaptive terminal sliding mode control (ATSMC based on NDO is applied to enhance the depth tracking performance of underactuated AUV considering both internal and external disturbance. Compared with the traditional sliding mode controller, the static error and chattering problem of the depth tracking process have been clearly improved by adopting NDO-based ATSMC. The stability of control system is proven to be guaranteed according to Lyapunov theory. In the end, simulation results imply that the proposed controller owns strong robustness and satisfied control effectiveness in comparison with the traditional controller.

  17. On-chip two-mode division multiplexing using tapered directional coupler-based mode multiplexer and demultiplexer

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Da Ros, Francesco

    2013-01-01

    ), and large fabrication tolerance (20 nm) are measured. An on-chip mode multiplexing experiment is carried out on the fabricated circuit with non return-to-zero (NRZ) on-off keying (OOK) signals at 40 Gbit/s. The experimental results show clear eye diagrams and moderate power penalty for both TE0 and TE1...

  18. Energy-Efficient Next-Generation Passive Optical Networks Based on Sleep Mode and Heuristic Optimization

    Science.gov (United States)

    Zulai, Luis G. T.; Durand, Fábio R.; Abrão, Taufik

    2015-05-01

    In this article, an energy-efficiency mechanism for next-generation passive optical networks is investigated through heuristic particle swarm optimization. Ten-gigabit Ethernet-wavelength division multiplexing optical code division multiplexing-passive optical network next-generation passive optical networks are based on the use of a legacy 10-gigabit Ethernet-passive optical network with the advantage of using only an en/decoder pair of optical code division multiplexing technology, thus eliminating the en/decoder at each optical network unit. The proposed joint mechanism is based on the sleep-mode power-saving scheme for a 10-gigabit Ethernet-passive optical network, combined with a power control procedure aiming to adjust the transmitted power of the active optical network units while maximizing the overall energy-efficiency network. The particle swarm optimization based power control algorithm establishes the optimal transmitted power in each optical network unit according to the network pre-defined quality of service requirements. The objective is controlling the power consumption of the optical network unit according to the traffic demand by adjusting its transmitter power in an attempt to maximize the number of transmitted bits with minimum energy consumption, achieving maximal system energy efficiency. Numerical results have revealed that it is possible to save 75% of energy consumption with the proposed particle swarm optimization based sleep-mode energy-efficiency mechanism compared to 55% energy savings when just a sleeping-mode-based mechanism is deployed.

  19. A Multi-agent Supply Chain Information Coordination Mode Based on Cloud Computing

    Directory of Open Access Journals (Sweden)

    Wuxue Jiang

    2013-11-01

    Full Text Available  In order to improve the high efficiency and security of supply chain information coordination under cloud computing environment, this paper proposes a supply chain information coordination mode based on cloud computing. This mode has two basic statuses which are online status and offline status. At the online status, cloud computing center is responsible for coordinating the whole supply chain information. At the offline status, information exchange can be realized among different nodes by using the pre-backup supply chain information and network address of other nodes. This coordination mode coordinates the whole supply chain information through the cloud computing center at the online status and maximizes the overall benefit. Meanwhile, the offline status effectively avoids the risks to the whole supply chain brought by the overdependence of cloud computing on network and the high information concentration. The two statuses have good customers’ satisfaction and higher order finished rate in supply chain. The simulation experiment based on multi-Agent verifies the effectiveness of this mode in this paper.

  20. Hemagglutination detection for blood typing based on waveguide-mode sensors

    Directory of Open Access Journals (Sweden)

    Hiroki Ashiba

    2015-03-01

    Full Text Available ABO and Rh(D blood typing is one of the most important tests performed prior to blood transfusion. Although on-site blood testing is desirable for expedient blood transfusion procedure, most conventional methods and instruments lack the required usability or portability. Here, we describe a novel method, based on the detection of hemagglutination using an optical waveguide-mode sensor, for on-site use. The reflectance spectrum of blood alone and that of blood mixed with antibody reagents was measured using the waveguide-mode sensor. Differences in reflectance by agglutinated and non-agglutinated blood samples were observed at the bottom of the spectral dips; due to differences in the manner in which red blood cells interacted with the surface of the sensor chip. Following the addition of the antibody, blood types A, B, O, and AB were clearly distinguishable and Rh(D typing was also possible using the waveguide-mode sensor. Furthermore, the waveguide-mode-based measurement exhibited the potential to detect weak agglutination, which is difficult for human eyes to distinguish. Thus, this method holds great promise for application in novel on-site test instruments.

  1. Dual-mode immunoassay based on shape code and infrared absorption fingerprint signals of silica nanorods.

    Science.gov (United States)

    Zhao, Pengfei; Ni, Ran; Wang, Kexin; Hong, Xia; Ding, Yadan; Cong, Tie; Liu, Junping; Zhao, Huiying

    2017-07-01

    Silica nanorods were synthesized through a simple one-pot emulsion-droplet-based growth method, in which tetraethylorthosilicate (TEOS) was used as the silica source, ammonia as the catalyst, and polyvinylpyrrolidone (PVP) as the structure-directing agent and stabilizer. By controlling hydrolysis and condensation in the reaction process, we regulated the aspect ratios and the infrared (IR) absorption fingerprint signals (the transverse optical and the longitudinal optical phonon modes) of the silica nanorods. Based on this, a dual-mode immunoassay was performed for detecting model target analyte, human IgG. The shape code of the silica nanorods was used for simple, rapid qualitative, and sensitive semi-quantitative immunoassay by using a conventional optical microscope. The characteristic IR absorption fingerprint signals of the silica nanorods allowed for reliable quantitative immunoassay with good selectivity and high specificity. The detection limit and the linear range were found out to be 0.5 pM and 1 pM-10 nM, respectively. We expect that such dual-mode immunoassay could be applied for the detection of other analytes, such as protein, nucleic acids, bacteria, viruses, explosives, toxins, and so on. Graphical abstract A simple dual-mode immunoassay was performed using the shape code and infrared absorption fingerprint signals of silica nanorods as detection signals.

  2. Carrier-Based Common Mode Voltage Control Techniques in Three-Level Diode-Clamped Inverter

    Directory of Open Access Journals (Sweden)

    Pradyumn Chaturvedi

    2012-01-01

    Full Text Available Switching converters are used in electric drive applications to produce variable voltage, variable frequency supply which generates harmful large dv/dt and high-frequency common mode voltages (CMV. Multilevel inverters generate lower CMV as compared to conventional two-level inverters. This paper presents simple carrier-based technique to control the common mode voltages in multilevel inverters using different structures of sine-triangle comparison method such as phase disposition (PD, phase opposition disposition (POD by adding common mode voltage offset signal to actual reference voltage signal. This paper also presented the method to optimize the magnitude of this offset signal to reduce CMV and total harmonic distortion in inverter output voltage. The presented techniques give comparable performance as obtained in complex space vector-based control strategy, in terms of number of commutations, magnitude, and rate of change of CMV and harmonic profile of inverter output voltage. Simulation and experimental results presented confirm the effectiveness of the proposed techniques to control the common mode voltages.

  3. Sliding Mode Disturbance Observer-Based Fractional Second-Order Nonsingular Terminal Sliding Mode Control for PMSM Position Regulation System

    Directory of Open Access Journals (Sweden)

    Hong-Ru Li

    2015-01-01

    Full Text Available This paper investigates the position regulation problem of permanent magnet synchronous motor (PMSM subject to parameter uncertainties and external disturbances. A novel fractional second-order nonsingular terminal sliding mode control (F2NTSMC is proposed and the finite time stability of the closed-loop system is ensured. A sliding mode disturbance observer (SMDO is developed to estimate and make feedforward compensation for the lumped disturbances of the PMSM system. Moreover, the finite-time convergence of estimation errors can be guaranteed. The control scheme combining F2NTSMC and SMDO can not only improve performance of the closed-loop system and attenuate disturbances, but also reduce chattering effectively. Simulation results show that the proposed control method can obtain satisfactory position tracking performance and strong robustness.

  4. A Parallel Product-Convolution approach for representing the depth varying Point Spread Functions in 3D widefield microscopy based on principal component analysis.

    Science.gov (United States)

    Arigovindan, Muthuvel; Shaevitz, Joshua; McGowan, John; Sedat, John W; Agard, David A

    2010-03-29

    We address the problem of computational representation of image formation in 3D widefield fluorescence microscopy with depth varying spherical aberrations. We first represent 3D depth-dependent point spread functions (PSFs) as a weighted sum of basis functions that are obtained by principal component analysis (PCA) of experimental data. This representation is then used to derive an approximating structure that compactly expresses the depth variant response as a sum of few depth invariant convolutions pre-multiplied by a set of 1D depth functions, where the convolving functions are the PCA-derived basis functions. The model offers an efficient and convenient trade-off between complexity and accuracy. For a given number of approximating PSFs, the proposed method results in a much better accuracy than the strata based approximation scheme that is currently used in the literature. In addition to yielding better accuracy, the proposed methods automatically eliminate the noise in the measured PSFs.

  5. Terminal Sliding Mode-Based Consensus Tracking Control for Networked Uncertain Mechanical Systems on Digraphs.

    Science.gov (United States)

    Chen, Gang; Song, Yongduan; Guan, Yanfeng

    2016-12-29

    This brief investigates the finite-time consensus tracking control problem for networked uncertain mechanical systems on digraphs. A new terminal sliding-mode-based cooperative control scheme is developed to guarantee that the tracking errors converge to an arbitrarily small bound around zero in finite time. All the networked systems can have different dynamics and all the dynamics are unknown. A neural network is used at each node to approximate the local unknown dynamics. The control schemes are implemented in a fully distributed manner. The proposed control method eliminates some limitations in the existing terminal sliding-mode-based consensus control methods and extends the existing analysis methods to the case of directed graphs. Simulation results on networked robot manipulators are provided to show the effectiveness of the proposed control algorithms.

  6. Research of Compound Control for DC Motor System Based on Global Sliding Mode Disturbance Observer

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-01-01

    Full Text Available Aiming at the problems of modeling errors, parameter variations, and load moment disturbances in DC motor control system, one global sliding mode disturbance observer (GSMDO is proposed based on the global sliding mode (GSM control theory. The output of GSMDO is used as the disturbance compensation in control system, which can improve the robust performance of DC motor control system. Based on the designed GSMDO in inner loop, one compound controller, composed of a feedback controller and a feedforward controller, is proposed in order to realize the position tracking of DC motor system. The gains of feedback controller are obtained by means of linear quadratic regulator (LQR optimal control theory. Simulation results present that the proposed control scheme possesses better tracking properties and stronger robustness against modeling errors, parameter variations, and friction moment disturbances. Moreover, its structure is simple; therefore it is easy to be implemented in engineering.

  7. Robust passive control for a class of uncertain neutral systems based on sliding mode observer.

    Science.gov (United States)

    Liu, Zhen; Zhao, Lin; Kao, Yonggui; Gao, Cunchen

    2017-01-01

    The passivity-based sliding mode control (SMC) problem for a class of uncertain neutral systems with unmeasured states is investigated. Firstly, a particular non-fragile state observer is designed to generate the estimations of the system states, based upon which a novel integral-type sliding surface function is established for the control process. Secondly, a new sufficient condition for robust asymptotic stability and passivity of the resultant sliding mode dynamics (SMDs) is obtained in terms of linear matrix inequalities (LMIs). Thirdly, the finite-time reachability of the predesigned sliding surface is ensured by resorting to a novel adaptive SMC law. Finally, the validity and superiority of the scheme are justified via several examples.

  8. Extended observer based on adaptive second order sliding mode control for a fixed wing UAV.

    Science.gov (United States)

    Castañeda, Herman; Salas-Peña, Oscar S; León-Morales, Jesús de

    2017-01-01

    This paper addresses the design of attitude and airspeed controllers for a fixed wing unmanned aerial vehicle. An adaptive second order sliding mode control is proposed for improving performance under different operating conditions and is robust in presence of external disturbances. Moreover, this control does not require the knowledge of disturbance bounds and avoids overestimation of the control gains. Furthermore, in order to implement this controller, an extended observer is designed to estimate unmeasurable states as well as external disturbances. Additionally, sufficient conditions are given to guarantee the closed-loop stability of the observer based control. Finally, using a full 6 degree of freedom model, simulation results are obtained where the performance of the proposed method is compared against active disturbance rejection based on sliding mode control.

  9. A MIXED MODE FRACTURE CRITERION BASED ON THE MAXIMUM TANGENTIAL STRESS IN BRITTLE INCLUSION

    Institute of Scientific and Technical Information of China (English)

    Ji Changjiang; Li Zhonghua; Sun Jun

    2005-01-01

    A closed-form solution for predicting the tangential stress of an inclusion located in mixed mode Ⅰ and Ⅱ crack tip field was developed based on the Eshelby equivalent inclusion theory. Then a mixed mode fracture criterion, including the fracture direction and the critical load, was established based on the maximum tangential stress in the inclusion for brittle inclusioninduced fracture materials. The proposed fracture criterion is a function of the inclusion fracture stress, its size and volume fraction, as well as the elastic constants of the inclusion and the matrix material. The present criterion will reduce to the conventional one as the inclusion having the same elastic behavior as the matrix material. The proposed solutions are in good agreement with detailed finite element analysis and measurement.

  10. Simulations of mode reduction with an intracavity etalon in an RF-Linac based FEL

    Science.gov (United States)

    Oepts, D.; van der Meer, A. F. G.; Best, R. W. B.; van Amersfoort, P. W.; Colson, W. B.

    1989-12-01

    Coherence between successive light pulses from an rf-linac based FEL can be induced by means of an intracavity interferometric element such as an etalon. This considerably reduces the number of active cavity modes and facilitates the selection of a single narrow line from the laser output. Computer simulations for the operation of an etalon in the FELIX design are shown. The model based on the wave equation driven by single particles has been applied in simulations using a small number (up to six) of initially independent pulses. The case with 40 separate pulses in the cavity is treated with a simpler model. The simulations show that a low-finesse etalon suffices to obtain a large degree of coherence between successive pulses. Saturated operation in a reduced number of modes, but with the same total power, is attained with a delay of a few microseconds.

  11. Flattop pulse generation based on the combined action of active mode locking and nonlinear polarization rotation.

    Science.gov (United States)

    Fang, Xiaohui; Wai, P K A; Lu, Chao; Chen, Jinhua

    2014-02-10

    A pulse-width-tunable 10 GHz flattop pulse (FTP) train is generated based on the combined action of active mode locking and nonlinear polarization rotation pulse shaping. Although the setup was previously used for other applications, the mechanism of FTP generation based on it is first analyzed and confirmed in the experiment. An FTP with pulse width tunable from 12 to 20 ps by changing polarization controllers is generated within the wavelength tuning range of 20 nm. The generated pulse reveals good stability, with the side mode suppression ratio of 65 dB, timing jitter of 92 fs, and amplitude fluctuation of 0.36%.

  12. HOLD MODE BASED DYNAMIC PRIORITY LOAD ADAPTIVE INTERPICONET SCHEDULING FOR BLUETOOTH SCATTERNETS

    Directory of Open Access Journals (Sweden)

    G.S. Mahalakshmi

    2011-09-01

    Full Text Available Scheduling in piconets has emerged as a challenging research area. Interpiconet scheduling focuses on when a bridge is switched among various piconets and how a bridge node communicates with the masters in different piconets. This paper proposes an interpiconet scheduling algorithm named, hold mode based dynamic traffic priority load adaptive scheduling. The bridges are adaptively switched between the piconets according to various traffic loads. The main goal is to maximize the utilization of the bridge by reducing the bridge switch wastes, utilize intelligent decision making algorithm, resolve conflict between the masters, and allow negotiation for bridge utilization in HDPLIS using bridge failure-bridge repair procedure . The Hold mode - dynamic traffic - priority based - load adaptive scheduling reduces the number of bridge switch wastes and hence increases the efficiency of the bridge which results in increased performance of the system.

  13. Chaos Control in Memristor-based Oscillators Using Intelligent Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Amir Hossein Abolmasoumi

    2014-10-01

    Full Text Available In this paper, Intelligent Sliding Mode Control of chaos in a memristor- based Chua’s oscillator is investigated. In order to gain stabilization and tracking of a sinusoidal input, an appropriate sliding surface is proposed and sliding gain is tuned. Also, to avoid the chattering phenomenon in traditional sliding mode controller, and to reduce the hitting time of the controlled system, an especial genetic algorithm optimization method is suggested. By defining a new objective function and searching for optimal the controller parameters the convergence time and chattering are reduced considerably. The usefulness of the proposed controller with intelligent tuning method for chaos control of memristorbased oscillators is demonstrated in memristor- based Chua's circuit.

  14. Synchronizing Spatiotemporal Chaos via a Composite Disturbance Observer-Based Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Congyan Chen

    2014-01-01

    Full Text Available The sliding mode control schemes are investigated to synchronize two spatiotemporal chaotic systems, which are two arrays of a large number of coupled chaotic oscillators. Firstly, sliding mode manifolds with the desired performance are designed. The asymptotic convergence to the origin of the synchronization errors is also proved. However, the terms from parameter fluctuations in equivalent controls are usually impossible to be measured directly. So we regard them as lumped disturbances, but, for practical application, it is difficult to obtain the upper bound of lumped disturbances in advance which often results in a conservative sliding mode control law with large control effort, causing a large amount of chattering. To reduce the chattering and improve the performance of the system, a disturbance observer is designed to estimate the lumped disturbances. A composite synchronization controller that consists of a sliding mode feedback part and a feedforward compensation part based on disturbance observer is developed. The numerical simulation results are presented to show the effectiveness of the proposed methods.

  15. Phase-Sensitive Noise Suppression in a Photoacoustic Sensor based on Acoustic Circular Membrane Modes

    CERN Document Server

    Lassen, Mikael; Balslev-Harder, David; Petersen, Jan C

    2014-01-01

    A photoacoustic (PA) sensor based on higher order acoustic modes is demonstrated. The PA sensor is designed to enhance the gas-detection performance and simultaneously suppress ambient noise sources (e.g. flow noise, electrical noise and external acoustic noise). Two microphones are used and positioned such that the PA signals are ($\\pi$) out of phase. Ambient acoustic noise are approximately in the same phase and will be subtracted and thus improve the SNR. In addition, by placing the gas in- and outlets so that the gas flows through the node of the first higher order membrane mode the coupling of flow noise is approximately 20 dB lower compared with flow through the fundamental mode at 5 L/min. The noise reduction and thus the increase in sensitivity is demonstrated by measuring vibrational lines of methanol and methane using a broadband interband cascade laser emitting radiation at 3.38 $\\mu$m. A signal-to-noise improvement of 20 (26 dB) using higher order modes are demonstrated compared with the fundament...

  16. MESHLESS METHOD FOR 2D MIXED-MODE CRACK PROPAGATION BASED ON VORONOI CELL

    Institute of Scientific and Technical Information of China (English)

    LouLullang; ZengPan

    2003-01-01

    A meshless method integrated with linear elastic fracture mechanics (LEFM) is presented for 2D mixed-mode crack propagation analysis. The domain is divided automatically into sub-domains based on Voronoi cells, which are used for quadrature for the potential energy. The continuous crack propagation is simulated with an incremental crack-extension method which assumes a piecewise linear discretization of the unknown crack path. For each increment of the crack extension, the meshless method is applied to carry out a stress analysis of the cracked structure. The J-integral, which can be decomposed into mode I and mode II for mixed-mode crack, is used for the evaluation of the stress intensity factors (SIFs). The crack-propagation direction, predicted on an incremental basis, is computed by a criterion defined in terms of the SIFs. The flowchart of the proposed procedure is presented and two numerical problems are analyzed with this method. The meshless results agree well with the experimental ones, which validates the accuracy and efficiency of the method.

  17. AN EVALUATION OF PRIMARY DATA-COLLECTION MODES IN AN ADDRESS-BASED SAMPLING DESIGN.

    Science.gov (United States)

    Amaya, Ashley; Leclere, Felicia; Carris, Kari; Liao, Youlian

    2015-01-01

    As address-based sampling becomes increasingly popular for multimode surveys, researchers continue to refine data-collection best practices. While much work has been conducted to improve efficiency within a given mode, additional research is needed on how multimode designs can be optimized across modes. Previous research has not evaluated the consequences of mode sequencing on multimode mail and phone surveys, nor has significant research been conducted to evaluate mode sequencing on a variety of indicators beyond response rates. We conducted an experiment within the Racial and Ethnic Approaches to Community Health across the U.S. Risk Factor Survey (REACH U.S.) to evaluate two multimode case-flow designs: (1) phone followed by mail (phone-first) and (2) mail followed by phone (mail-first). We compared response rates, cost, timeliness, and data quality to identify differences across case-flow design. Because surveys often differ on the rarity of the target population, we also examined whether changes in the eligibility rate altered the choice of optimal case flow. Our results suggested that, on most metrics, the mail-first design was superior to the phone-first design. Compared with phone-first, mail-first achieved a higher yield rate at a lower cost with equivalent data quality. While the phone-first design initially achieved more interviews compared to the mail-first design, over time the mail-first design surpassed it and obtained the greatest number of interviews.

  18. A few mode fiber curvature sensor based on two spherical-shape structures modal interferometer

    Science.gov (United States)

    Fu, Xinghu; Wang, Siwen; Zhang, Shunyang; Liu, Qin; Li, Qifeng; Xie, Haiyang; Fu, Guangwei; Bi, Weihong; Li, Yanjun

    2016-10-01

    In order to improve the equilibrium between fiber sensor performance and cost, a curvature sensor based on Few Mode Fiber(FMF) is proposed. A length of FMF is spliced with waist enlarge between two Single mode Fibers(SMFs) to form two spherical- shape structure. Fiber core mode interfere with clad mode due to the excite and couple function of spherical-shape structure, respectively. The phase difference between the cladding and core regions of the fiber changes with the external strain increase, and then the interference spectrum changes. Two sensors with different length of FMF are fabricated, and the transmission spectrum are obtained. The result shows the optical power at certain wavelength is increasing with the curvature increasing. When the curvature range is 0 0.42m-1 and the FMF is 5.7cm, the curvature sensitivity can be 11.22dB/m-1. When the FMF is 5.9cm, the curvature sensitivity can be climbed to 14.08dB/m-1.

  19. Design of passive fault-tolerant controllers of a quadrotor based on sliding mode theory

    Directory of Open Access Journals (Sweden)

    Merheb Abdel-Razzak

    2015-09-01

    Full Text Available Abstract In this paper, sliding mode control is used to develop two passive fault tolerant controllers for an AscTec Pelican UAV quadrotor. In the first approach, a regular sliding mode controller (SMC augmented with an integrator uses the robustness property of variable structure control to tolerate partial actuator faults. The second approach is a cascaded sliding mode controller with an inner and outer SMC loops. In this configuration, faults are tolerated in the fast inner loop controlling the velocity system. Tuning the controllers to find the optimal values of the sliding mode controller gains is made using the ecological systems algorithm (ESA, a biologically inspired stochastic search algorithm based on the natural equilibrium of animal species. The controllers are tested using SIMULINK in the presence of two different types of actuator faults, partial loss of motor power affecting all the motors at once, and partial loss of motor speed. Results of the quadrotor following a continuous path demonstrated the effectiveness of the controllers, which are able to tolerate a significant number of actuator faults despite the lack of hardware redundancy in the quadrotor system. Tuning the controller using a faulty system improves further its ability to afford more severe faults. Simulation results show that passive schemes reserve their important role in fault tolerant control and are complementary to active techniques

  20. Residual lens effects in 2D mode of auto-stereoscopic lenticular-based switchable 2D/3D displays

    Science.gov (United States)

    Sluijter, M.; IJzerman, W. L.; de Boer, D. K. G.; de Zwart, S. T.

    2006-04-01

    We discuss residual lens effects in multi-view switchable auto-stereoscopic lenticular-based 2D/3D displays. With the introduction of a switchable lenticular, it is possible to switch between a 2D mode and a 3D mode. The 2D mode displays conventional content, whereas the 3D mode provides the sensation of depth to the viewer. The uniformity of a display in the 2D mode is quantified by the quality parameter modulation depth. In order to reduce the modulation depth in the 2D mode, birefringent lens plates are investigated analytically and numerically, by ray tracing. We can conclude that the modulation depth in the 2D mode can be substantially decreased by using birefringent lens plates with a perfect index match between lens material and lens plate. Birefringent lens plates do not disturb the 3D performance of a switchable 2D/3D display.

  1. A tunable comb filter using single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop

    Institute of Scientific and Technical Information of China (English)

    Ruan Juan; Zhang Wei-Gang; Zhang Hao; Geng Peng-Cheng; Bai Zhi-Yong

    2013-01-01

    A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated.The filter tunability is achieved by rotating the polarization controller.The spectral shift is dependent on rotation direction and the position of the polarization controller.In addition,the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.

  2. Singular Perturbation Theory-Based Qualitative Dynamics Investigation of Flywheel Energy Storage System in Discharge Mode

    OpenAIRE

    Weiya Zhang; Yongli Li; Xiaoyong Chang; Nan Wang

    2014-01-01

    An investigation on qualitative dynamics in a voltage-current dual-loop controlled flywheel energy storage system (FESS) operating in discharge mode is presented in this paper, providing novel insights into the effect of two-timescale characteristics on the safety and stability of energy transmission of FESS. Based on singular perturbation theory, a two-timescale approach is proposed to separate the FESS into the fast and slow subsystems. Stability analysis of the transient fixed points confi...

  3. Control and fault diagnosis based sliding mode observer of a multicellular converter: Hybrid approach

    KAUST Repository

    Benzineb, Omar

    2013-01-01

    In this article, the diagnosis of a three cell converter is developed. The hybrid nature of the system represented by the presence of continuous and discrete dynamics is taken into account in the control design. The idea is based on using a hybrid control and an observer-type sliding mode to generate residuals from the observation errors of the system. The simulation results are presented at the end to illustrate the performance of the proposed approach. © 2013 FEI STU.

  4. Localized Mode Enhanced Coupler Based on Quasi-One-Dimensional Photonic Crystal Microstrip

    Institute of Scientific and Technical Information of China (English)

    LI Yun-Hui; JIANG Hai-Tao; HE Li; LI Hong-Qiang; ZHANG Ye-Wen; CHEN Hong

    2004-01-01

    We propose a novel localized mode enhanced (LME) coupler based on quasi-one-dimensional photonic crystal microstrips, which is promising to be applied in wavelength division multiplexed microwave communication systems. Compared to the traditional microstrip coupler, the LME structure has two advantages: high efficiency and frequency selectivity. Even in a relatively far coupling distance, this structure can still achieve a high efficiency about 50%. The frequency selectivity can be realized by simply tuning the distance between two transmission lines.

  5. Fuzzy Sliding Mode Lateral Control of Intelligent Vehicle Based on Vision

    Directory of Open Access Journals (Sweden)

    Linhui Li

    2013-01-01

    Full Text Available The lateral control of intelligent vehicle is studied in this paper, with the intelligent vehicle DLUIV-1 based on visual navigation as the object of research. Firstly, the lateral control model based on visual preview is established. The kinematics model based on visual preview, including speed and other factors, is used to calculate the lateral error and direction error. Secondly, according to the characteristics of lateral control, an efficient strategy of intelligent vehicle lateral mode is proposed. The integration of the vehicle current lateral error and direction error is chosen as the parameter of the sliding mode switching function to design the sliding surface. The control variables are adjusted according to the fuzzy control rules to ensure that they meet the existence and reaching condition. The sliding mode switching function is regarded as the control objective, to ensure the stability of the steering wheel rotation. Simulation results show that the lateral controller can guarantee high path-tracking accuracy and strong robustness for the change of model parameters.

  6. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons.

    Science.gov (United States)

    Long, Yi; Du, Zhi-Jiang; Wang, Wei-Dong; Zhao, Guang-Yu; Xu, Guo-Qiang; He, Long; Mao, Xi-Wang; Dong, Wei

    2016-09-02

    Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM) optimized by particle swarm optimization (PSO) to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS) attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz), a three-layer wavelet packet analysis (WPA) is used for feature extraction, after which, the kernel principal component analysis (kPCA) is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA) is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance.

  7. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons

    Directory of Open Access Journals (Sweden)

    Yi Long

    2016-09-01

    Full Text Available Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM optimized by particle swarm optimization (PSO to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz, a three-layer wavelet packet analysis (WPA is used for feature extraction, after which, the kernel principal component analysis (kPCA is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance.

  8. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons

    Science.gov (United States)

    Long, Yi; Du, Zhi-Jiang; Wang, Wei-Dong; Zhao, Guang-Yu; Xu, Guo-Qiang; He, Long; Mao, Xi-Wang; Dong, Wei

    2016-01-01

    Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM) optimized by particle swarm optimization (PSO) to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS) attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz), a three-layer wavelet packet analysis (WPA) is used for feature extraction, after which, the kernel principal component analysis (kPCA) is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA) is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance. PMID:27598160

  9. GaSb-based single-mode distributed feedback lasers for sensing (Conference Presentation)

    Science.gov (United States)

    Gupta, James A.; Bezinger, Andrew; Lapointe, Jean; Poitras, Daniel; Aers, Geof C.

    2017-02-01

    GaSb-based tunable single-mode diode lasers can enable rapid, highly-selective and highly-sensitive absorption spectroscopy systems for gas sensing. In this work, single-mode distributed feedback (DFB) laser diodes were developed for the detection of various trace gases in the 2-3.3um range, including CO2, CO, HF, H2S, H2O and CH4. The lasers were fabricated using an index-coupled grating process without epitaxial regrowth, making the process significantly less expensive than conventional DFB fabrication. The devices are based on InGaAsSb/AlGaAsSb separate confinement heterostructures grown on GaSb by molecular beam epitaxy. DFB lasers were produced using a two step etch process. Narrow ridge waveguides were first defined by optical lithography and etched into the semiconductor. Lateral gratings were then defined on both sides of the ridge using electron-beam lithography and etched to produce the index-grating. Effective index modeling was used to optimize the ridge width, etch depths and the grating pitch to ensure single-lateral-mode operation and adequate coupling strength. The effective index method was further used to simulate the DFB laser emission spectrum, based on a transfer matrix model for light transmission through the periodic structure. The fabricated lasers exhibit single-mode operation which is tunable through the absorption features of the various target gases by adjustment of the drive current. In addition to the established open-path sensing applications, these devices have great potential for optoelectronic integrated gas sensors, making use of integrated photodetectors and possibly on-chip Si photonics waveguide structures.

  10. A fast mode decision algorithm for multiview auto-stereoscopic 3D video coding based on mode and disparity statistic analysis

    Science.gov (United States)

    Ding, Cong; Sang, Xinzhu; Zhao, Tianqi; Yan, Binbin; Leng, Junmin; Yuan, Jinhui; Zhang, Ying

    2012-11-01

    Multiview video coding (MVC) is essential for applications of the auto-stereoscopic three-dimensional displays. However, the computational complexity of MVC encoders is tremendously huge. Fast algorithms are very desirable for the practical applications of MVC. Based on joint early termination , the selection of inter-view prediction and the optimization of the process of Inter8×8 modes by comparison, a fast macroblock(MB) mode selection algorithm is presented. Comparing with the full mode decision in MVC, the experimental results show that the proposed algorithm can reduce up to 78.13% on average and maximum 90.21% encoding time with a little increase in bit rates and loss in PSNR.

  11. A semiconductor-based, frequency-stabilized mode-locked laser using a phase modulator and an intracavity etalon.

    Science.gov (United States)

    Davila-Rodriguez, Josue; Ozdur, Ibrahim; Williams, Charles; Delfyett, Peter J

    2010-12-15

    We report a frequency-stabilized semiconductor-based mode-locked laser that uses a phase modulator and an intracavity Fabry-Perot etalon for both active mode-locking and optical frequency stabilization. A twofold multiplication of the repetition frequency of the laser is inherently obtained in the process. The residual timing jitter of the mode-locked pulse train is 13 fs (1 Hz to 100 MHz), measured after regenerative frequency division of the photodetected pulse train.

  12. Filter based receive-side spatial compounding for veterinary ultrasound B-mode imaging.

    Science.gov (United States)

    Liu, Wen; Cheng, Yangjie; Liu, Dong C

    2014-01-01

    Veterinary ultrasound has been used in a large number of animal husbandry-related circumstances while many corresponding applications also call for the use of ultrasound in human patients. However, veterinary ultrasound images are affected by speckle, an interference pattern that can reduce the quality and contrast of ultrasound images. In this paper, a filter-based receive-side spatial compounding technique for veterinary ultrasound B-Mode imaging is used to create a compounded veterinary B-Mode image based on multiple looks. In particular, filtering in the lateral direction has been proved to be able to preserve the axial information in the sub-bands and to create decorrelation between sub-bands at the expense of some lateral resolution. A new method was proposed to obtain B-Mode IQ data by special veterinary ultrasonic probe. This approach is tested on 275 in-vivo swine. The effect is accomplished in real-time veterinary ultrasonic imaging with a measurable improvement of SNRe. Meanwhile, the speckle and electronic noise in the compounded image have been greatly reduced and smoothed in the visual result.

  13. Sliding mode disturbance observer-based adaptive integral backstepping control of a piezoelectric nano-manipulator

    Science.gov (United States)

    Zhang, Yangming; Yan, Peng

    2016-12-01

    This paper investigates a systematic modeling and control methodology for a multi-axis PZT (piezoelectric transducer) actuated servo stage supporting nano-manipulations. A sliding mode disturbance observer-based adaptive integral backstepping control method with an estimated inverse model compensation scheme is proposed to achieve ultra high precision tracking in the presence of the hysteresis nonlinearities, model uncertainties, and external disturbances. By introducing a time rate of the input signal, an enhanced rate-dependent Prandtl-Ishlinskii model is developed to describe the hysteresis behaviors, and its inverse is also constructed to mitigate their adverse effects. In particular, the corresponding inverse compensation error is analyzed and its boundedness is proven. Subsequently, the sliding mode disturbance observer-based adaptive integral backstepping controller is designed to guarantee the convergence of the tracking error, where the sliding mode disturbance observer can track the total disturbances in a finite time, while the integral action is incorporated into the adaptive backstepping design to improve the steady-state control accuracy. Finally, real time implementations of the proposed algorithm are applied on the PZT actuated servo system, where excellent tracking performance with tracking precision error around 6‰ for circular contour tracking is achieved in the experimental results.

  14. Current Sensor Fault Diagnosis Based on a Sliding Mode Observer for PMSM Driven Systems.

    Science.gov (United States)

    Huang, Gang; Luo, Yi-Ping; Zhang, Chang-Fan; Huang, Yi-Shan; Zhao, Kai-Hui

    2015-05-11

    This paper proposes a current sensor fault detection method based on a sliding mode observer for the torque closed-loop control system of interior permanent magnet synchronous motors. First, a sliding mode observer based on the extended flux linkage is built to simplify the motor model, which effectively eliminates the phenomenon of salient poles and the dependence on the direct axis inductance parameter, and can also be used for real-time calculation of feedback torque. Then a sliding mode current observer is constructed in αβ coordinates to generate the fault residuals of the phase current sensors. The method can accurately identify abrupt gain faults and slow-variation offset faults in real time in faulty sensors, and the generated residuals of the designed fault detection system are not affected by the unknown input, the structure of the observer, and the theoretical derivation and the stability proof process are concise and simple. The RT-LAB real-time simulation is used to build a simulation model of the hardware in the loop. The simulation and experimental results demonstrate the feasibility and effectiveness of the proposed method.

  15. Current Sensor Fault Diagnosis Based on a Sliding Mode Observer for PMSM Driven Systems

    Directory of Open Access Journals (Sweden)

    Gang Huang

    2015-05-01

    Full Text Available This paper proposes a current sensor fault detection method based on a sliding mode observer for the torque closed-loop control system of interior permanent magnet synchronous motors. First, a sliding mode observer based on the extended flux linkage is built to simplify the motor model, which effectively eliminates the phenomenon of salient poles and the dependence on the direct axis inductance parameter, and can also be used for real-time calculation of feedback torque. Then a sliding mode current observer is constructed in αβ coordinates to generate the fault residuals of the phase current sensors. The method can accurately identify abrupt gain faults and slow-variation offset faults in real time in faulty sensors, and the generated residuals of the designed fault detection system are not affected by the unknown input, the structure of the observer, and the theoretical derivation and the stability proof process are concise and simple. The RT-LAB real-time simulation is used to build a simulation model of the hardware in the loop. The simulation and experimental results demonstrate the feasibility and effectiveness of the proposed method.

  16. Determination of knock characteristics in spark ignition engines: an approach based on ensemble empirical mode decomposition

    Science.gov (United States)

    Li, Ning; Yang, Jianguo; Zhou, Rui; Liang, Caiping

    2016-04-01

    Knock is one of the major constraints to improve the performance and thermal efficiency of spark ignition (SI) engines. It can also result in severe permanent engine damage under certain operating conditions. Based on the ensemble empirical mode decomposition (EEMD), this paper proposes a new approach to determine the knock characteristics in SI engines. By adding a uniformly distributed and finite white Gaussian noise, the EEMD can preserve signal continuity in different scales and therefore alleviates the mode-mixing problem occurring in the classic empirical mode decomposition (EMD). The feasibilities of applying the EEMD to detect the knock signatures of a test SI engine via the pressure signal measured from combustion chamber and the vibration signal measured from cylinder head are investigated. Experimental results show that the EEMD-based method is able to detect the knock signatures from both the pressure signal and vibration signal, even in initial stage of knock. Finally, by comparing the application results with those obtained by short-time Fourier transform (STFT), Wigner-Ville distribution (WVD) and discrete wavelet transform (DWT), the superiority of the EEMD method in determining knock characteristics is demonstrated.

  17. Adaptive Sliding Mode Control Method Based on Nonlinear Integral Sliding Surface for Agricultural Vehicle Steering Control

    Directory of Open Access Journals (Sweden)

    Taochang Li

    2014-01-01

    Full Text Available Automatic steering control is the key factor and essential condition in the realization of the automatic navigation control of agricultural vehicles. In order to get satisfactory steering control performance, an adaptive sliding mode control method based on a nonlinear integral sliding surface is proposed in this paper for agricultural vehicle steering control. First, the vehicle steering system is modeled as a second-order mathematic model; the system uncertainties and unmodeled dynamics as well as the external disturbances are regarded as the equivalent disturbances satisfying a certain boundary. Second, a transient process of the desired system response is constructed in each navigation control period. Based on the transient process, a nonlinear integral sliding surface is designed. Then the corresponding sliding mode control law is proposed to guarantee the fast response characteristics with no overshoot in the closed-loop steering control system. Meanwhile, the switching gain of sliding mode control is adaptively adjusted to alleviate the control input chattering by using the fuzzy control method. Finally, the effectiveness and the superiority of the proposed method are verified by a series of simulation and actual steering control experiments.

  18. Three-dimensional guidance law based on adaptive integral sliding mode control

    Institute of Scientific and Technical Information of China (English)

    Song Junhong; Song Shenmin

    2016-01-01

    For the terminal guidance problem of missiles intercepting maneuvering targets in the three-dimensional space, the design of guidance laws for non-decoupling three-dimensional engage-ment geometry is studied. Firstly, by introducing a finite time integral sliding mode manifold, a novel guidance law based on the integral sliding mode control is presented with the target acceler-ation as a known bounded external disturbance. Then, an improved adaptive guidance law based on the integral sliding mode control without the information of the upper bound on the target accel-eration is developed, where the upper bound of the target acceleration is estimated online by a designed adaptive law. The both presented guidance laws can make sure that the elevation angular rate of the line-of-sight and the azimuth angular rate of the line-of-sight converge to zero in finite time. In the end, the results of the guidance performance for the proposed guidance laws are pre-sented by numerical simulations. Although the designed guidance laws are developed for the con-stant speed missiles, the simulation results for the time-varying speed missiles are also shown to further confirm the designed guidance laws.

  19. The first estimates of global nucleation mode aerosol concentrations based on satellite measurements

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2011-11-01

    Full Text Available Atmospheric aerosols play a key role in the Earth's climate system by scattering and absorbing solar radiation and by acting as cloud condensation nuclei. Satellites are increasingly used to obtain information on properties of aerosol particles with a diameter larger than about 100 nm. However, new aerosol particles formed by nucleation are initially much smaller and grow into the optically active size range on time scales of many hours. In this paper we derive proxies, based on process understanding and ground-based observations, to determine the concentrations of these new particles and their spatial distribution using satellite data. The results are applied to provide seasonal variation of nucleation mode concentration. The proxies describe the concentration of nucleation mode particles over continents. The source rates are related to both regional nucleation and nucleation associated with more restricted sources. The global pattern of nucleation mode particle number concentration predicted by satellite data using our proxies is compared qualitatively against both observations and global model simulations.

  20. Web-based versus traditional paper questionnaires: a mixed-mode survey with a Nordic perspective.

    Science.gov (United States)

    Hohwü, Lena; Lyshol, Heidi; Gissler, Mika; Jonsson, Stefan Hrafn; Petzold, Max; Obel, Carsten

    2013-08-26

    Survey response rates have been declining over the past decade. The more widespread use of the Internet and Web-based technologies among potential health survey participants suggests that Web-based questionnaires may be an alternative to paper questionnaires in future epidemiological studies. To compare response rates in a population of parents by using 4 different modes of data collection for a questionnaire survey of which 1 involved a nonmonetary incentive. A random sample of 3148 parents of Danish children aged 2-17 years were invited to participate in the Danish part of the NordChild 2011 survey on their children's health and welfare. NordChild was conducted in 1984 and 1996 in collaboration with Finland, Iceland, Norway, and Sweden using mailed paper questionnaires only. In 2011, all countries used conventional paper versions only except Denmark where the parents were randomized into 4 groups: (1) 789 received a paper questionnaire only (paper), (2) 786 received the paper questionnaire and a log-in code to the Web-based questionnaire (paper/Web), (3) 787 received a log-in code to the Web-based questionnaire (Web), and (4) 786 received log-in details to the Web-based questionnaire and were given an incentive consisting of a chance to win a tablet computer (Web/tablet). In connection with the first reminder, the nonresponders in the paper, paper/Web, and Web groups were also present with the opportunity to win a tablet computer as a means of motivation. Descriptive analysis was performed using chi-square tests. Odds ratios were used to estimate differences in response rates between the 4 modes. In 2011, 1704 of 3148 (54.13%) respondents answered the Danish questionnaire. The highest response rate was with the paper mode (n=443, 56.2%). The other groups had similar response rates: paper/Web (n=422, 53.7%), Web (n=420, 53.4%), and Web/tablet (n=419, 53.3%) modes. Compared to the paper mode, the odds for response rate in the paper/Web decreased by 9% (OR 0.91, 95

  1. Synchronizing chaotic dynamics with uncertainties based on a sliding mode control design.

    Science.gov (United States)

    Yang, Tao; Shao, Hui He

    2002-04-01

    The synchronization of two chaotic systems with uncertainties is studied in this paper. A feedback controller is provided based on a sliding mode control design. A kind of extended state observer is used to compensate for the systems' uncertainties, such as the structure difference or parameter mismatching, using only the available synchronizing error. Then the feedback controller becomes physically realizable based on the states of the observer, and can be used to synchronize two continuous chaotic systems. Illustrative examples of the synchronization of Duffing and Van der Pol oscillators as well as two Lorenz systems with parameter mismatching are proposed to show the effectiveness of this method.

  2. Edge-preserving Intra mode for efficient depth map coding based on H.264/AVC

    DEFF Research Database (Denmark)

    Zamarin, Marco; Forchhammer, Søren

    2014-01-01

    Depth-image-based-rendering (DIBR) algorithms for 3D video communication systems based on the “multi-view video plus depth” format are very sensitive to the accuracy of depth information. Specifically, edge regions in the depth data should be preserved in the coding/decoding process to ensure good...... targeted to depth macroblocks with arbitrarily shaped edges, which are typically not predicted well by the standard Intra modes of H.264/AVC and result in high rate–distortion costs. The proposed algorithm segments edge macroblocks into two regions each approximated by a flat surface. A binary mask...... texture plus depth rate–distortion performance....

  3. A new automatic alignment technology for single mode fiber-waveguide based on improved genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu; CHEN Zhuang-zhuang; LI Ya-juan; DUAN Jian

    2009-01-01

    A novel automatic alignment algorithm of single mode fiber-waveguide based on improved genetic algorithm is proposed. The genetic searching is based on the dynamic crossover operator and the adaptive mutation operator to solve the premature convergence of simple genetic algorithm The improved genetic algorithm combines with hill-climbing method and pattern searching algorithm, to solve low precision of simple genetic algorithm in later searching. The simulation results indicate that the improved genetic algorithm can rise the alignment precision and reach the coupling loss of 0.01 dB when platform moves near 207 space points averagely.

  4. Drag-based composite super-twisting sliding mode control law design for Mars entry guidance

    Science.gov (United States)

    Zhao, Zhenhua; Yang, Jun; Li, Shihua; Guo, Lei

    2016-06-01

    In this paper, the drag-based trajectory tracking guidance problem is investigated for Mars entry vehicle subject to uncertainties. A composite super twisting sliding mode control method based on finite-time disturbance observer is proposed for guidance law design. The proposed controller not only eliminates the effects of matched and mismatched disturbances due to uncertainties of atmospheric models and vehicle aerodynamics but also guarantees the continuity of control action. Numerical simulations are carried out on the basis of Mars Science Laboratory mission, where the results show that the proposed methods can improve the Mars entry guidance precision as compared with some existing guidance methods including PID and ADRC.

  5. Perfect forward secure identity-based authenticated key agreement protocol in the escrow mode

    Institute of Scientific and Technical Information of China (English)

    WANG ShengBao; CAO ZhenFu; CHENG ZhaoHui; CHOO Kim-KwangRaymond

    2009-01-01

    The majority of existing escrowable identity-based key agreement protocols only provide partial forward secrecy. Such protocols are, arguably, not suitable for many real-word applications, as the latter tends to require a stronger sense of forward secrecy-perfect forward secrecy. In this paper, we propose an efficient perfect forward-secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Bilinear Diffie-Hellman (GBDH) problem.

  6. Control Algorithm of Electric Vehicle in Coasting Mode Based on Driving Feeling

    Institute of Scientific and Technical Information of China (English)

    SUN Daxu; LAN Fengchong; ZHOU Yunjiao; CHEN Jiqing

    2015-01-01

    Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine (ICE), and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode. However, the electric vehicle (EV) does not have this feature in the coasting mode due to the relatively small inertia of the driving motor, so it will cause the driver cannot obtaln the similar driving feeling to that of the conventional vehicle, and even a traffic accident may occur if the driver cannot immediately adapt to the changes. In this paper, the coasting control for EV is researched based on the driving feeling. A conventional vehicle equipped with continuously variable transmission (CVT) is taken as the reference vehicle, and the combined simulation model of EV is established based on AVL CRUISE and MATLAB/Simulink. The torque characteristic of the CVT output shaft is measured in coasting mode, and the data are smoothed and fitted to a polynomial curve. For the EV in coasting mode, if the state of charge (SOC) of the battery is below 95%, the polynomial curve is used as the control target for the torque characteristic of the driving motor, otherwise, the required torque is replaced by hydraulic braking torque to keep the same deceleration. The co-simulation of Matlab/Simulink/Stateflow and AVL CRUISE, as well as the hardware-in-loop experiment combined with dSPACE are carried out to verify the effectiveness and the real-time performance of the control algorithm. The results show that the EV with coasting braking control system has similar driving feeling to that of the reference vehicle, meanwhile, the battery SOC can be increased by 0.036%and 0.021%in the initial speed of 100 km/h and 50 km/h, respectively. The proposed control algorithm for EV is beneficial to improve the driving feeling in coasting mode, and it also makes the EV has the assistant braking function.

  7. Parameter Identification and Synchronization of Uncertain Chaotic Systems Based on Sliding Mode Observer

    Directory of Open Access Journals (Sweden)

    Li-lian Huang

    2013-01-01

    Full Text Available The synchronization of nonlinear uncertain chaotic systems is investigated. We propose a sliding mode state observer scheme which combines the sliding mode control with observer theory and apply it into the uncertain chaotic system with unknown parameters and bounded interference. Based on Lyapunov stability theory, the constraints of synchronization and proof are given. This method not only can realize the synchronization of chaotic systems, but also identify the unknown parameters and obtain the correct parameter estimation. Otherwise, the synchronization of chaotic systems with unknown parameters and bounded external disturbances is robust by the design of the sliding surface. Finally, numerical simulations on Liu chaotic system with unknown parameters and disturbances are carried out. Simulation results show that this synchronization and parameter identification has been totally achieved and the effectiveness is verified very well.

  8. Implementation of fuzzy-sliding mode based control of a grid connected photovoltaic system.

    Science.gov (United States)

    Menadi, Abdelkrim; Abdeddaim, Sabrina; Ghamri, Ahmed; Betka, Achour

    2015-09-01

    The present work describes an optimal operation of a small scale photovoltaic system connected to a micro-grid, based on both sliding mode and fuzzy logic control. Real time implementation is done through a dSPACE 1104 single board, controlling a boost chopper on the PV array side and a voltage source inverter (VSI) on the grid side. The sliding mode controller tracks permanently the maximum power of the PV array regardless of atmospheric condition variations, while The fuzzy logic controller (FLC) regulates the DC-link voltage, and ensures via current control of the VSI a quasi-total transit of the extracted PV power to the grid under a unity power factor operation. Simulation results, carried out via Matlab-Simulink package were approved through experiment, showing the effectiveness of the proposed control techniques.

  9. A Human ECG Identification System Based on Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Yi Luo

    2013-05-01

    Full Text Available In this paper, a human electrocardiogram (ECG identification system based on ensemble empirical mode decomposition (EEMD is designed. A robust preprocessing method comprising noise elimination, heartbeat normalization and quality measurement is proposed to eliminate the effects of noise and heart rate variability. The system is independent of the heart rate. The ECG signal is decomposed into a number of intrinsic mode functions (IMFs and Welch spectral analysis is used to extract the significant heartbeat signal features. Principal component analysis is used reduce the dimensionality of the feature space, and the K-nearest neighbors (K-NN method is applied as the classifier tool. The proposed human ECG identification system was tested on standard MIT-BIH ECG databases: the ST change database, the long-term ST database, and the PTB database. The system achieved an identification accuracy of 95% for 90 subjects, demonstrating the effectiveness of the proposed method in terms of accuracy and robustness.

  10. Multi-faults decoupling on turbo-expander using differential-based ensemble empirical mode decomposition

    Science.gov (United States)

    Li, Hongguang; Li, Ming; Li, Cheng; Li, Fucai; Meng, Guang

    2017-09-01

    This paper dedicates on the multi-faults decoupling of turbo-expander rotor system using Differential-based Ensemble Empirical Mode Decomposition (DEEMD). DEEMD is an improved version of DEMD to resolve the imperfection of mode mixing. The nonlinear behaviors of the turbo-expander considering temperature gradient with crack, rub-impact and pedestal looseness faults are investigated respectively, so that the baseline for the multi-faults decoupling can be established. DEEMD is then utilized on the vibration signals of the rotor system with coupling faults acquired by numerical simulation, and the results indicate that DEEMD can successfully decouple the coupling faults, which is more efficient than EEMD. DEEMD is also applied on the vibration signal of the misalignment coupling with rub-impact fault obtained during the adjustment of the experimental system. The conclusion shows that DEEMD can decompose the practical multi-faults signal and the industrial prospect of DEEMD is verified as well.

  11. A Modified Model of Failure Mode and Effects Analysis Based on Generalized Evidence Theory

    Directory of Open Access Journals (Sweden)

    Deyun Zhou

    2016-01-01

    Full Text Available Due to the incomplete knowledge, how to handle the uncertain risk factors in failure mode and effects analysis (FMEA is still an open issue. This paper proposes a new generalized evidential FMEA (GEFMEA model to handle the uncertain risk factor, which may not be included in the conventional FMEA model. In GEFMEA, not only the conventional risk factors, the occurrence, severity, and detectability of the failure mode, but also the other incomplete risk factors are taken into consideration. In addition, the relative importance among all these risk factors is well addressed in the proposed method. GEFMEA is based on the generalized evidence theory, which is efficient in handling incomplete information in the open world. The efficiency and some merit of the proposed method are verified by the numerical example and a real case study on aircraft turbine rotor blades.

  12. Coupled multiple-mode theory for s± pairing mechanism in iron based superconductors.

    Science.gov (United States)

    Kiselev, M N; Efremov, D V; Drechsler, S L; van den Brink, Jeroen; Kikoin, K

    2016-11-29

    We investigate the interplay between the magnetic and the superconducting degrees of freedom in unconventional multi-band superconductors such as iron pnictides. For this purpose a dynamical mode-mode coupling theory is developed based on the coupled Bethe-Salpeter equations. In order to investigate the region of the phase diagram not too far from the tetracritical point where the magnetic spin density wave, (SDW) and superconducting (SC) transition temperatures coincide, we also construct a Ginzburg-Landau functional including both SC and SDW fluctuations in a critical region above the transition temperatures. The fluctuation corrections tend to suppress the magnetic transition, but in the superconducting channel the intraband and interband contribution of the fluctuations nearly compensate each other.

  13. Mode-dependent templates and scan order for H.264/AVC-based intra lossless coding.

    Science.gov (United States)

    Gu, Zhouye; Lin, Weisi; Lee, Bu-Sung; Lau, Chiew Tong; Sun, Ming-Ting

    2012-09-01

    In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.

  14. A Novel Acoustic Emission Fiber Optic Sensor Based on a Single Mode Optical Fiber Coupler

    Institute of Scientific and Technical Information of China (English)

    CHEN Rongsheng; LIAO Yanbiao; ZHENG Gangtie; LIU Tongyu; Gerard Franklyn Fernando

    2001-01-01

    This paper reports, for the first time, on the use of a fused-taper single mode optical fiber coupler as a sensing element for the detection of acoustic emission (AE) and ultrasound. When an acoustic wave impinges on the mode-coupling region of a coupler, the coupling coefficient is modulated via the photo-elastic effect. Therefore, the transfer function of the coupler is modulated by an acoustic wave. The sensitivity of the sensor at 140 kHz was approximately 5.2 mV/Pa and the noise floor was 1 Pa. The bandwidth of the sensor was up to several hundred kHz. This AE sensor exhibits significant advantage compared with interferometer-based AE sensors.

  15. Refractive index insensitive temperature sensor based on waist-enlarged few mode fiber bitapers

    Science.gov (United States)

    Liu, Qiang; Wang, Si-wen; Fu, Xing-hu; Fu, Guang-wei; Jin, Wa; Bi, Wei-hong

    2017-01-01

    A refractive index insensitive temperature sensor based on waist-enlarged few mode fiber (FMF) bitapers is presented. The first section of FMF is spliced between two single-mode fibers. In fusion process, the waist-enlarged FMF bitapers can be obtained by large current discharging repeatedly. The refractive index and temperature sensing mechanisms are analyzed. For the sensors with different sizes, the refractive index and temperature experiments have been performed. The results show that in the refractive index ranges of 1.335 0—1.346 6 and 1.348 2—1.419 3, the refractive index insensitivity is verified. In a temperature range of 31.9—90 °C, the sensor sensitivity can be up to 85.57 pm/°C. In addition, it has a compact structure. Therefore, the sensor can avoid the cross sensitivity for measuring the refractive index and temperature simultaneously.

  16. Refractive index sensors based on the fused tapered special multi-mode fiber

    Science.gov (United States)

    Fu, Xing-hu; Xiu, Yan-li; Liu, Qin; Xie, Hai-yang; Yang, Chuan-qing; Zhang, Shun-yang; Fu, Guang-wei; Bi, Wei-hong

    2016-01-01

    In this paper, a novel refractive index (RI) sensor is proposed based on the fused tapered special multi-mode fiber (SMMF). Firstly, a section of SMMF is spliced between two single-mode fibers (SMFs). Then, the SMMF is processed by a fused tapering machine, and a tapered fiber structure is fabricated. Finally, a fused tapered SMMF sensor is obtained for measuring external RI. The RI sensing mechanism of tapered SMMF sensor is analyzed in detail. For different fused tapering lengths, the experimental results show that the RI sensitivity can be up to 444.517 81 nm/RIU in the RI range of 1.334 9—1.347 0. The RI sensitivity is increased with the increase of fused tapering length. Moreover, it has many advantages, including high sensitivity, compact structure, fast response and wide application range. So it can be used to measure the solution concentration in the fields of biochemistry, health care and food processing.

  17. Signal classification method based on data mining for multi-mode radar

    Institute of Scientific and Technical Information of China (English)

    Qiang Guo; Pulong Nan; Jian Wan

    2016-01-01

    For the multi-mode radar working in the modern elec-tronic battlefield, different working states of one single radar are prone to being classified as multiple emitters when adopting traditional classification methods to process intercepted signals, which has a negative effect on signal classification. A classification method based on spatial data mining is presented to address the above chal enge. Inspired by the idea of spatial data mining, the classification method applies nuclear field to depicting the distribu-tion information of pulse samples in feature space, and digs out the hidden cluster information by analyzing distribution characteristics. In addition, a membership-degree criterion to quantify the correla-tion among al classes is established, which ensures classification accuracy of signal samples. Numerical experiments show that the presented method can effectively prevent different working states of multi-mode emitter from being classified as several emitters, and achieve higher classification accuracy.

  18. Emulation and design of terahertz reflection-mode confocal scanning microscopy based on virtual pinhole

    Science.gov (United States)

    Yang, Yong-fa; Li, Qi

    2014-12-01

    In the practical application of terahertz reflection-mode confocal scanning microscopy, the size of detector pinhole is an important factor that determines the performance of spatial resolution characteristic of the microscopic system. However, the use of physical pinhole brings some inconvenience to the experiment and the adjustment error has a great influence on the experiment result. Through reasonably selecting the parameter of matrix detector virtual pinhole (VPH), it can efficiently approximate the physical pinhole. By using this approach, the difficulty of experimental calibration is reduced significantly. In this article, an imaging scheme of terahertz reflection-mode confocal scanning microscopy that is based on the matrix detector VPH is put forward. The influence of detector pinhole size on the axial resolution of confocal scanning microscopy is emulated and analyzed. Then, the parameter of VPH is emulated when the best axial imaging performance is reached.

  19. Breech at term--mode of delivery? A register-based study

    DEFF Research Database (Denmark)

    1995-01-01

    . Register-based cohort study of all (n = 15718) singleton term breech deliveries of non-malformed infants in Denmark 1982-1990. Process and outcome measures: mode of delivery, gestational age, birth weight, congenital malformations, intrapartum death, Apgar scores and early neonatal death. RESULTS. A total...... of 3247 (20.7%) term infants were delivered vaginally, 7106 (45.3%) by elective and 5356 (34.1%) by emergency cesarean section. Infants delivered vaginally and by emergency cesarean section had significantly higher rates of mortality (intrapartum and early neonatal death) and morbidity (low Apgar scores......BACKGROUND. The present study was designed to determine neonatal mortality and morbidity in non-malformed singleton term infants delivered in breech presentation and identify a possible correlation between outcome on the one hand and mode of delivery, parity and birth weight on the other. METHODS...

  20. Fast and Adaptive Bidimensional Empirical Mode Decomposition Using Order-Statistics Filter Based Envelope Estimation

    Directory of Open Access Journals (Sweden)

    Jesmin F. Khan

    2008-08-01

    Full Text Available A novel approach for bidimensional empirical mode decomposition (BEMD is proposed in this paper. BEMD decomposes an image into multiple hierarchical components known as bidimensional intrinsic mode functions (BIMFs. In each iteration of the process, two-dimensional (2D interpolation is applied to a set of local maxima (minima points to form the upper (lower envelope. But, 2D scattered data interpolation methods cause huge computation time and other artifacts in the decomposition. This paper suggests a simple, but effective, method of envelope estimation that replaces the surface interpolation. In this method, order statistics filters are used to get the upper and lower envelopes, where filter size is derived from the data. Based on the properties of the proposed approach, it is considered as fast and adaptive BEMD (FABEMD. Simulation results demonstrate that FABEMD is not only faster and adaptive, but also outperforms the original BEMD in terms of the quality of the BIMFs.

  1. A surface plasmon resonance sensor based on a single mode D-shape polymer optical fiber

    Science.gov (United States)

    Gasior, Katarzyna; Martynkien, Tadeusz; Napiorkowski, Maciej; Zolnacz, Kinga; Mergo, Pawel; Urbanczyk, Waclaw

    2017-02-01

    For the first time to our knowledge, we report a successful fabrication of surface plasmon resonance (SPR) sensors in a specially developed single-mode birefringent polymer D-shape fiber with a core made of PMMA/PS copolymer. A small distance between the core and the cladding boundary allows to deposit a gold layer directly onto the flat fiber surface, which significantly simplifies the sensors fabrication process. The developed SPR sensor exhibits a sensitivity of 2765 nm RIU-1 for the refractive index of external medium equal to 1.410, which is similar to the sensitivity of the SPR sensors based on conventional side-polished single-mode silica fibers. Using the finite element method, we also numerically studied the sensor performance. The sensor characteristics obtained in the simulations are in a relatively good agreement with the experimental results.

  2. Riemann Liouvelle Fractional Integral based Empirical Mode Decomposition for ECG Denoising.

    Science.gov (United States)

    Jain, Shweta; Bajaj, Varun; Kumar, Anil

    2017-09-18

    Electrocardiograph (ECG) denoising is the most important step in diagnosis of heart related diseases, as the diagnosis gets influenced with noises. In this paper, a new method for ECG denoising is proposed, which incorporates empirical mode decomposition algorithm and Riemann Liouvelle (RL) fractional integral filtering. In the proposed method, noisy ECG signal is decomposed into its intrinsic mode functions (IMFs); from which noisy IMFs are identified by proposed noisy-IMFs identification methodology. RL fractional integral filtering is applied on noisy IMFs to get denoised IMFs; ECG signal is reconstructed with denoised IMFs and remaining signal dominant IMFs to obtain noise-free ECG signal. Proposed methodology is tested with MIT-BIH arrhythmia database. Its performance, in terms of signal to noise ratio (SNR) and mean square error (MSE), is compared with other related fractional integral and EMD based ECG denoising methods. The obtained results by proposed method prove that the proposed method gives efficient noise removal performance.

  3. Signal enhancement based on complex curvelet transform and complementary ensemble empirical mode decomposition

    Science.gov (United States)

    Dong, Lieqian; Wang, Deying; Zhang, Yimeng; Zhou, Datong

    2017-09-01

    Signal enhancement is a necessary step in seismic data processing. In this paper we utilize the complementary ensemble empirical mode decomposition (CEEMD) and complex curvelet transform (CCT) methods to separate signal from random noise further to improve the signal to noise (S/N) ratio. Firstly, the original data with noise is decomposed into a series of intrinsic mode function (IMF) profiles with the aid of CEEMD. Then the IMFs with noise are transformed into CCT domain. By choosing different thresholds which are based on the noise level difference of each IMF profile, the noise in original data can be suppressed. Finally, we illustrate the effectiveness of the approach by simulated and field datasets.

  4. Combining BRITE and ground-based photometry for the Beta Cephei star Nu Eridani: impact on photometric pulsation mode identification and detection of several g modes

    CERN Document Server

    Handler, G; Popowicz, A; Pigulski, A; Kuschnig, R; Zoclonska, E; Moffat, A F J; Weiss, W W; Grant, C C; Pablo, H; Whittaker, G N; Rucinski, S M; Ramiaramanantsoa, T; Zwintz, K; Wade, G A

    2016-01-01

    We report a simultaneous ground and space-based photometric study of the Beta Cephei star Nu Eridani. Half a year of observations have been obtained by four of the five satellites constituting BRITE-Constellation, supplemented with ground-based photoelectric photometry. We show that carefully combining the two data sets virtually eliminates the aliasing problem that often hampers time-series analyses. We detect 40 periodic signals intrinsic to the star in the light curves. Despite a lower detection limit we do not recover all the pressure and mixed modes previously reported in the literature, but we newly detect six additional gravity modes. This behaviour is a consequence of temporal changes in the pulsation amplitudes that we also detected for some of the p modes. We point out that the dependence of theoretically predicted pulsation amplitude on wavelength is steeper in visual passbands than those observationally measured, to the extent that the three dominant pulsation modes of Nu Eridani would be incorrec...

  5. Combining BRITE and ground-based photometry for the β Cephei star ν Eridani: impact on photometric pulsation mode identification and detection of several g modes

    Science.gov (United States)

    Handler, G.; Rybicka, M.; Popowicz, A.; Pigulski, A.; Kuschnig, R.; Zocłońska, E.; Moffat, A. F. J.; Weiss, W. W.; Grant, C. C.; Pablo, H.; Whittaker, G. N.; Ruciński, S. M.; Ramiaramanantsoa, T.; Zwintz, K.; Wade, G. A.

    2017-01-01

    We report a simultaneous ground- and space-based photometric study of the β Cephei star ν Eridani. Half a year of observations have been obtained by four of the five satellites constituting BRITE-Constellation, supplemented with ground-based photoelectric photometry. We show that carefully combining the two data sets virtually eliminates the aliasing problem that often hampers time series analyses. We detect 40 periodic signals intrinsic to the star in the light curves. Despite a lower detection limit, we do not recover all the pressure and mixed modes previously reported in the literature, but we newly detect six additional gravity modes. This behaviour is a consequence of temporal changes in the pulsation amplitudes that we also detected for some of the p modes. We point out that the dependence of theoretically predicted pulsation amplitude on wavelength is steeper in visual passbands than those observationally measured, to the extent that three dominant pulsation modes of ν Eridani would be incorrectly identified using data in optical filters only. We discuss possible reasons for this discrepancy.

  6. Combining BRITE and ground-based photometry for the β Cephei star ν Eridani: impact on photometric pulsation mode identification and detection of several g modes

    Science.gov (United States)

    Handler, G.; Rybicka, M.; Popowicz, A.; Pigulski, A.; Kuschnig, R.; Zocłońska, E.; Moffat, A. F. J.; Weiss, W. W.; Grant, C. C.; Pablo, H.; Whittaker, G. N.; Ruciński, S. M.; Ramiaramanantsoa, T.; Zwintz, K.; Wade, G. A.

    2016-10-01

    We report a simultaneous ground and space-based photometric study of the β Cephei star ν Eridani. Half a year of observations have been obtained by four of the five satellites constituting BRITE-Constellation, supplemented with ground-based photoelectric photometry. We show that carefully combining the two data sets virtually eliminates the aliasing problem that often hampers time-series analyses. We detect 40 periodic signals intrinsic to the star in the light curves. Despite a lower detection limit we do not recover all the pressure and mixed modes previously reported in the literature, but we newly detect six additional gravity modes. This behaviour is a consequence of temporal changes in the pulsation amplitudes that we also detected for some of the p modes. We point out that the dependence of theoretically predicted pulsation amplitude on wavelength is steeper in visual passbands than those observationally measured, to the extent that the three dominant pulsation modes of ν Eridani would be incorrectly identified using data in optical filters only. We discuss possible reasons for this discrepancy.

  7. The Comparison of Solitary and Collaborative Modes of Game-Based Learning on Students' Science Learning and Motivation

    Science.gov (United States)

    Chen, Ching-Huei; Wang, Kuan-Chieh; Lin, Yu-Hsuan

    2015-01-01

    In this study, we investigated and compared solitary and collaborative modes of game-based learning in promoting students' science learning and motivation. A total of fifty seventh grade students participated in this study. The results showed that students who played in a solitary or collaborative mode demonstrated improvement in learning…

  8. The Second Order Guided Modes Based on Photonic Bandgap Effects in Air/Glass Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    YAO Lei; LOU Shu-Qin; JIAN Shui-Sheng

    2009-01-01

    We introduce a defect site in the periodic structure of a photonic bandgap fiber,to confine and guide the second order mode by photonic bandgap effects.Based on a high air-filling fraction photonic crystal cladding structure,a simplified model with an equivalent air cladding was proposed to explore and analyze the properties of this second order guided mode.

  9. Passively mode-locked fiber laser based on polarization rotation in a multiple-quantum-well waveguide.

    Science.gov (United States)

    Okhotnikov, O G; Salcedo, J R

    1995-01-01

    We give experimental evidence for a new type of mode-locking mechanism for Er-doped fiber lasers based on polarization evolution in an intracavity multiple-quantum-well waveguide. Experiments indicate that anisotropic properties of waveguides can continuously start the mode-locking process.

  10. The Comparison of Solitary and Collaborative Modes of Game-Based Learning on Students' Science Learning and Motivation

    Science.gov (United States)

    Chen, Ching-Huei; Wang, Kuan-Chieh; Lin, Yu-Hsuan

    2015-01-01

    In this study, we investigated and compared solitary and collaborative modes of game-based learning in promoting students' science learning and motivation. A total of fifty seventh grade students participated in this study. The results showed that students who played in a solitary or collaborative mode demonstrated improvement in learning…

  11. Second-order sliding mode control for DFIG-based wind turbines fault ride-through capability enhancement.

    Science.gov (United States)

    Benbouzid, Mohamed; Beltran, Brice; Amirat, Yassine; Yao, Gang; Han, Jingang; Mangel, Hervé

    2014-05-01

    This paper deals with the fault ride-through capability assessment of a doubly fed induction generator-based wind turbine using a high-order sliding mode control. Indeed, it has been recently suggested that sliding mode control is a solution of choice to the fault ride-through problem. In this context, this paper proposes a second-order sliding mode as an improved solution that handle the classical sliding mode chattering problem. Indeed, the main and attractive features of high-order sliding modes are robustness against external disturbances, the grids faults in particular, and chattering-free behavior (no extra mechanical stress on the wind turbine drive train). Simulations using the NREL FAST code on a 1.5-MW wind turbine are carried out to evaluate ride-through performance of the proposed high-order sliding mode control strategy in case of grid frequency variations and unbalanced voltage sags.

  12. Two modified discrete PID-based sliding mode controllers for piezoelectric actuators

    Science.gov (United States)

    Cao, Y.; Chen, X. B.

    2014-01-01

    Hysteresis is a nonlinear effect that can result in the degraded performance of piezoelectric actuators (PEAs). To counteract the effect, several control methods have been developed and reported in the literature. One promising method for compensation is the use of a proportional-integral-derivative (PID)-based sliding mode control (SMC), in which the PEA hysteresis is treated as an unknown disturbance to the PEA input. If the hysteresis can be modelled or partially modelled, the integration of the hysteresis models into the control schemes may lead to further improved performance. On this philosophy, this paper presents the development of two modified discrete PID-based sliding mode controllers (PID-SMCs) for the PEAs, namely an inversion-based PID-SMC and a disturbance-observer (DOB)-based PID-SMC, in which the PEA hysteresis is predicted or partially predicted through the use of existing models for the PEA hysteresis. Experiments were performed to verify the effectiveness of the proposed control schemes. The results were compared to those of the nominal PID-SMC. By employing the inversion hysteresis and the DOB, the PEA performance was greatly improved.

  13. Travel Mode Detection Based on Neural Networks and Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Guangnian Xiao

    2015-08-01

    Full Text Available The collection of massive Global Positioning System (GPS data from travel surveys has increased exponentially worldwide since the 1990s. A number of methods, which range from rule-based to advanced classification approaches, have been applied to detect travel modes from GPS positioning data collected in travel surveys based on GPS-enabled smartphones or dedicated GPS devices. Among these approaches, neural networks (NNs are widely adopted because they can extract subtle information from training data that cannot be directly obtained by human or other analysis techniques. However, traditional NNs, which are generally trained by back-propagation algorithms, are likely to be trapped in local optimum. Therefore, particle swarm optimization (PSO is introduced to train the NNs. The resulting PSO-NNs are employed to distinguish among four travel modes (walk, bike, bus, and car with GPS positioning data collected through a smartphone-based travel survey. As a result, 95.81% of samples are correctly flagged for the training set, while 94.44% are correctly identified for the test set. Results from this study indicate that smartphone-based travel surveys provide an opportunity to supplement traditional travel surveys.

  14. Advanced Shock Position Control for Mode Transition in a Turbine Based Combined Cycle Engine Inlet Model

    Science.gov (United States)

    Csank, Jeffrey T.; Stueber, Thomas J.

    2013-01-01

    A dual flow-path inlet system is being tested to evaluate methodologies for a Turbine Based Combined Cycle (TBCC) propulsion system to perform a controlled inlet mode transition. Prior to experimental testing, simulation models are used to test, debug, and validate potential control algorithms. One simulation package being used for testing is the High Mach Transient Engine Cycle Code simulation, known as HiTECC. This paper discusses the closed loop control system, which utilizes a shock location sensor to improve inlet performance and operability. Even though the shock location feedback has a coarse resolution, the feedback allows for a reduction in steady state error and, in some cases, better performance than with previous proposed pressure ratio based methods. This paper demonstrates the design and benefit with the implementation of a proportional-integral controller, an H-Infinity based controller, and a disturbance observer based controller.

  15. Game theory-based mode cooperative selection mechanism for device-to-device visible light communication

    Science.gov (United States)

    Liu, Yuxin; Huang, Zhitong; Li, Wei; Ji, Yuefeng

    2016-03-01

    Various patterns of device-to-device (D2D) communication, from Bluetooth to Wi-Fi Direct, are emerging due to the increasing requirements of information sharing between mobile terminals. This paper presents an innovative pattern named device-to-device visible light communication (D2D-VLC) to alleviate the growing traffic problem. However, the occlusion problem is a difficulty in D2D-VLC. This paper proposes a game theory-based solution in which the best-response dynamics and best-response strategies are used to realize a mode-cooperative selection mechanism. This mechanism uses system capacity as the utility function to optimize system performance and selects the optimal communication mode for each active user from three candidate modes. Moreover, the simulation and experimental results show that the mechanism can attain a significant improvement in terms of effectiveness and energy saving compared with the cases where the users communicate via only the fixed transceivers (light-emitting diode and photo diode) or via only D2D.

  16. Online Adaptive Error Compensation SVM-Based Sliding Mode Control of an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Kaijia Xue

    2016-01-01

    Full Text Available Unmanned Aerial Vehicle (UAV is a nonlinear dynamic system with uncertainties and noises. Therefore, an appropriate control system has an obligation to ensure the stabilization and navigation of UAV. This paper mainly discusses the control problem of quad-rotor UAV system, which is influenced by unknown parameters and noises. Besides, a sliding mode control based on online adaptive error compensation support vector machine (SVM is proposed for stabilizing quad-rotor UAV system. Sliding mode controller is established through analyzing quad-rotor dynamics model in which the unknown parameters are computed by offline SVM. During this process, the online adaptive error compensation SVM method is applied in this paper. As modeling errors and noises both exist in the process of flight, the offline SVM one-time mode cannot predict the uncertainties and noises accurately. The control law is adjusted in real-time by introducing new training sample data to online adaptive SVM in the control process, so that the stability and robustness of flight are ensured. It can be demonstrated through the simulation experiments that the UAV that joined online adaptive SVM can track the changing path faster according to its dynamic model. Consequently, the proposed method that is proved has the better control effect in the UAV system.

  17. Quantitative analysis of multiple components based on liquid chromatography with mass spectrometry in full scan mode.

    Science.gov (United States)

    Xu, Min Li; Li, Bao Qiong; Wang, Xue; Chen, Jing; Zhai, Hong Lin

    2016-08-01

    Although liquid chromatography with mass spectrometry in full scan mode can obtain all the signals simultaneously in a large range and low cost, it is rarely used in quantitative analysis due to several problems such as chromatographic drifts and peak overlap. In this paper, we propose a Tchebichef moment method for the simultaneous quantitative analysis of three active compounds in Qingrejiedu oral liquid based on three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry. After the Tchebichef moments were calculated directly from the spectra, the quantitative linear models for three active compounds were established by stepwise regression. All the correlation coefficients were more than 0.9978. The limits of detection and limits of quantitation were less than 0.11 and 0.49 μg/mL, respectively. The intra- and interday precisions were less than 6.54 and 9.47%, while the recovery ranged from 102.56 to 112.15%. Owing to the advantages of multi-resolution and inherent invariance properties, Tchebichef moments could provide favorable results even in the situation of peaks shifting and overlapping, unknown interferences and noise signals, so it could be applied to the analysis of three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry.

  18. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan;

    2014-01-01

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due...

  19. Chattering Suppression for DSP Based Sliding Mode Current Control of PM DC Drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus

    2009-01-01

    This paper investigates several chattering suppression methods for DSP based implementation of sliding mode control (SMC). It concentrates on the ‘equivalent-control-dependent' and ‘state-dependent' gain adjustment methods proposed in recent theoretical studies, and tests the effectiveness...... performed separately, and so various combinations of these methods are tested to find the best solution for chattering elimination. Discontinuous control signal averaging, which is a common chattering reduction technique, is made possible while the system is online by the use of a tunable low-pass filter...

  20. Dynamic optimum dead time in piezoelectric transformer-based switch-mode power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Andersen, Thomas; Andersen, Michael A. E.;

    2016-01-01

    Soft switching is required to attain high efficiency in high-frequency power converters. Piezoelectric transformerbased converters can benefit from soft switching in terms of significantly diminished switching losses and stresses. Adequate dead time is needed in order to deliver sufficient energy...... to charge and discharge the input capacitance of piezoelectric transformers in order to achieve zero-voltage switching. This paper proposes a method for detecting the optimum dead time in piezoelectric transformer-based switch-mode power supplies. The provision of sufficient dead time in every cycle...

  1. Accessibility of islands: towards a new geography based on transportation modes and choices

    Directory of Open Access Journals (Sweden)

    Sofia Karampela

    2014-11-01

    Full Text Available Accessibility is a multifaceted concept that expresses the case of access between two points in space. For islands, accessibility is a key quality, since isolation and small size considered as inherent characteristics of “islandness”. In this paper, we discuss differences between geographical distance and accessibility potential in the Greek Aegean, combining different transportation modal choice (ferries and airplanes with the use of an accessibility index that incorporates modes and frequency of connection and data of actual usage. The findings indicate that geographical distance is not determining accessibility and new geographies emerge based more on the availability of transport modal choices.

  2. Modeling of PV Systems Based on Inflection Points Technique Considering Reverse Mode

    Directory of Open Access Journals (Sweden)

    Bonie J. Restrepo-Cuestas

    2013-11-01

    Full Text Available This paper proposes a methodology for photovoltaic (PV systems modeling, considering their behavior in both direct and reverse operating mode and considering mismatching conditions. The proposed methodology is based on the inflection points technique with a linear approximation to model the bypass diode and a simplified PV model. The proposed mathematical model allows to evaluate the energetic performance of a PV system, exhibiting short simulation times in large PV systems. In addition, this methodology allows to estimate the condition of the modules affected by the partial shading since it is possible to know the power dissipated due to its operation at the second quadrant.

  3. Model-based Sliding Mode Controller of Anti-lock Braking System

    Science.gov (United States)

    Zheng, Lin; Luo, Yue-Gang; Kang, Jing; Shi, Zhan-Qun

    2016-05-01

    The anti-lock braking system (ABS) used in automobiles is used to prevent wheel from lockup and to maintain the steering ability and stability. The sliding mode controller is able to control nonlinear system steadily. In this research, a one-wheel dynamic model with ABS control is built up using model-based method. Using the sliding model controller, the simulation results by using Matlab/Simulink show qualified data compared with optimal slip rate. By using this method, the ABS brake efficiency is improved efficiently.

  4. The Outline Design of Students’ Schedule Management System Based on B/S Mode

    Directory of Open Access Journals (Sweden)

    Mi Lan

    2016-01-01

    Full Text Available This study is based on a preliminary outline design involved in the development of B/S mode of student schedule management system. It can provide the foundation and basis for the Panel’s later detailed design and coding, and also standardize the team development. Documents will be divided into various modules, and the functional requirements of corresponding module are raised; total class diagrams, class function definitions and the function of functions are obtained for reference of the later design.

  5. Mode-evolution-based coupler for high saturation power Ge-on-Si photodetectors.

    Science.gov (United States)

    Byrd, Matthew J; Timurdogan, Erman; Su, Zhan; Poulton, Christopher V; Fahrenkopf, Nicholas M; Leake, Gerald; Coolbaugh, Douglas D; Watts, Michael R

    2017-02-15

    We propose a mode-evolution-based coupler for high saturation power germanium-on-silicon photodetectors. This coupler uniformly illuminates the intrinsic germanium region of the detector, decreasing saturation effects, such as carrier screening, observed at high input powers. We demonstrate 70% more photocurrent generation (9.1-15.5 mA) and more than 40 times higher opto-electrical bandwidth (0.7-31 GHz) than conventional butt-coupled detectors under high-power illumination. The high-power and high-speed performance of the device, combined with the compactness of the coupling method, will enable new applications for integrated silicon photonics systems.

  6. Efficient Compression of Far Field Matrices in Multipole Algorithms based on Spherical Harmonics and Radiating Modes

    Directory of Open Access Journals (Sweden)

    A. Schroeder

    2012-09-01

    Full Text Available This paper proposes a compression of far field matrices in the fast multipole method and its multilevel extension for electromagnetic problems. The compression is based on a spherical harmonic representation of radiation patterns in conjunction with a radiating mode expression of the surface current. The method is applied to study near field effects and the far field of an antenna placed on a ship surface. Furthermore, the electromagnetic scattering of an electrically large plate is investigated. It is demonstrated, that the proposed technique leads to a significant memory saving, making multipole algorithms even more efficient without compromising the accuracy.

  7. Spatiotemporal chaos synchronization of an uncertain network based on sliding mode control

    Institute of Scientific and Technical Information of China (English)

    Lü Ling; Yu Miao; Wei Lin-Ling; Zhang Meng; Li Yu-Shan

    2012-01-01

    The sliding mode control method is used to study spatiotemporal chaos synchronization of an uncertain network.The method is extended from synchronization between two chaotic systems to the synchronization of complex network composed of N spatiotemporal chaotic systems.The sliding surface of the network and the control input are designed.Furthermore,the effectiveness of the method is analysed based on the stability theory. The Burgers equation with spatiotemporal chaos behavior is taken as an example to simulate the experiment.It is found that the synchronization performance of the network is very stable.

  8. Forecasting Electricity Market Risk Using Empirical Mode Decomposition (EMD—Based Multiscale Methodology

    Directory of Open Access Journals (Sweden)

    Kaijian He

    2016-11-01

    Full Text Available The electricity market has experienced an increasing level of deregulation and reform over the years. There is an increasing level of electricity price fluctuation, uncertainty, and risk exposure in the marketplace. Traditional risk measurement models based on the homogeneous and efficient market assumption no longer suffice, facing the increasing level of accuracy and reliability requirements. In this paper, we propose a new Empirical Mode Decomposition (EMD-based Value at Risk (VaR model to estimate the downside risk measure in the electricity market. The proposed model investigates and models the inherent multiscale market risk structure. The EMD model is introduced to decompose the electricity time series into several Intrinsic Mode Functions (IMF with distinct multiscale characteristics. The Exponential Weighted Moving Average (EWMA model is used to model the individual risk factors across different scales. Experimental results using different models in the Australian electricity markets show that EMD-EWMA models based on Student’s t distribution achieves the best performance, and outperforms the benchmark EWMA model significantly in terms of model reliability and predictive accuracy.

  9. Adaptive PI-Based Sliding Mode Control for Nanopositioning of Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Jin Li

    2014-01-01

    Full Text Available This paper proposes an adaptive proportion-integral (PI-based sliding mode control design (APISMC used for nanopositioning of piezoelectric actuators (PEAs. Nonlinearities, mainly hysteresis, can drastically degrade the system performance. As well as the model imperfection, hysteresis can be treated as uncertainties of the system. These uncertainties can be addressed by sliding mode control (SMC since SMC is promising for positioning and tracking control. To further improve the response speed, suppress chattering, and reduce the steady-state error, the adaptive PI-based SMC is employed to replace the discontinuous control. Actually, the adaptive PI-based SMC offers a fast convergence of the sliding surface. Further, another advantage of the proposed controller lies in that its implementation only requires the online tuning PI parameters without acquiring the knowledge of bounds on system uncertainties. A linear second-order system is utilized as the estimated model to compensate for the process nonlinearity and estimate the control gain. The robust stability of the APISMC is proved through a Lyapunov stability analysis. Simulation results demonstrate that the modified SMC is superior to the original one for both positioning and tracking applications. Compared with the original, the proposed controller provides better performance—less chattering, faster response, and higher precision.

  10. [Review on label-free optical bio-sensing technology based on whisper-gallery-mode].

    Science.gov (United States)

    Jiang, Jun-feng; Liu, Tie-gen; Li, Hai-wei; Hui, Rong-qing; Liu, Kuni; Zhang, Yi-mo

    2010-11-01

    Optical biosensors are becoming an important tool for drug research and life science, and the label-free optical biosensor based on whisper-gallery-mode (WGM) is reviewed in the present paper. The WGM-based sensors are categorized into three types according to the microcavity structure. The biosensor using microsphere got extensive research because of high quality factor, and its response to protein, virus, and bacteria had been studied. The models based on single photon resonant state and perturbation theory were established. The biosensor using microdisk was proposed early since it can make use of mature lithography technology; however, the quality factor was increased greatly only after the thermal reflow process was introduced and single molecule measurement was then realized. The biosensor using microring has simpler mode structure and materials such as polymer, silicon nitride and silicon-on-insulator had been used for sensor fabrication. As a 3-dimension expansion, sensor using microtube can combine the optical channel and fluidic channel, which attracting more and more attention.

  11. Second Order Sliding Mode-Based Output Feedback Tracking Control for Uncertain Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Mien Van

    2013-01-01

    Full Text Available In this paper, a robust output feedback tracking control scheme for motion control of uncertain robot manipulators without joint velocity measurement based on a second-order sliding mode (SOSM observer is presented. Two second‐order sliding mode observers with finite time convergence are developed for velocity estimation and uncertainty identification, respectively. The first SOSM observer is used to estimate the state vector in finite time without filtration. However, for uncertainty identification, the values are constructed from the high switching frequencies, necessitating the application of a filter. To estimate the uncertainties without filtration, a second SOSM‐based nonlinear observer is designed. By integrating two SOSM observers, the resulting observer can theoretically obtain exact estimations of both velocity and uncertainty. An output feedback tracking control scheme is then designed based on the observed values of the state variables and the direct compensation of matched modelling uncertainty using their identified values. Finally, results of a simulation for a PUMA560 robot are shown to verify the effectiveness of the proposed strategy.

  12. Novel picture of the soft modes at the QCD critical point based on the FRG method

    CERN Document Server

    Yokota, Takeru; Morita, Kenji

    2016-01-01

    We investigate the soft mode at the QCD critical point (CP) on the basis of the functional renormalization group. We calculate the spectral functions in the meson channels in the two-flavor quark--meson model. Our result shows that the energy of the peak position of the particle--hole mode in the sigma channel becomes vanishingly small as the system approaches the QCD CP, which is a manifestation of the softening of the phonon mode. We also extract the dispersion curves of the mesonic and the phonon mode, a hydrodynamic mode which leads to a finding that the dispersion curve of the sigma-mesonic mode crosses the light-cone into the space-like momentum region, and then eventually merges into the phonon mode as the system approaches further close to the CP. This may suggest that the sigma-mesonic mode forms the soft mode together with the hydrodynamic mode at the CP.

  13. Analysis and engineering of coupled cavity waveguides based on coupled-mode theory

    Institute of Scientific and Technical Information of China (English)

    Lin Xu-Sheng; Chen Xiong-Wen; Lan Sheng

    2005-01-01

    The analytical expression for the transmission spectra of coupled cavity waveguides (CCWs) in photonic crystals (PCs) is derived based on the coupled-mode theory (CMT). Parameters in the analytical expression can be extracted by simple numerical simulations. We reveal that it is the phase shift between the two adjacent PC defects that uniquely determines the flatness of the impurity bands of CCWs. In addition, it is found that the phase shift also greatly affects the bandwidth of CCWs. Thus, the engineering of the impurity bands of CCWs can be realized through the adjustment of the phase shift. Based on the theoretical results, an interesting phenomenon in which a CCW acts as a single PC defect and its impurity band possesses a Lorentz lineshape is predicted. Very good agreement between the analytical results and the numerical simulations based on transfer matrix method has been achieved.

  14. Design of distributed Raman temperature sensing system based on single-mode optical fiber

    Institute of Scientific and Technical Information of China (English)

    Ziheng XU; Deming LIU; Hairong LIU; Qizhen SUN; Zhifeng SUN; Xu ZHANG; Wengang WANG

    2009-01-01

    The distributed optical fiber temperature sensor system based on Raman scattering has developed rapidly since it was invented in 1970s. The optical wavelengths used in most of the distributed temperature optical fiber sensor system based on the Raman scattering are around from 840 to 1330 nm, and the system operates with multimode optical fibers. However, this wavelength range is not suitable for long-distance transmission due to the high attenuation and dispersion of the transmission optical fiber. A novel distributed optical fiber Raman temperature sensor system based on standard single-mode optical fiber is proposed. The system employs the wavelength of 1550 nm as the probe light and the standard communication optical fiber as the sensing medium to increase the sensing distance. This system mainly includes three modules: the probe light transmitting module, the light magnifying and transmission module, and the signal acquisition module.

  15. Fast revelation of the motif mode for a yeast protein interaction network through intelligent agent-based distributed computing.

    Science.gov (United States)

    Lee, Wei-Po; Tzou, Wen-Shyong

    2010-09-01

    In the yeast protein-protein interaction network, motif mode, a collection of motifs of special combinations of protein nodes annotated by the molecular function terms of the Gene Ontology, has revealed differences in the conservation constraints within the same topology. In this study, by employing an intelligent agent-based distributed computing method, we are able to discover motif modes in a fast and adaptive manner. Moreover, by focusing on the highly evolutionarily conserved motif modes belonging to the same biological function, we find a large downshift in the distance between nodes belonging to the same motif mode compared with the whole, suggesting that nodes with the same motif mode tend to congregate in a network. Several motif modes with a high conservation of the motif constituents were revealed, but from a new perspective, including that with a three-node motif mode engaged in the protein fate and that with three four-node motif modes involved in the genome maintenance, cellular organization, and transcription. The network motif modes discovered from this method can be linked to the wealth of biological data which require further elucidation with regard to biological functions.

  16. Time-scaling based sliding mode control for Neuromuscular Electrical Stimulation under uncertain relative degrees.

    Science.gov (United States)

    Oliveira, Tiago Roux; Costa, Luiz Rennó; Catunda, João Marcos Yamasaki; Pino, Alexandre Visintainer; Barbosa, William; Souza, Márcio Nogueira de

    2017-03-28

    This paper addresses the application of the sliding mode approach to control the arm movements by artificial recruitment of muscles using Neuromuscular Electrical Stimulation (NMES). Such a technique allows the activation of motor nerves using surface electrodes. The goal of the proposed control system is to move the upper limbs of subjects through electrical stimulation to achieve a desired elbow angular displacement. Since the human neuro-motor system has individual characteristics, being time-varying, nonlinear and subject to uncertainties, the use of advanced robust control schemes may represent a better solution than classical Proportional-Integral (PI) controllers and model-based approaches, being simpler than more sophisticated strategies using fuzzy logic or neural networks usually applied in this control problem. The objective is the introduction of a new time-scaling base sliding mode control (SMC) strategy for NMES and its experimental evaluation. The main qualitative advantages of the proposed controller via time-scaling procedure are its independence of the knowledge of the plant relative degree and the design/tuning simplicity. The developed sliding mode strategy allows for chattering alleviation due to the impact of the integrator in smoothing the control signal. In addition, no differentiator is applied to construct the sliding surface. The stability analysis of the closed-loop system is also carried out by using singular perturbation methods. Experimental results are conducted with healthy volunteers as well as stroke patients. Quantitative results show a reduction of 45% in terms of root mean square (RMS) error (from 5.9° to [Formula: see text] ) in comparison with PI control scheme, which is similar to that obtained in the literature.

  17. A sliding mode-based starling-like controller for implantable rotary blood pumps.

    Science.gov (United States)

    Bakouri, Mohsen A; Salamonsen, Robert F; Savkin, Andrey V; AlOmari, Abdul-Hakeem H; Lim, Einly; Lovell, Nigel H

    2014-07-01

    Clinically adequate implementation of physiological control of a rotary left ventricular assist device requires a sophisticated technique such as the recently proposed method based on the Frank-Starling mechanism. In this mechanism, the stroke volume of the heart increases in response to an increase in the volume of blood filling the left ventricle at the end of diastole. To emulate this process, changes in pump speed need to automatically regulate pump flow to ensure that the combined output of the left ventricle and pump match the output of the right ventricle across changing cardiovascular states. In this approach, we exploit the linear relationship between estimated mean pump flow (Q ̅ est) and pump flow pulsatility (PIQp) in a tracking control algorithm based on sliding mode control. The immediate response of the controller was assessed using a lumped parameter model of the cardiovascular system (CVS) and pump from which could be extracted both Q ̅ est and PIQp. Two different perturbations from the resting state in the presence of left ventricular failure were tested. The first was blood loss requiring a reduction in pump flow to match the reduced output from the right ventricle and to avoid the complication of ventricular suction. The second was exercise, requiring an increase in pump flow. The sliding mode controller induced the required changes in Qp within approximately five heart beats in the blood loss simulation and eight heart beats in the exercise simulation without clinically significant transients or steady-state errors.

  18. A Source-Based Multicast Scheme in IEEE 802.16 Mesh Mode

    Directory of Open Access Journals (Sweden)

    Ali Azarpeyvand

    2012-12-01

    Full Text Available WiMAX based on IEEE 802.16 is known as one of effective technologies for transmission of multimedia to groups of receivers. There are two operational modes in WiMAX: point to multi point (PMP for single hop transmission and a mesh node for multi-hop transmission. The current standard only defines unicast transmission under mesh mode thus the performance is deteriorated for multimedia applications with multicast nature. In this paper, we first propose a mechanism for source-based tree topology construction aiming at facilitating multicast transmission in WiMAX mesh network. In the proposed approach, the multicast tree is constructed considering available link’s bandwidth and multicast group members. After constructing the multicast tree we propose a novel scheduling algorithm to improve the transmission throughout. In the proposed scheduling algorithm a parent node uses broadcasting when the number of its children belonging to a multicast group excesses a threshold. Extensive simulation results show that the proposed multicast mechanism improves multicast transmission efficiency and reduces scheduling time slots noticeably in comparison to the approach mandated by the IEEE 802.16 standard.

  19. Dip-separated structural filtering using seislet transform and adaptive empirical mode decomposition based dip filter

    Science.gov (United States)

    Chen, Yangkang

    2016-07-01

    The seislet transform has been demonstrated to have a better compression performance for seismic data compared with other well-known sparsity promoting transforms, thus it can be used to remove random noise by simply applying a thresholding operator in the seislet domain. Since the seislet transform compresses the seismic data along the local structures, the seislet thresholding can be viewed as a simple structural filtering approach. Because of the dependence on a precise local slope estimation, the seislet transform usually suffers from low compression ratio and high reconstruction error for seismic profiles that have dip conflicts. In order to remove the limitation of seislet thresholding in dealing with conflicting-dip data, I propose a dip-separated filtering strategy. In this method, I first use an adaptive empirical mode decomposition based dip filter to separate the seismic data into several dip bands (5 or 6). Next, I apply seislet thresholding to each separated dip component to remove random noise. Then I combine all the denoised components to form the final denoised data. Compared with other dip filters, the empirical mode decomposition based dip filter is data-adaptive. One only needs to specify the number of dip components to be separated. Both complicated synthetic and field data examples show superior performance of my proposed approach than the traditional alternatives. The dip-separated structural filtering is not limited to seislet thresholding, and can also be extended to all those methods that require slope information.

  20. Characteristics and help-seeking behaviors of Internet gamblers based on most problematic mode of gambling.

    Science.gov (United States)

    Hing, Nerilee; Russell, Alex Myles Thomas; Gainsbury, Sally Melissa; Blaszczynski, Alex

    2015-01-07

    Previous studies of problem Internet gamblers have failed to distinguish whether their problem gambling relates to Internet or land-based gambling modes. Therefore, characteristics and help-seeking behaviors of people whose gambling problems relate specifically to Internet gambling are unknown, but could inform the optimal alignment of treatment and support services with the needs and preferences of problem gamblers. This study aimed to compare (1) characteristics of problem Internet gamblers and problem land-based gamblers and (2) uptake of different types and modes of help between problem Internet gamblers and problem land-based gamblers. Hypothesis 1 was that problem Internet gamblers are less likely to seek help. Hypothesis 2 was that problem Internet gamblers are more likely to use online modes of help. A sample of 620 respondents meeting criteria for problem gambling was drawn from an online survey of 4594 Australian gamblers. Respondents were recruited through advertisements on gambling and gambling help websites, Facebook, and Google. Measures consisted of gambling participation; proportion of gambling on the Internet; most problematic mode of gambling; help seeking from 11 different sources of formal help, informal help, and self-help for gambling problems; psychological distress (Kessler 6); problem gambling severity (Problem Gambling Severity Index, PGSI); and demographics. Problem Internet gamblers were significantly more likely than problem land-based gamblers to be male (χ(2) 1=28.3, P<.001, φ=0.21), younger (t616.33=4.62, P<.001, d=0.37), have lower psychological distress (χ(2) 1=5.4, P=.02, φ=0.09), and experience problems with sports and race wagering (χ(2) 4=228.5, P<.001, φ=0.61). Uptake of help was significantly lower among problem Internet compared to problem land-based gamblers (χ(2) 1=6.9, P<.001, φ=0.11), including from face-to-face services, gambling helplines, online groups, self-exclusion from land-based venues, family or friends

  1. Robust motion control of oscillatory-base manipulators h∞-control and sliding-mode-control-based approaches

    CERN Document Server

    Toda, Masayoshi

    2016-01-01

    This book provides readers with alternative robust approaches to control design for an important class of systems characteristically associated with ocean-going vessels and structures. These systems, which include crane vessels, on-board cranes, radar gimbals, and a conductivity temperature and depth winch, are modelled as manipulators with oscillating bases. One design approach is based on the H-infinity control framework exploiting an effective combination of PD control, an extended matrix polytope and a robust stability analysis method with a state-dependent coefficient form. The other is based on sliding-mode control using some novel nonlinear sliding surfaces. The model demonstrates how successful motion control can be achieved by suppressing base oscillations and in the presence of uncertainties. This is important not only for ocean engineering systems in which the problems addressed here originate but more generally as a benchmark platform for robust motion control with disturbance rejection. Researche...

  2. A quality assurance technique for the static multileaf collimator mode based on intrinsic base lines

    Directory of Open Access Journals (Sweden)

    Kareem Ahmed El-Maraghy

    2014-04-01

    Full Text Available The inspection of the static leaf positions of Multileaf Collimator (MLC devices is essential for safe radiotherapy deliveries in both static and dynamic modes. The purpose of this study was to develop a robust, accurate and generic algorithm to measure the individual static MLC leaf positions. This was performed by extracting leaf tip locations from the radiographic film image and measuring their relative distance from a reference line on the film. The reference line was created with a selected set of MLC leaf sides. The film scaling was created and verified using the physical leaf width. The average measured distance corresponds to a leaf width of 10 mm was 9.95 ± 0.09 mm. The estimated reproducibility of the leaf tips location was ±0.26 mm. The code accuracy was checked by intentionally positioning set of leaves with small errors (1 mm, and the detected deviations from the expected positions ranged from −0.25 mm and +0.32 mm. The algorithm includes two self testing functions in order to detect failures of leaf positioning due to poor film quality and to avoid the potential systematic errors attributable to the improper collimator setting. The code is promising to be more efficient with Gafchromic and Electronic Portal Imaging Device (EPID.

  3. Mode Adaptive Droop Control with Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

    DEFF Research Database (Denmark)

    Kim, Jaehong; Guerrero, Josep M.; Rodriguez, Pedro;

    2011-01-01

    in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation...... control combined with a derivative controller is used in islanded mode. In grid-connected mode, to strictly control the power factor in the point of common coupling (PCC), a droop method combined with an integral controller is adopted. Small-signal analysis of the proposed control is shown both...

  4. Multichannel mode conversion and multiplexing based on a single spatial light modulator for optical communication

    Science.gov (United States)

    Nie, Song; Yu, Song; Cai, Shanyong; Lan, Mingying; Gu, Wanyi

    2016-07-01

    A method is proposed to achieve multichannel mode conversion and multiplexing by dividing a single spatial light modulator into several blocks with the mode conversion pattern and blazed grating loaded on each block. The conversion patterns realize the precise excitation of higher order modes using combined amplitude and phase modulation. The blazed gratings bring together incident beams, so these beams can be coupled into few-mode fiber (FMF). In the experiment, four higher order modes are precisely excited and converge with a tilt angle. Through the simulation method, these beams can be coupled into FMF with small tilt angles (0.0344 deg for LP11 mode).

  5. Sliding mode control for an aerodynamic missile based on backstepping design

    Institute of Scientific and Technical Information of China (English)

    Wenjin GU; Hongchao ZHAO; Changpeng PAN

    2005-01-01

    In order to solve the mismatched uncertainties of a class of nonlinear systems,a control method of sliding mode control (SMC) based on the backstepping design is proposed.It introduces SMC in to the last step of backstepping design to modify the backstepping algorithm.This combination not only enables the generalization of the backstepping design to be applied to more general nonlinear systems,but also makes the SMC method become effective in solving the mismatched uncertainties.The SMC based on the backstepping design is applied to the flight control system design of an aerodynamic missile.The control system is researched through simulation.The simulation results show the effectiveness of the proposed control method.

  6. Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

    Science.gov (United States)

    Qiu, Huaxin; Duan, Haibin

    2017-07-28

    Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Mode conversion losses in silicon-on-insulator photonic wire based racetrack resonators.

    Science.gov (United States)

    Xia, Fengnian; Sekaric, Lidija; Vlasov, Yurii A

    2006-05-01

    Two complimentary types of SOI photonic wire based devices, the add/drop (A/D) filter using a racetrack resonator and the Mach-Zehnder interferometer with one arm consisting of an identical resonator in all-pass filter (APF) configuration, were fabricated and characterized in order to extract the optical properties of the resonators and predict the performance of the optical delay lines based on such resonators. We found that instead of well-known waveguide bending and propagation losses, mode conversion loss in the coupling region of such resonators dominates when the air gap between the racetrack resonator and access waveguide is smaller than 120nm. We also show that this additional loss significantly degrades the performance of the optical delay line containing cascaded resonators in APF configuration.

  8. Ionic limiting molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory.

    Science.gov (United States)

    He, Xiangming; Pu, Weihua; Han, Jingli; Chen, Jian; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

    2005-12-15

    A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.

  9. FAULT DIAGNOSIS APPROACH FOR ROLLER BEARINGS BASED ON EMPIRICAL MODE DECOMPOSITION METHOD AND HILBERT TRANSFORM

    Institute of Scientific and Technical Information of China (English)

    Yu Dejie; Cheng Junsheng; Yang Yu

    2005-01-01

    Based upon empirical mode decomposition (EMD) method and Hilbert spectrum, a method for fault diagnosis of roller bearing is proposed. The orthogonal wavelet bases are used to translate vibration signals of a roller bearing into time-scale representation, then, an envelope signal can be obtained by envelope spectrum analysis of wavelet coefficients of high scales. By applying EMD method and Hilbert transform to the envelope signal, we can get the local Hilbert marginal spectrum from which the faults in a roller bearing can be diagnosed and fault patterns can be identified. Practical vibration signals measured from roller bearings with out-race faults or inner-race faults are analyzed by the proposed method. The results show that the proposed method is superior to the traditional envelope spectrum method in extracting the fault characteristics of roller bearings.

  10. Adaptive Actor-Critic Design-Based Integral Sliding-Mode Control for Partially Unknown Nonlinear Systems With Input Disturbances.

    Science.gov (United States)

    Fan, Quan-Yong; Yang, Guang-Hong

    2016-01-01

    This paper is concerned with the problem of integral sliding-mode control for a class of nonlinear systems with input disturbances and unknown nonlinear terms through the adaptive actor-critic (AC) control method. The main objective is to design a sliding-mode control methodology based on the adaptive dynamic programming (ADP) method, so that the closed-loop system with time-varying disturbances is stable and the nearly optimal performance of the sliding-mode dynamics can be guaranteed. In the first step, a neural network (NN)-based observer and a disturbance observer are designed to approximate the unknown nonlinear terms and estimate the input disturbances, respectively. Based on the NN approximations and disturbance estimations, the discontinuous part of the sliding-mode control is constructed to eliminate the effect of the disturbances and attain the expected equivalent sliding-mode dynamics. Then, the ADP method with AC structure is presented to learn the optimal control for the sliding-mode dynamics online. Reconstructed tuning laws are developed to guarantee the stability of the sliding-mode dynamics and the convergence of the weights of critic and actor NNs. Finally, the simulation results are presented to illustrate the effectiveness of the proposed method.

  11. Multiwavelength fiber lasers based on spatial mode beating for high resolution linear and angular displacement sensing

    Science.gov (United States)

    Chen, Nan-Kuang; Chang, Yung-Hsiang; Cheng, Wood-Hi; Guo, Tuan; Guan, Bai-Ou

    2014-05-01

    We demonstrate multiwavelength fiber lasers by incorporating the micro Michelson interferometer with spatial mode beating phenomenon, which comes from the interferences among cladding modes, into ring cavity for high resolution linear and angular displacement sensing.

  12. Theory-based transport simulations of TFTR L-mode temperature profiles

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, G.

    1991-10-24

    The temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient ({eta}{sub i}) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the periphery. Within the context of this transport model and the TFTR simulations reported here, the scaling of confinement with heating power comes from the temperature dependence of the {eta}{sub i} and trapped electron modes, while the scaling with current comes mostly from resistive ballooning modes. 24 refs., 16 figs., 3 tabs.

  13. Management of Automotive Engine Based on Stable Fuzzy Technique with Parallel Sliding Mode Optimization

    Directory of Open Access Journals (Sweden)

    Mansour Bazregar

    2013-12-01

    Full Text Available Both fuzzy logic and sliding mode can compensate the steady-state error of proportional-derivative (PD method. This paper presents parallel sliding mode optimization for fuzzy PD management. The asymptotic stability of fuzzy PD management with first-order sliding mode optimization in the parallel structure is proven. For the parallel structure, the finite time convergence with a super-twisting second-order sliding-mode is guaranteed.

  14. VR-based Operating Modes and Metaphors for Collaborative Ergonomic Design of Industrial Workstations

    OpenAIRE

    Nguyen, Huyen; Pontonnier, Charles; Hilt, Simon; Duval, Thierry; Dumont, Georges

    2016-01-01

    International audience; The aim of this paper is to evaluate two new operating design modes and their collaborative metaphors enabling two actors, a design engineer and an end-user, to work jointly in a collabora-tive virtual environment for workstation design. The two operating design modes that correspond to two different design paradigms include : direct design mode (the design engineer manipulates objects while the end-user specifies their activity constraints) and supervised design mode ...

  15. Failure mode analysis of silicon-based intracortical microelectrode arrays in non-human primates

    Science.gov (United States)

    Barrese, James C.; Rao, Naveen; Paroo, Kaivon; Triebwasser, Corey; Vargas-Irwin, Carlos; Franquemont, Lachlan; Donoghue, John P.

    2013-12-01

    Objective. Brain-computer interfaces (BCIs) using chronically implanted intracortical microelectrode arrays (MEAs) have the potential to restore lost function to people with disabilities if they work reliably for years. Current sensors fail to provide reliably useful signals over extended periods of time for reasons that are not clear. This study reports a comprehensive retrospective analysis from a large set of implants of a single type of intracortical MEA in a single species, with a common set of measures in order to evaluate failure modes. Approach. Since 1996, 78 silicon MEAs were implanted in 27 monkeys (Macaca mulatta). We used two approaches to find reasons for sensor failure. First, we classified the time course leading up to complete recording failure as acute (abrupt) or chronic (progressive). Second, we evaluated the quality of electrode recordings over time based on signal features and electrode impedance. Failure modes were divided into four categories: biological, material, mechanical, and unknown. Main results. Recording duration ranged from 0 to 2104 days (5.75 years), with a mean of 387 days and a median of 182 days (n = 78). Sixty-two arrays failed completely with a mean time to failure of 332 days (median = 133 days) while nine array experiments were electively terminated for experimental reasons (mean = 486 days). Seven remained active at the close of this study (mean = 753 days). Most failures (56%) occurred within a year of implantation, with acute mechanical failures the most common class (48%), largely because of connector issues (83%). Among grossly observable biological failures (24%), a progressive meningeal reaction that separated the array from the parenchyma was most prevalent (14.5%). In the absence of acute interruptions, electrode recordings showed a slow progressive decline in spike amplitude, noise amplitude, and number of viable channels that predicts complete signal loss by about eight years. Impedance measurements showed

  16. Robust multitask learning with three-dimensional empirical mode decomposition-based features for hyperspectral classification

    Science.gov (United States)

    He, Zhi; Liu, Lin

    2016-11-01

    Empirical mode decomposition (EMD) and its variants have recently been applied for hyperspectral image (HSI) classification due to their ability to extract useful features from the original HSI. However, it remains a challenging task to effectively exploit the spectral-spatial information by the traditional vector or image-based methods. In this paper, a three-dimensional (3D) extension of EMD (3D-EMD) is proposed to naturally treat the HSI as a cube and decompose the HSI into varying oscillations (i.e. 3D intrinsic mode functions (3D-IMFs)). To achieve fast 3D-EMD implementation, 3D Delaunay triangulation (3D-DT) is utilized to determine the distances of extrema, while separable filters are adopted to generate the envelopes. Taking the extracted 3D-IMFs as features of different tasks, robust multitask learning (RMTL) is further proposed for HSI classification. In RMTL, pairs of low-rank and sparse structures are formulated by trace-norm and l1,2 -norm to capture task relatedness and specificity, respectively. Moreover, the optimization problems of RMTL can be efficiently solved by the inexact augmented Lagrangian method (IALM). Compared with several state-of-the-art feature extraction and classification methods, the experimental results conducted on three benchmark data sets demonstrate the superiority of the proposed methods.

  17. Structure-Based Understanding of Binding Affinity and Mode of Estrogen Receptor α Agonists and Antagonists

    Science.gov (United States)

    Barron, Mace G.

    2017-01-01

    The flexible hydrophobic ligand binding pocket (LBP) of estrogen receptor α (ERα) allows the binding of a wide variety of endocrine disruptors. Upon ligand binding, the LBP reshapes around the contours of the ligand and stabilizes the complex by complementary hydrophobic interactions and specific hydrogen bonds with the ligand. Here we present a framework for quantitative analysis of the steric and electronic features of the human ERα-ligand complex using three dimensional (3D) protein-ligand interaction description combined with 3D-QSAR approach. An empirical hydrophobicity density field is applied to account for hydrophobic contacts of ligand within the LBP. The obtained 3D-QSAR model revealed that hydrophobic contacts primarily determine binding affinity and govern binding mode with hydrogen bonds. Several residues of the LBP appear to be quite flexible and adopt a spectrum of conformations in various ERα-ligand complexes, in particular His524. The 3D-QSAR was combined with molecular docking based on three receptor conformations to accommodate receptor flexibility. The model indicates that the dynamic character of the LBP allows accommodation and stable binding of structurally diverse ligands, and proper representation of the protein flexibility is critical for reasonable description of binding of the ligands. Our results provide a quantitative and mechanistic understanding of binding affinity and mode of ERα agonists and antagonists that may be applicable to other nuclear receptors. PMID:28061508

  18. Portable organic gas detection sensor based on the effect of guided-mode resonance

    Science.gov (United States)

    Guo, Liang; Wang, Qi; Huang, Yuanshen; Zhang, Dawei

    2017-01-01

    A novel organic gas detection sensor based on the effect of guided-mode resonance is proposed in this paper. The sensor is designed to operate in the visible light band. It contains four main sections: a light source, a miniature gas chamber composed of a guided-mode resonant filter, a diffraction grating, and a CCD image sensor. When bunched visible light is irradiated vertically to the gas chamber, it passes through the gas chamber and diffraction grating, and is then received by the CCD sensor. The optical signal received by the CCD sensor is then reduced to the spectrum using a specific algorithm. When organic gases are injected into the gas chamber, there is a shift in the wavelength of resonant reflection, and the magnitude of this shift is proportional to the refractive index of the gas. The large variation in the refractive indexes of industrially important organic gases means that their characteristic peak wavelengths can be easily identified. As a result, this system can quickly detect organic gases. To verify the feasibility of this technique, we use finite difference time domain solutions to simulate the results. The sensitivity of this type of sensor can reach wavelength differences of 0.001 nm, which means that the sensor has high potential for application in portable, high-precision detection systems.

  19. A Lightweight RFID Grouping-Proof Protocol Based on Parallel Mode and DHCP Mechanism

    Directory of Open Access Journals (Sweden)

    Zhicai Shi

    2017-07-01

    Full Text Available A Radio Frequency Identification (RFID grouping-proof protocol is to generate an evidence of the simultaneous existence of a group of tags and it has been applied to many different fields. For current grouping-proof protocols, there still exist some flaws such as low grouping-proof efficiency, being vulnerable to trace attack and information leakage. To improve the secure performance and efficiency, we propose a lightweight RFID grouping-proof protocol based on parallel mode and DHCP (Dynamic Host Configuration Protocol mechanism. Our protocol involves multiple readers and multiple tag groups. During the grouping-proof period, one reader and one tag group are chosen by the verifier by means of DHCP mechanism. When only a part of the tags of the chosen group exist, the protocol can also give the evidence of their co-existence. Our protocol utilizes parallel communication mode between reader and tags so as to ensure its grouping-proof efficiency. It only uses Hash function to complete the mutual authentication among verifier, readers and tags. It can preserve the privacy of the RFID system and resist the attacks such as eavesdropping, replay, trace and impersonation. Therefore the protocol is secure, flexible and efficient. It only uses some lightweight operations such as Hash function and a pseudorandom number generator. Therefore it is very suitable to some low-cost RFID systems.

  20. Flow cytometer system for single-shot biosensing based on whispering gallery modes of fluorescent microspheres

    Science.gov (United States)

    Lessard, Reno; Rousseau-Cyr, Olivier; Charlebois, Maxime; Riviere, Christophe; Mermut, Ozzy; Allen, Claudine Nı.

    2013-02-01

    We report an innovative label-free biosensor based on statistical analysis of several whispering gallery modes spectral shifts in polystyrene fluorescent microspheres using a custom microflow cytometer. Whispering gallery modes analysis enables detection of nanometer-sized analytes showing promising possibilities for virus, bacteria and molecular detection. To demonstrate this, fluorophore-doped microspheres of the appropriate size parameter are mixed in an aqueous solution. Then, a syringe pump pushes the solution through a fiber optic flow cell where a laser beam illuminates the analysis area to excite the microspheres and their fluorescence is collected. This device provides a low-cost and user friendly solution that could enhance spectrum acquisition rates up to 5 spectra per second thanks to the considerable amount of microspheres flowing through the excitation area per unit time. Finally, the fluorescence spectra are statistically investigated using an instantaneous measurement of apparent refractive index algorithm to determine a reliable value for the refractive index of the environment since the exact radius of the microsphere scanned is unknown. This refractive index becomes an effective value for the local perturbation caused by inhomogeneities on the microsphere surface and hence, determines whether or not inhomogeneities, such as bacteria, are adsorbed by comparing to a control sample. Combining a flow cell with our detection algorithm, we reduce the period of a 50 microspheres experiment from 161 minutes to 14 minutes when the flow rate is 2000 µl/h and the microsphere concentration is 5 µsphere/µl.

  1. Artificial Neuron Based on Integrated Semiconductor Quantum Dot Mode-Locked Lasers.

    Science.gov (United States)

    Mesaritakis, Charis; Kapsalis, Alexandros; Bogris, Adonis; Syvridis, Dimitris

    2016-12-19

    Neuro-inspired implementations have attracted strong interest as a power efficient and robust alternative to the digital model of computation with a broad range of applications. Especially, neuro-mimetic systems able to produce and process spike-encoding schemes can offer merits like high noise-resiliency and increased computational efficiency. Towards this direction, integrated photonics can be an auspicious platform due to its multi-GHz bandwidth, its high wall-plug efficiency and the strong similarity of its dynamics under excitation with biological spiking neurons. Here, we propose an integrated all-optical neuron based on an InAs/InGaAs semiconductor quantum-dot passively mode-locked laser. The multi-band emission capabilities of these lasers allows, through waveband switching, the emulation of the excitation and inhibition modes of operation. Frequency-response effects, similar to biological neural circuits, are observed just as in a typical two-section excitable laser. The demonstrated optical building block can pave the way for high-speed photonic integrated systems able to address tasks ranging from pattern recognition to cognitive spectrum management and multi-sensory data processing.

  2. Crude oil price analysis and forecasting based on variational mode decomposition and independent component analysis

    Science.gov (United States)

    E, Jianwei; Bao, Yanling; Ye, Jimin

    2017-10-01

    As one of the most vital energy resources in the world, crude oil plays a significant role in international economic market. The fluctuation of crude oil price has attracted academic and commercial attention. There exist many methods in forecasting the trend of crude oil price. However, traditional models failed in predicting accurately. Based on this, a hybrid method will be proposed in this paper, which combines variational mode decomposition (VMD), independent component analysis (ICA) and autoregressive integrated moving average (ARIMA), called VMD-ICA-ARIMA. The purpose of this study is to analyze the influence factors of crude oil price and predict the future crude oil price. Major steps can be concluded as follows: Firstly, applying the VMD model on the original signal (crude oil price), the modes function can be decomposed adaptively. Secondly, independent components are separated by the ICA, and how the independent components affect the crude oil price is analyzed. Finally, forecasting the price of crude oil price by the ARIMA model, the forecasting trend demonstrates that crude oil price declines periodically. Comparing with benchmark ARIMA and EEMD-ICA-ARIMA, VMD-ICA-ARIMA can forecast the crude oil price more accurately.

  3. Artificial Neuron Based on Integrated Semiconductor Quantum Dot Mode-Locked Lasers

    Science.gov (United States)

    Mesaritakis, Charis; Kapsalis, Alexandros; Bogris, Adonis; Syvridis, Dimitris

    2016-12-01

    Neuro-inspired implementations have attracted strong interest as a power efficient and robust alternative to the digital model of computation with a broad range of applications. Especially, neuro-mimetic systems able to produce and process spike-encoding schemes can offer merits like high noise-resiliency and increased computational efficiency. Towards this direction, integrated photonics can be an auspicious platform due to its multi-GHz bandwidth, its high wall-plug efficiency and the strong similarity of its dynamics under excitation with biological spiking neurons. Here, we propose an integrated all-optical neuron based on an InAs/InGaAs semiconductor quantum-dot passively mode-locked laser. The multi-band emission capabilities of these lasers allows, through waveband switching, the emulation of the excitation and inhibition modes of operation. Frequency-response effects, similar to biological neural circuits, are observed just as in a typical two-section excitable laser. The demonstrated optical building block can pave the way for high-speed photonic integrated systems able to address tasks ranging from pattern recognition to cognitive spectrum management and multi-sensory data processing.

  4. SAR image change detection algorithm based on stationary wavelet and bi-dimensional intrinsic mode function

    Science.gov (United States)

    Huang, S. Q.; Wang, Z. L.; Xie, T. G.; Li, Z. C.

    2017-09-01

    Speckle noise in synthetic aperture radar (SAR) image is produced by the coherent imaging mechanism, which brings a great impact on the change information acquisition of multi-temporal SAR images. Two-dimensional stationary wavelet transform (SWT) and bi-dimensional empirical mode decomposition (BEMD) are the non-stationary signal processing theory of multi-scale transform. According to their implementation process and SAR image characteristic, this paper proposed a new multi-temporal SAR image change detection method based on the combination of the stationary wavelet transform and the bi-dimensional intrinsic mode function (BIMF) features, called SWT-BIMF algorithm. The contribution of the new algorithm includes two aspects. One is the design of the two selections of decomposition features, that is, the speckle noise filtering; another is the selected features to perform the enhance processing, so more effective change information will obtain. The feasibility of the SWT-BIMF algorithm is verified by the measured SAR image data, and good experimental results are obtained.

  5. Complete enumeration of elementary flux modes through scalable demand-based subnetwork definition.

    Science.gov (United States)

    Hunt, Kristopher A; Folsom, James P; Taffs, Reed L; Carlson, Ross P

    2014-06-01

    Elementary flux mode analysis (EFMA) decomposes complex metabolic network models into tractable biochemical pathways, which have been used for rational design and analysis of metabolic and regulatory networks. However, application of EFMA has often been limited to targeted or simplified metabolic network representations due to computational demands of the method. Division of biological networks into subnetworks enables the complete enumeration of elementary flux modes (EFMs) for metabolic models of a broad range of complexities, including genome-scale. Here, subnetworks are defined using serial dichotomous suppression and enforcement of flux through model reactions. Rules for selecting appropriate reactions to generate subnetworks are proposed and tested; three test cases, including both prokaryotic and eukaryotic network models, verify the efficacy of these rules and demonstrate completeness and reproducibility of EFM enumeration. Division of models into subnetworks is demand-based and automated; computationally intractable subnetworks are further divided until the entire solution space is enumerated. To demonstrate the strategy's scalability, the splitting algorithm was implemented using an EFMA software package (EFMTool) and Windows PowerShell on a 50 node Microsoft high performance computing cluster. Enumeration of the EFMs in a genome-scale metabolic model of a diatom, Phaeodactylum tricornutum, identified ∼2 billion EFMs. The output represents an order of magnitude increase in EFMs computed compared with other published algorithms and demonstrates a scalable framework for EFMA of most systems. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Mode decomposition based on crystallographic symmetry in the band-unfolding method

    Science.gov (United States)

    Ikeda, Yuji; Carreras, Abel; Seko, Atsuto; Togo, Atsushi; Tanaka, Isao

    2017-01-01

    The band-unfolding method is widely used to calculate the effective band structures of a disordered system from its supercell model. The unfolded band structures show the crystallographic symmetry of the underlying structure, where the difference of chemical components and the local atomic relaxation are ignored. However, it has still been difficult to decompose the unfolded band structures into the modes based on the crystallographic symmetry of the underlying structure, and therefore detailed analyses of the unfolded band structures have been restricted. In this study, a procedure to decompose the unfolded band structures according to the small representations (SRs) of the little groups is developed. The decomposition is performed using the projection operators for SRs derived from the group representation theory. The current method is employed to investigate the phonon band structure of disordered face-centered-cubic Cu0.75Au0.25 , which has large variations of atomic masses and force constants among the atomic sites due to the chemical disorder. In the unfolded phonon band structure, several peculiar behaviors such as discontinuous and split branches are found in the decomposed modes corresponding to specific SRs. They are found to occur because different combinations of the chemical elements contribute to different regions of frequency.

  7. Mode Research on Space Weapons Systems Innovation Based Quality Function Deployment

    Directory of Open Access Journals (Sweden)

    Wang Xiuhong

    2011-06-01

    Full Text Available in the aviation industry, experts are enthusiastic over the research of sophisticated weapons. Little specialist pays attention to the innovation modes and methods. Up to now little quantization method suitable for aviation weapon systems innovation is presented. Base on the deep analysis and study on features of aviation weapon systems innovation and different innovation mode from the mass production, we have designed process model and quality chain model of aviation weapon systems innovation. Compared with the process model of large-scale innovation, the process models are more complex including many feedbacks and adding five steps: task decomposition, analysis of knowledge gap, accumulation of key knowledge, outsourcing selection, system integration. Meanwhile manufacturing process and R&D process are preformed simultaneously, and are involved in the process of module development. Technology application and diffusion are preformed with delivering the final innovation product to user. Quality function deployment and quality house are adopted to deal with the quality transfer among nodes. Quality demands of one node are converted into the technique features of another node in the quality house. We designed the top-down technique features transfer model and bottom-up demands transfer model to solve the quality transfer problems among nodes. At last an example is given to illustrate that this approach can accelerate to blaze the aviation weapon systems trails more than the existing methods and effectively reach quality management of aviation weapon systems innovation.

  8. Partial differential equation-based approach for empirical mode decomposition: application on image analysis.

    Science.gov (United States)

    Niang, Oumar; Thioune, Abdoulaye; El Gueirea, Mouhamed Cheikh; Deléchelle, Eric; Lemoine, Jacques

    2012-09-01

    The major problem with the empirical mode decomposition (EMD) algorithm is its lack of a theoretical framework. So, it is difficult to characterize and evaluate this approach. In this paper, we propose, in the 2-D case, the use of an alternative implementation to the algorithmic definition of the so-called "sifting process" used in the original Huang's EMD method. This approach, especially based on partial differential equations (PDEs), was presented by Niang in previous works, in 2005 and 2007, and relies on a nonlinear diffusion-based filtering process to solve the mean envelope estimation problem. In the 1-D case, the efficiency of the PDE-based method, compared to the original EMD algorithmic version, was also illustrated in a recent paper. Recently, several 2-D extensions of the EMD method have been proposed. Despite some effort, 2-D versions for EMD appear poorly performing and are very time consuming. So in this paper, an extension to the 2-D space of the PDE-based approach is extensively described. This approach has been applied in cases of both signal and image decomposition. The obtained results confirm the usefulness of the new PDE-based sifting process for the decomposition of various kinds of data. Some results have been provided in the case of image decomposition. The effectiveness of the approach encourages its use in a number of signal and image applications such as denoising, detrending, or texture analysis.

  9. The single-longitudinal-mode operation of a ridge waveguide laser based on two-dimensional photonic crystals

    Institute of Scientific and Technical Information of China (English)

    Wang Hua-Yong; Xu Xing-Sheng

    2013-01-01

    An electrically driven,single-longitudinal-mode GaAs based photonic crystal (PC) ridge waveguide (RWG) laser emitting at around 850 nm is demonstrated.The single-longitudinal-mode lasing characteristic is achieved by introducing the PC to the RWG laser.The triangle PC is etched on both sides of the ridge by photolithography and inductive coupled plasma (ICP) etching.The lasing spectra of the RWG lasers with and without the PC are studied,and the result shows that the PC purifies the longitudinal mode.The power per facet versus current and current-voltage characteristics have also been studied and compared.

  10. Application of Piezoelectric Materials in a Novel Linear Ultrasonic Motor based on Shear-induced Vibration Mode

    Institute of Scientific and Technical Information of China (English)

    CHEN Chao; SHI Yunlai; CHEN Haipeng; ZHAO Chunsheng

    2014-01-01

    A novel linear ultrasonic motor based on d15 effect of piezoelectric materials was presented. The design idea aimed at the direct utilization of the shear-induced vibration modes of piezoelectric material. Firstly, the inherent electromechanical coupling mechanism of piezoelectric material was investigated, and shear vibration modes of a piezoelectric shear block was specially designed. A driving point’s elliptical trajectory induced by shear vibration modes was discussed. Then a dynamic model for the piezoelectric shear stator was established with finite element (FE) method to conduct the parametric optimal design. Finally, a prototype based on d15 converse piezoelectric effect is manufactured, and the modal experiment of piezoelectric stator was conducted with laser doppler vibrometer. The experimental results show that the calculated shear-induced vibration modes can be excited completely, and the new linear ultrasonic motor reaches a speed 118 mm/s at no-load, and maximal thrust 12.8 N.

  11. Unconventional Geometric Phase-Shift Gates Based on Superconducting Quantum Interference Devices Coupled to a Single-Mode Cavity

    Institute of Scientific and Technical Information of China (English)

    SONG Ke-Hui; ZHOU Zheng-Wei; GUO Guang-Can

    2006-01-01

    We present a scheme to realize geometric phase-shift gate for two superconducting quantum interference device (SQUID) qubits coupled to a single-mode microwave field. The geometric phase-shift gate operation is performed transitions during the gate operation. Thus, the docoherence due to energy spontaneous emission based on the levels of SQUIDs are suppressed. The gate is insensitive to the cavity decay throughout the operation since the cavity mode is displaced along a circle in the phase space, acquiring a phase conditional upon the two lower flux states of the SQUID qubits, and the cavity mode is still in the original vacuum state. Based on the SQUID qubits interacting with the cavity mode, our proposed approach may open promising prospects for quantum logic in SQUID-system.

  12. Design and optimization of fundamental mode filters based on long-period fiber gratings

    Science.gov (United States)

    Chen, Ming-Yang; Wei, Jin; Sheng, Yong; Ren, Nai-Fei

    2016-07-01

    A segment of long-period fiber grating (LPFG) that can selectively filter the fundamental mode in the few-mode optical fiber is proposed. By applying an appropriate chosen surrounding material and an apodized configuration of LPFG, high fundamental mode loss and low high-order core mode loss can be achieved simultaneously. In addition, we propose a method of cascading LPFGs with different periods to expand the bandwidth of the mode filter. Numerical simulation shows that the operating bandwidth of the cascade structure can be as large as 23 nm even if the refractive index of the surrounding liquid varies with the environment temperature.

  13. Breech at term--mode of delivery? A register-based study

    DEFF Research Database (Denmark)

    1995-01-01

    . Register-based cohort study of all (n = 15718) singleton term breech deliveries of non-malformed infants in Denmark 1982-1990. Process and outcome measures: mode of delivery, gestational age, birth weight, congenital malformations, intrapartum death, Apgar scores and early neonatal death. RESULTS. A total...... of 3247 (20.7%) term infants were delivered vaginally, 7106 (45.3%) by elective and 5356 (34.1%) by emergency cesarean section. Infants delivered vaginally and by emergency cesarean section had significantly higher rates of mortality (intrapartum and early neonatal death) and morbidity (low Apgar scores......) when compared to those delivered by elective cesarean section. In vaginal deliveries, parity was not correlated with outcome, but infants with a birth weight above 4000 grams had significantly higher rates of low Apgar scores. CONCLUSIONS. Register data on singleton term breech deliveries imply...

  14. Research on Space Target Recognition Algorithm Based on Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Shen Yiying

    2013-07-01

    Full Text Available The space target recognition algorithm, which is based on the time series of radar cross section (RCS, is proposed in this paper to solve the problems of space target recognition in the active radar system. In the algorithm, EMD method is applied for the first time to extract the eigen of RCS time series. The normalized instantaneous frequencies of high-frequency intrinsic mode functions obtained by EMD are used as the eigen values for the recognition, and an effective target recognition criterion is established. The effectiveness and the stability of the algorithm are verified by both simulation data and real data. In addition, the algorithm could reduce the estimation bias of RCS caused by inaccurate evaluation, and it is of great significance in promoting the target recognition ability of narrow-band radar in practice.  

  15. Fault tolerant control based on interval type-2 fuzzy sliding mode controller for coaxial trirotor aircraft.

    Science.gov (United States)

    Zeghlache, Samir; Kara, Kamel; Saigaa, Djamel

    2015-11-01

    In this paper, a robust controller for a Six Degrees of Freedom (6 DOF) coaxial trirotor helicopter control is proposed in presence of defects in the system. A control strategy based on the coupling of the interval type-2 fuzzy logic control and sliding mode control technique are used to design a controller. The main purpose of this work is to eliminate the chattering phenomenon and guaranteeing the stability and the robustness of the system. In order to achieve this goal, interval type-2 fuzzy logic control has been used to generate the discontinuous control signal. The simulation results have shown that the proposed control strategy can greatly alleviate the chattering effect, and perform good reference tracking in presence of defects in the system.

  16. Discrete Second-Order Sliding Mode Adaptive Controller Based on Characteristic Model for Servo Systems

    Directory of Open Access Journals (Sweden)

    Zhihong Wang

    2015-01-01

    Full Text Available Considering the varying inertia and load torque in high speed and high accuracy servo systems, a novel discrete second-order sliding mode adaptive controller (DSSMAC based on characteristic model is proposed, and a command observer is also designed. Firstly, the discrete characteristic model of servo systems is established. Secondly, the recursive least square algorithm is adopted to identify time-varying parameters in characteristic model, and the observer is applied to predict the command value of next sample time. Furthermore, the stability of the closed-loop system and the convergence of the observer are analyzed. The experimental results show that the proposed method not only can adapt to varying inertia and load torque, but also has good disturbance rejection ability and robustness to uncertainties.

  17. Decentralized model reference adaptive sliding mode control based on fuzzy model

    Institute of Scientific and Technical Information of China (English)

    Gu Haijun; Zhang Tianping; Shen Qikun

    2006-01-01

    A new design scheme of decentralized model reference adaptive sliding mode controller for a class of MIMO nonlinear systems with the high-order interconnections is proposed. The design is based on the universal approximation capability of the Takagi - Seguno (T-S) fuzzy systems. Motivated by the principle of certainty equivalentcontrol, a decentralized adaptive controller is designed to achieve the tracking objective without computation of the T-S fuzz ymodel. The approach does not require the upper bound of the uncertainty term to be known through some adaptive estimation. By theoretical analysis, the closed-loop fuzzy control system is proven to be globally stable in the sense that all signalsinvolved are bounded, with tracking errors converging to zero. Simulation results demonstrate the effectiveness of the approach.

  18. Adaptive sliding mode controller based on super-twist observer for tethered satellite system

    Science.gov (United States)

    Keshtkar, Sajjad; Poznyak, Alexander

    2016-09-01

    In this work, the sliding mode control based on the super-twist observer is presented. The parameters of the controller as well as the observer are admitted to be time-varying and depending on available current measurements. In view of that, the considered controller is referred to as an adaptive one. It is shown that the deviations of the generated state estimates from real state values together with a distance of the closed-loop system trajectories to a desired sliding surface reach a μ-zone around the origin in finite time. The application of the suggested controller is illustrated for the orientation of a tethered satellite system in a required position.

  19. A new predistortion based on the double-mode adaptive technique for satellite communications

    Science.gov (United States)

    Wang, Henghui; Zhang, Hao; Ye, Wu; Feng, Suili

    2005-11-01

    Satellite communication channels are equipped with the Traveling Wave Tube (TWT) amplifiers which cause severe nonlinear distortions when they work near saturation. In this paper, a new predistorter is designed based on the double-mode adaptive technique. Firstly, a neural network is used to design the amplitude predistorter, and the error-filtering scheme is applied to improve the classical structure of adaptive control, hence the convergent process turns to be rapid by using the LMS algorithm. Secondly, a real polynomial is applied to identify the phase character of TWT, and then the negative polynomial is copied to the transmitted path. Simulation results show that the compensated system is characterized by the approximately ideal amplifier within the range of saturated input value.

  20. Characterization of a Rydberg atom-based streak camera operating in synchroscan mode

    Science.gov (United States)

    Rella, C. W.; van der Meer, A. F. G.; Noordam, L. D.

    2000-06-01

    A streak camera that operates in synchroscan mode has been developed with a spectral response throughout the infrared. A gas-phase sample of Rydberg atoms is used as a photocathode. This compact device possesses 5 ps time resolution and can be used with a total infrared energy of about 1 nJ, or 10 -7 of the total macropulse energy of the FELIX free electron laser. This combination of characteristics makes it not only an attractive device for use in a variety of infrared experiments, but also a powerful tool for the study of photo-induced electron emission in atomic systems. As an example, a Rydberg-atom based electron gun which produces about 20 pulses of electrons at a 70 GHz repetition frequency has been characterized using this synchroscan streak camera.

  1. A Longitudinal Mode Electromagnetic Acoustic Transducer (EMAT Based on a Permanent Magnet Chain for Pipe Inspection

    Directory of Open Access Journals (Sweden)

    Ming Cong

    2016-05-01

    Full Text Available A new electromagnetic acoustic transducer (EMAT design, employing a special structure of the permanent magnet chain, is proposed to generate and receive longitudinal guided waves for pipe inspection based on the magnetostriction mechanism. Firstly, a quantitative analysis of the excitation forces shows the influence of the radial component can be ignored. Furthermore, as the axial component of the static magnetic field is dominant, a method of solenoid testing coils connected in series is adopted to increase the signal amplitude. Then, two EMAT configurations are developed to generate and receive the L(0,2 guided wave mode. The experimental results show the circumferential notch can be identified and located successfully. Finally, a detailed investigation of the performance of the proposed EMATs is given. Compared to the conventional EMAT configuration, the proposed configurations have the advantages of small volume, light weight, easy installation and portability, which is helpful to improve inspection efficiency.

  2. A Longitudinal Mode Electromagnetic Acoustic Transducer (EMAT) Based on a Permanent Magnet Chain for Pipe Inspection.

    Science.gov (United States)

    Cong, Ming; Wu, Xinjun; Qian, Chunqiao

    2016-05-21

    A new electromagnetic acoustic transducer (EMAT) design, employing a special structure of the permanent magnet chain, is proposed to generate and receive longitudinal guided waves for pipe inspection based on the magnetostriction mechanism. Firstly, a quantitative analysis of the excitation forces shows the influence of the radial component can be ignored. Furthermore, as the axial component of the static magnetic field is dominant, a method of solenoid testing coils connected in series is adopted to increase the signal amplitude. Then, two EMAT configurations are developed to generate and receive the L(0,2) guided wave mode. The experimental results show the circumferential notch can be identified and located successfully. Finally, a detailed investigation of the performance of the proposed EMATs is given. Compared to the conventional EMAT configuration, the proposed configurations have the advantages of small volume, light weight, easy installation and portability, which is helpful to improve inspection efficiency.

  3. Tempo and mode of speciation in Holacanthus angelfishes based on RADseq markers.

    Science.gov (United States)

    Tariel, Juliette; Longo, Gary C; Bernardi, Giacomo

    2016-05-01

    In this study we estimated the timing of speciation events in a group of angelfishes using 1186 RADseq markers corresponding to 94,880 base pairs. The genus Holacanthus comprises seven species, including two clades of Panama trans-Isthmian geminates, which diverged approximately 3-3.5Mya. These clades diversified within the Tropical Eastern Pacific (TEP, three species) and Tropical Western Atlantic (TWA, two species) which our data suggest to have occurred within the past 1.5My in both ocean basins, but may have proceeded via different mechanisms. In the TEP, speciation is likely to have followed a peripatric pathway, while in the TWA, sister species are currently partially sympatric, thus raising the possibility of sympatric speciation. This study highlights the use of RADseq markers for estimating both divergence times and modes of speciation at a 1-3My timescale.

  4. Differential microstrip lines with reduced crosstalk and common mode effect based on spoof surface plasmon polaritons.

    Science.gov (United States)

    Wu, Jin Jei; Hou, Da Jun; Liu, Kexin; Shen, Linfang; Tsai, Chi An; Wu, Chien Jang; Tsai, Dichi; Yang, Tzong-Jer

    2014-11-03

    We apply the concept of spoof surface plasmon polaritons (SPPs) to the design of differential microstrip lines by introducing periodic subwavelength corrugations on their edges. The dispersion relation and field distribution of those lines are analyzed numerically. And then through designing practical coupling circuits, we found that compared with conventional differential microstrip lines, the electromagnetic field can be strongly confined inside the grooves of the corrugated microstrip lines, so the crosstalk between the differential pair and the adjacent microstrip lines is greatly reduced, and the conversion from the differential signal to the common mode signal can also be effectively suppressed. The propagation length of those lines is also very long in a wide band. Moreover, the experimental results in time domain demonstrate those lines perform very well in high-speed circuit. Therefore, those novel kinds of spoof SPPs based differential microstrip lines can be widely utilized in high-density microwave circuits and guarantee signal integrity in high-speed systems.

  5. Passively harmonic mode-locked fiber laser based on ReS2 saturable absorber

    Science.gov (United States)

    Lu, Feifei

    2017-06-01

    We demonstrate the generation of harmonic mode-locking (HML) in an erbium-doped fiber laser with a microfiber-based rhenium disulfide (ReS2) saturable absorber (SA). Taking advantages of both saturable absorption and large third-order nonlinear effect of ReS2, HML pulse with 318.5 MHz repetition rate can be obtained, corresponding to 168th harmonic of fundamental repetition frequency of 1.896 MHz. When the pump power is increased gradually, the pulse interval remains constant, while the output power increases linearly. At the pump power of 450 mW, the output power is ˜12 mW. The proposed high-repetition-rate pulse lasers would attract considerable attention due to its potential applications in soliton communications and frequency combs.

  6. Analysis of a Triple-cavity Photonic Molecule Based on Coupled Mode Theory

    CERN Document Server

    Yang, Chao; Jiang, Xiaoshun; Xiao, Min

    2016-01-01

    In this paper, we analyze a chain-linked triple-cavity photonic molecule (TCPM) with controllable coupling strengths between the cavities on their spectral properties and field (energy) distributions by solving eigenvalues and eigenvectors of the Hamiltonian matrix based on coupled mode theory. Phase transition is extended from double-cavity photonic molecules (DCPMs) to TCPMs, and evolutions of the supermode frequencies and linewidths are analyzed, which have synchronous relations with the degree of coherence between adjacent optical microcavities and energy distributions in the three cavities, respectively. We develop a superposition picture for the three supermodes of the TCPM, as interferences between supermodes of sub-DCPMs. In particular, we demonstrate the abnormal properties of the central supermode in TCPMs, such as dark state in middle cavity and phase shift when energy flowing between side cavities, which are promising in information processing and remote control of energy. General properties of TC...

  7. Comparison of Fourier and model-based estimators in single mode multiaxial interferometry

    CERN Document Server

    Tatulli, E

    2006-01-01

    There are several solutions to code the signal arising from optical long baseline multi-aperture interferometers. In this paper,we focus on the {\\bf non homothetic spatial coding scheme} (multiaxial) with the fringe pattern coded along one dimension on one detector(all-in-one). After describing the physical principles governing single mode interferometers using that sort of recombination scheme, we analyze two different existing methods that measure the source visibility. The first technique, so-called Fourier estimator, consists in integrating the high frequency peak of the power spectral density of the interferogram. The second method, so-called model-based estimator, has been specifically developed for the AMBER instrument of the VLTI and deals with directly modelling the interferogram recorded on the detector. Performances of both estimators are computed in terms of Signal to Noise Ratio (SNR) of the visibility, assuming that the interferograms are perturbed by photon and detector noises. Theoretical expr...

  8. Wind turbine efficiency optimization. Comparative study of controllers based on second order sliding modes

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista, C.; Puleston, P.; Valenciaga, F. [CONICET and LEICI, Faculty of Engineering, National University of La Plata, C.C.91 (1900) La Plata (Argentina)

    2010-06-15

    This paper studies the applicability of second order sliding mode control strategies to a wind energy conversion system aiming to optimise its power conversion efficiency. Four different controllers are designed and analysed, based on the ''sub-optimal'', ''twisting'', ''super-twisting'' and ''with a prescribed law of variation'' algorithms, which present finite-time convergence, robustness, chattering and mechanical stress reduction, and are of quite simple online operation and implementation. Representative simulation results are shown, using a complete model of the system under realistic operating conditions, where the performance of the controlled system can be appreciated for each of the controllers and some comparisons can be made. (author)

  9. Determining the Most Vital Arcs Within a Multi-Mode Communication Network Using Set-Based Measures

    Science.gov (United States)

    2015-03-26

    Determining the Most Vital Arcs Within a Multi-Mode Communication Network Using Set-Based Measures THESIS MARCH 2015 Christopher A. Hergenreter, Capt...material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. AFIT-ENS-MS-15-M-131 DETERMINING THE MOST ...STATEMENT A APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENS-MS-15-M-131 DETERMINING THE MOST VITAL ARCS WITHIN A MULTI-MODE COMMUNICATION

  10. Optical microcavities based on surface modes in two-dimensional photonic crystals and silicon-on-insulator photonic crystals

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Qiu, M.

    2007-01-01

    Surface-mode optical microcavities based on two-dimensional photonic crystals and silicon-on-insulator photonic crystals are studied. We demonstrate that a high-quality-factor microcavity can be easily realized in these structures. With an increasing of the cavity length, the quality factor...... is gradually enhanced and the resonant frequency converges to that of the corresponding surface mode in the photonic crystals. These structures have potential applications such as sensing....

  11. A Novel Fuzzy Logic Based Adaptive Super-Twisting Sliding Mode Control Algorithm for Dynamic Uncertain Systems

    OpenAIRE

    Abdul Kareem; Mohammad Fazle Azeem

    2012-01-01

    This paper presents a novel fuzzy logic based Adaptive Super-twisting Sliding Mode Controller for the control of dynamic uncertain systems. The proposed controller combines the advantages of Second order Sliding Mode Control, Fuzzy Logic Control and Adaptive Control. The reaching conditions, stability and robustness of the system with the proposed controller are guaranteed. In addition, the proposed controller is well suited for simple design and implementation. The effectiveness ...

  12. Mode extraction on wind turbine blades via phase-based video motion estimation

    Science.gov (United States)

    Sarrafi, Aral; Poozesh, Peyman; Niezrecki, Christopher; Mao, Zhu

    2017-04-01

    In recent years, image processing techniques are being applied more often for structural dynamics identification, characterization, and structural health monitoring. Although as a non-contact and full-field measurement method, image processing still has a long way to go to outperform other conventional sensing instruments (i.e. accelerometers, strain gauges, laser vibrometers, etc.,). However, the technologies associated with image processing are developing rapidly and gaining more attention in a variety of engineering applications including structural dynamics identification and modal analysis. Among numerous motion estimation and image-processing methods, phase-based video motion estimation is considered as one of the most efficient methods regarding computation consumption and noise robustness. In this paper, phase-based video motion estimation is adopted for structural dynamics characterization on a 2.3-meter long Skystream wind turbine blade, and the modal parameters (natural frequencies, operating deflection shapes) are extracted. Phase-based video processing adopted in this paper provides reliable full-field 2-D motion information, which is beneficial for manufacturing certification and model updating at the design stage. The phase-based video motion estimation approach is demonstrated through processing data on a full-scale commercial structure (i.e. a wind turbine blade) with complex geometry and properties, and the results obtained have a good correlation with the modal parameters extracted from accelerometer measurements, especially for the first four bending modes, which have significant importance in blade characterization.

  13. Current-mode implementation of processing modules in ART-based neural networks

    Science.gov (United States)

    Lopez-Alcantud, Jose-Alejandro; Hauer, Hans; Diaz-Madrid, Jose-Angel; Ruiz-Merino, Ramon

    2003-04-01

    This paper describes implementation of neural network processing layers using basic current-mode operating modules. The research work has been focused on the implementation of neural networks based on the Adaptive Resonance Theory, developed by S. Grossberg and G.A. Carpenter. The ART-based neural network whose operating modules have been choosen for development is the one called MART, proposed by F. Delgado, because of its complex architecture, auto--adaptive self-learning process, able to discard unmeaningful cathegories. Our presentation starts introducing the behaviour of MART with an analysis of its structure. The development described by this research work is focused on the monochannel block included in the main signal processing part of the MART neural network. The description of the computing algorithm of the layers inside a monochannel block are also provided in order to show what operational current-mode modules are needed (multiplier, divider, square-rooter, adder, substractor, absolute value, maximum and minimum evaluator...). Descriptions at schematic and layout levels of all the processing layers are given. All of them have been designed using AMS 0.35 micron technology with a supply voltage of 3.3 volts. The modules are designed to deal with input currents in the range of 20 to 50 microamps, showing a lineal behaviour and an output error of less than 10%, which is good enough for neural signal processing systems. The maximum frecuency of operation is around 200 kHz. Simulation results are included to show that the operation performed by the hardware designed matches the behaviour described by the MART neural network. For testing purposes we show the design of a monochannel block hardware implementation restricted to five inputs and three cathegories.

  14. Mode Evaluation and Structure Design of Connection between Pole and Base of Roadside Breakaway Sign in China

    Directory of Open Access Journals (Sweden)

    Liang Xu

    2016-01-01

    Full Text Available In order to present reliable mode and structure of connection between pole and base for breakaway sign, mode evaluation and structure design were conducted in this paper. AHP was adopted to evaluate connection modes between sign pole and base. Analytic hierarchy with double criterion layer and corresponding judgment matrix were established. Through qualitative analysis, powers of indexes were given and evaluation results were presented based on standardization process of each evaluation index. It shows that brittle connection mode comes in the first place, the plastic connection mode comes second, and rigid connection mode comes last. Two brittle connection structures were designed through the finite element simulation analysis. By ANSYS software, stress data were given for recessed and hole-type connection design structure. It can be found that maximum tensile stress data of two connection structures are all more than ultimate tensile strength of steel. Thus it can be concluded that two connection structures designed in this paper can be breakaway in collision and protect the safety of vehicle occupants.

  15. The shareholding similarity of the shareholders of the worldwide listed energy companies based on a two-mode primitive network and a one-mode derivative holding-based network

    Science.gov (United States)

    Li, Huajiao; Fang, Wei; An, Haizhong; Yan, LiLi

    2014-12-01

    Two-mode and multi-mode networks represent new directions of simulating a complex network that can simulate the relationships among the entities more precisely. In this paper, we constructed two different levels of networks: one is the two-mode primitive networks of the energy listed companies and their shareholders on the basis of the two-mode method of complex theory, and the other is the derivative one-mode holding-based network based on the equivalence network theory. We calculated two different topological characteristics of the two networks, that is, the out-degree of the actor nodes of the two-mode network (9003 nodes) and the weights of the edges of the one-mode network (619,766 edges), and we analyzed the distribution features of both of the two topological characteristics. In this paper, we define both the weighted and un-weighted Shareholding Similarity Coefficient, and using the data of the worldwide listed energy companies and their shareholders as empirical study subjects, we calculated and compared both the weighted and un-weighted shareholding similarity coefficient of the worldwide listed energy companies. The result of the analysis indicates that (1) both the out-degree of the actor nodes of the two-mode network and the weights of the edges of the one-mode network follow a power-law distribution; (2) there are significant differences between the weighted and un-weighted shareholding similarity coefficient of the worldwide listed energy companies, and the weighted shareholding similarity coefficient is of greater regularity than the un-weighted one; (3) there are a vast majority of shareholders who hold stock in only one or a few of the listed energy companies; and (4) the shareholders hold stock in the same listed energy companies when the value of the un-weighted shareholding similarity coefficient is between 0.4 and 0.8. The study will be a helpful tool to analyze the relationships of the nodes of the one-mode network, which is constructed based

  16. Model predictive control of an air suspension system with damping multi-mode switching damper based on hybrid model

    Science.gov (United States)

    Sun, Xiaoqiang; Yuan, Chaochun; Cai, Yingfeng; Wang, Shaohua; Chen, Long

    2017-09-01

    This paper presents the hybrid modeling and the model predictive control of an air suspension system with damping multi-mode switching damper. Unlike traditional damper with continuously adjustable damping, in this study, a new damper with four discrete damping modes is applied to vehicle semi-active air suspension. The new damper can achieve different damping modes by just controlling the on-off statuses of two solenoid valves, which makes its damping adjustment more efficient and more reliable. However, since the damping mode switching induces different modes of operation, the air suspension system with the new damper poses challenging hybrid control problem. To model both the continuous/discrete dynamics and the switching between different damping modes, the framework of mixed logical dynamical (MLD) systems is used to establish the system hybrid model. Based on the resulting hybrid dynamical model, the system control problem is recast as a model predictive control (MPC) problem, which allows us to optimize the switching sequences of the damping modes by taking into account the suspension performance requirements. Numerical simulations results demonstrate the efficacy of the proposed control method finally.

  17. Modeling mode choice behavior incorporating household and individual sociodemographics and travel attributes based on rough sets theory.

    Science.gov (United States)

    Cheng, Long; Chen, Xuewu; Wei, Ming; Wu, Jingxian; Hou, Xianyao

    2014-01-01

    Most traditional mode choice models are based on the principle of random utility maximization derived from econometric theory. Alternatively, mode choice modeling can be regarded as a pattern recognition problem reflected from the explanatory variables of determining the choices between alternatives. The paper applies the knowledge discovery technique of rough sets theory to model travel mode choices incorporating household and individual sociodemographics and travel information, and to identify the significance of each attribute. The study uses the detailed travel diary survey data of Changxing county which contains information on both household and individual travel behaviors for model estimation and evaluation. The knowledge is presented in the form of easily understood IF-THEN statements or rules which reveal how each attribute influences mode choice behavior. These rules are then used to predict travel mode choices from information held about previously unseen individuals and the classification performance is assessed. The rough sets model shows high robustness and good predictive ability. The most significant condition attributes identified to determine travel mode choices are gender, distance, household annual income, and occupation. Comparative evaluation with the MNL model also proves that the rough sets model gives superior prediction accuracy and coverage on travel mode choice modeling.

  18. Simulated forecasts for primordial B-mode searches in ground-based experiments

    CERN Document Server

    Alonso, David; Naess, Sigurd; Thorne, Ben

    2016-01-01

    Detecting the imprint of inflationary gravitational waves on the $B$-mode polarization of the Cosmic Microwave Background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of Galactic foregrounds and correlated atmospheric noise. We present forecasts for Stage-3 (S3) and planned Stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially-varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio $r$ caused by an incorrect modelling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on $r$ of the order $\\sigma(r)=(0.5-1.0)\\times10^{-2}$ and $\\sigma(r)=(0.5-1.0)\\times10^{-3}$ respectively, assuming...

  19. Pulse-mode measurement of electron beam halo using diamond-based detector

    Science.gov (United States)

    Aoyagi, Hideki; Asano, Yoshihiro; Itoga, Toshiro; Nariyama, Nobuteru; Bizen, Teruhiko; Tanaka, Takashi; Kitamura, Hideo

    2012-02-01

    Using a diamond-based detector, the electron beam halo in a high-energy accelerator can be measured with a lower detection limit than that using other instruments, such as a core monitor, a dose meter, or an optical fiber. We have successfully measured an electron beam halo using diamond-based detectors operating in the ionization mode, which were installed in the beam duct to measure the intensity of the beam halo directly. Pulse-by-pulse measurements were adopted to suppress the background noise efficiently. Feasibility tests on the diamond-based detector and beam halo monitor were performed in the beam dump area of the 8 GeV SPring-8 synchrotron booster and at the 250 MeV SPring-8 Compact SASE Source test accelerator for the SPring-8 Angstrom Compact free electron LAser (SACLA), respectively. We achieved a lower detection limit of 2×103electrons/pulse for single-shot measurement, which corresponds to a ratio of about 10-6 relative to the typical charge of the beam core of 0.3 pC. We also confirmed the feasibility of the electron beam halo monitor for use as an interlock sensor to protect undulator permanent magnets used in SACLA from radiation damage.

  20. Range accuracy of photon heterodyne detection with laser pulse based on Geiger-mode APD.

    Science.gov (United States)

    Luo, Hanjun; Yuan, XiuHua; Zeng, Yanan

    2013-08-12

    In this paper, we propose a combined system of heterodyne detection with laser pulse and photon counting based on Geiger-mode avalanche photodiode (GM-APD) that is designed to achieve the range of remote non-cooperative target. Based on the heterodyne principle and assuming that the creation of primary electrons in GM-APD is Poisson-distributed, the range accuracy model is established. The factors that influence the range accuracy, namely pulse width, echo intensity, local oscillator (LO) intensity, noise, echo position, and beat frequency, are discussed. The results show that these six factors have significant influence on the range accuracy when the echo intensity is extremely weak. In case that the primary electrons of the echo signal are beyond 4, the pulse width and echo intensity are the main influence factors. It is also shown that the stronger echo intensity, narrower pulse width, low noise, large echo position, and small beat frequency produce higher range accuracy in a pulsed photon heterodyne detection system based on GM-APD.

  1. DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

    Science.gov (United States)

    Raman, N.; Sobha, S.; Selvaganapathy, M.; Mahalakshmi, R.

    2012-10-01

    Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2rad -) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.

  2. Simulated forecasts for primordial B -mode searches in ground-based experiments

    Science.gov (United States)

    Alonso, David; Dunkley, Joanna; Thorne, Ben; Næss, Sigurd

    2017-02-01

    Detecting the imprint of inflationary gravitational waves on the B -mode polarization of the cosmic microwave background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of galactic foregrounds and correlated atmospheric noise. We present forecasts for stage-3 (S3) and planned stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground-cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio r caused by an incorrect modeling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on r of the order σ (r )=(0.5 - 1.0 )×10-2 and σ (r )=(0.5 - 1.0 )×10-3 respectively, assuming instrumental systematic effects are under control. We further study deviations from the fiducial foreground model, finding that, while the effects of a second polarized dust component would be minimal on both S3 and S4, a 2% polarized anomalous dust emission component would be clearly detectable by stage-4 experiments.

  3. A NOVEL INTRUSION DETECTION MODE BASED ON UNDERSTANDABLE NEURAL NETWORK TREES

    Institute of Scientific and Technical Information of China (English)

    Xu Qinzhen; Yang Luxi; Zhao Qiangfu; He Zhenya

    2006-01-01

    Several data mining techniques such as Hidden Markov Model (HMM), artificial neural network,statistical techniques and expert systems are used to model network packets in the field of intrusion detection.In this paper a novel intrusion detection mode based on understandable Neural Network Tree (NNTree) is presented. NNTree is a modular neural network with the overall structure being a Decision Tree (DT), and each non-terminal node being an Expert Neural Network (ENN). One crucial advantage of using NNTrees is that they keep the non-symbolic model ENN's capability of learning in changing environments. Another potential advantage of using NNTrees is that they are actually "gray boxes" as they can be interpreted easily ifthe number of inputs for each ENN is limited. We showed through experiments that the trained NNTree achieved a simple ENN at each non-terminal node as well as a satisfying recognition rate of the network packets dataset.We also compared the performance with that of a three-layer backpropagation neural network. Experimental results indicated that the NNTree based intrusion detection model achieved better performance than the neural network based intrusion detection model.

  4. Pulse-mode measurement of electron beam halo using diamond-based detector

    Directory of Open Access Journals (Sweden)

    Hideki Aoyagi

    2012-02-01

    Full Text Available Using a diamond-based detector, the electron beam halo in a high-energy accelerator can be measured with a lower detection limit than that using other instruments, such as a core monitor, a dose meter, or an optical fiber. We have successfully measured an electron beam halo using diamond-based detectors operating in the ionization mode, which were installed in the beam duct to measure the intensity of the beam halo directly. Pulse-by-pulse measurements were adopted to suppress the background noise efficiently. Feasibility tests on the diamond-based detector and beam halo monitor were performed in the beam dump area of the 8 GeV SPring-8 synchrotron booster and at the 250 MeV SPring-8 Compact SASE Source test accelerator for the SPring-8 Angstrom Compact free electron LAser (SACLA, respectively. We achieved a lower detection limit of 2×10^{3}  electrons/pulse for single-shot measurement, which corresponds to a ratio of about 10^{-6} relative to the typical charge of the beam core of 0.3 pC. We also confirmed the feasibility of the electron beam halo monitor for use as an interlock sensor to protect undulator permanent magnets used in SACLA from radiation damage.

  5. Softening of the elastic shear mode C{sub 66} in iron-based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Anna; Burger, Philipp [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Karlsruher Institut fuer Technologie, Fakultaet fuer Physik, D-76128 Karlsruhe (Germany); Hardy, Frederic; Schweiss, Peter; Fromknecht, Rainer; Wolf, Thomas; Meingast, Christoph [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Reinecker, Marius; Schranz, Wilfried [Universitaet Wien, Fakultaet fuer Physik, A-1090 Wien, Vienna (Austria)

    2013-07-01

    The structural phase transition of underdoped iron-based superconductors is accompanied by a large softening of the elastic shear mode C{sub 66}, which has attracted considerable attention. This softening has been discussed both in terms of orbital and spin-nematic fluctuations which would be responsible for the structural phase transition and, possibly, superconductivity. However, sample requirements have so far restricted experimental investigations of C{sub 66} (via measurements of the ultrasound velocity) to the Ba(Fe,Co){sub 2}As{sub 2} system. Here, we report on a new technique, based on a three-point bending setup, to probe the Young's modulus of a sample with a capacitance dilatometer. For certain orientations, the Young's modulus is related to the elastic constant C{sub 66} whose effective temperature dependence can be obtained. Platelet-like samples, as frequently encountered for iron-based systems, are easily studied with our setup. Data on several systems are presented and discussed.

  6. Individuals' Acceptance to Free-Floating Electric Carsharing Mode: A Web-Based Survey in China.

    Science.gov (United States)

    Wang, Yun; Yan, Xuedong; Zhou, Yu; Xue, Qingwan; Sun, Li

    2017-05-02

    Carsharing is growing rapidly in popularity worldwide. When the vehicles involved are Battery Electric Vehicles (BEV), carsharing has been proven to remarkably contribute to easing energy and environment crises. In this study, individuals' acceptance to carsharing in China was measured from three aspects: carsharing mode choice behavior, highest acceptable price to use carsharing, and willingness to forgo car purchases. The data were collected by a web-based survey. The hierarchical tree-based regression (HTBR) method was applied to explore the effects of potential influencing factors on individuals' acceptance, and some interesting findings were obtained: participants who know about carsharing were more likely to use carsharing, pay higher prices and forgo car purchases; the most competitive trip purpose and trip distance for choosing carsharing were, respectively, business activities and 11-20 km; most participants (47.1%) were willing to pay 1-2 Yuan per minute to use carsharing, and males or participants with higher income-level could accept higher price; and when car purchase restrain policy (CPRP) was carried out in a city or the urban public transport service level (UPTSL) was high, participants were more willing to forgo car purchases. Based on the above findings, corresponding policies were proposed to provide guidance for successful establishment of carsharing in China.

  7. Individuals’ Acceptance to Free-Floating Electric Carsharing Mode: A Web-Based Survey in China

    Science.gov (United States)

    Wang, Yun; Yan, Xuedong; Zhou, Yu; Xue, Qingwan; Sun, Li

    2017-01-01

    Carsharing is growing rapidly in popularity worldwide. When the vehicles involved are Battery Electric Vehicles (BEV), carsharing has been proven to remarkably contribute to easing energy and environment crises. In this study, individuals’ acceptance to carsharing in China was measured from three aspects: carsharing mode choice behavior, highest acceptable price to use carsharing, and willingness to forgo car purchases. The data were collected by a web-based survey. The hierarchical tree-based regression (HTBR) method was applied to explore the effects of potential influencing factors on individuals’ acceptance, and some interesting findings were obtained: participants who know about carsharing were more likely to use carsharing, pay higher prices and forgo car purchases; the most competitive trip purpose and trip distance for choosing carsharing were, respectively, business activities and 11–20 km; most participants (47.1%) were willing to pay 1–2 Yuan per minute to use carsharing, and males or participants with higher income-level could accept higher price; and when car purchase restrain policy (CPRP) was carried out in a city or the urban public transport service level (UPTSL) was high, participants were more willing to forgo car purchases. Based on the above findings, corresponding policies were proposed to provide guidance for successful establishment of carsharing in China. PMID:28468318

  8. Investigating properties of the cardiovascular system using innovative analysis algorithms based on ensemble empirical mode decomposition.

    Science.gov (United States)

    Yeh, Jia-Rong; Lin, Tzu-Yu; Chen, Yun; Sun, Wei-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

    2012-01-01

    Cardiovascular system is known to be nonlinear and nonstationary. Traditional linear assessments algorithms of arterial stiffness and systemic resistance of cardiac system accompany the problem of nonstationary or inconvenience in practical applications. In this pilot study, two new assessment methods were developed: the first is ensemble empirical mode decomposition based reflection index (EEMD-RI) while the second is based on the phase shift between ECG and BP on cardiac oscillation. Both methods utilise the EEMD algorithm which is suitable for nonlinear and nonstationary systems. These methods were used to investigate the properties of arterial stiffness and systemic resistance for a pig's cardiovascular system via ECG and blood pressure (BP). This experiment simulated a sequence of continuous changes of blood pressure arising from steady condition to high blood pressure by clamping the artery and an inverse by relaxing the artery. As a hypothesis, the arterial stiffness and systemic resistance should vary with the blood pressure due to clamping and relaxing the artery. The results show statistically significant correlations between BP, EEMD-based RI, and the phase shift between ECG and BP on cardiac oscillation. The two assessments results demonstrate the merits of the EEMD for signal analysis.

  9. Individuals’ Acceptance to Free-Floating Electric Carsharing Mode: A Web-Based Survey in China

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2017-05-01

    Full Text Available Carsharing is growing rapidly in popularity worldwide. When the vehicles involved are Battery Electric Vehicles (BEV, carsharing has been proven to remarkably contribute to easing energy and environment crises. In this study, individuals’ acceptance to carsharing in China was measured from three aspects: carsharing mode choice behavior, highest acceptable price to use carsharing, and willingness to forgo car purchases. The data were collected by a web-based survey. The hierarchical tree-based regression (HTBR method was applied to explore the effects of potential influencing factors on individuals’ acceptance, and some interesting findings were obtained: participants who know about carsharing were more likely to use carsharing, pay higher prices and forgo car purchases; the most competitive trip purpose and trip distance for choosing carsharing were, respectively, business activities and 11–20 km; most participants (47.1% were willing to pay 1–2 Yuan per minute to use carsharing, and males or participants with higher income-level could accept higher price; and when car purchase restrain policy (CPRP was carried out in a city or the urban public transport service level (UPTSL was high, participants were more willing to forgo car purchases. Based on the above findings, corresponding policies were proposed to provide guidance for successful establishment of carsharing in China.

  10. SVM-Based CAC System for B-Mode Kidney Ultrasound Images.

    Science.gov (United States)

    Subramanya, M B; Kumar, Vinod; Mukherjee, Shaktidev; Saini, Manju

    2015-08-01

    The present study proposes a computer-aided classification (CAC) system for three kidney classes, viz. normal, medical renal disease (MRD) and cyst using B-mode ultrasound images. Thirty-five B-mode kidney ultrasound images consisting of 11 normal images, 8 MRD images and 16 cyst images have been used. Regions of interest (ROIs) have been marked by the radiologist from the parenchyma region of the kidney in case of normal and MRD cases and from regions inside lesions for cyst cases. To evaluate the contribution of texture features extracted from de-speckled images for the classification task, original images have been pre-processed by eight de-speckling methods. Six categories of texture features are extracted. One-against-one multi-class support vector machine (SVM) classifier has been used for the present work. Based on overall classification accuracy (OCA), features from ROIs of original images are concatenated with the features from ROIs of pre-processed images. On the basis of OCA, few feature sets are considered for feature selection. Differential evolution feature selection (DEFS) has been used to select optimal features for the classification task. DEFS process is repeated 30 times to obtain 30 subsets. Run-length matrix features from ROIs of images pre-processed by Lee's sigma concatenated with that of enhanced Lee method have resulted in an average accuracy (in %) and standard deviation of 86.3 ± 1.6. The results obtained in the study indicate that the performance of the proposed CAC system is promising, and it can be used by the radiologists in routine clinical practice for the classification of renal diseases.

  11. Damage detection based on mode shapes of a girder bridge constructed from responses of a moving vehicle under impact excitation

    Science.gov (United States)

    Qi, Zhongqiang; Au, Francis T. K.

    2016-04-01

    The vibration mode shapes are often used to identify damage of bridges because the mode shapes are not only important modal properties but also sensitive to damage. However, the key issue is how to conveniently obtain the mode shapes of a bridge in service. Traditional methods invariably require installation of instruments on the bridge for collection of dynamic responses for constructing mode shapes, which are both costly and inconvenient. Therefore a method is developed to construct the mode shapes of simply supported bridges based on Hilbert Transform using only vehicle acceleration response for identification of the location of damage. Firstly, an algorithm is devised to construct the mode shapes by using the dynamic responses extracted from a moving vehicle under impact excitation. Then, based on these intermediate results, the coordinate modal assurance criterion in conjunction with suitable wavelets is used to identify the location of damage. Compared with the traditional methods, the proposed method uses only the information from the moving vehicle. Moreover, additional impact excitation on the vehicle helps to excite the bridge. This helps to improve the accuracy by overcoming the adverse effects of measurement noise and road surface roughness, which leads to high accuracy of damage detection. To verify the feasibility of the proposed method, some numerical studies have been carried out to investigate the effects of measurement noise, road surface roughness and multiple locations of damage on the accuracy of results.

  12. A Study on the Reform and Further Development of "Chongzhou Mode" Based on the Perspective of Modern Enterprise Management

    Institute of Scientific and Technical Information of China (English)

    Kai YIN; Yue MEN

    2016-01-01

    At present,the domestic agriculture is facing challenges.Farmers’ income is relatively low,and more and more rural young workers are divorced from the countryside to work in the relatively developed areas,which makes agricultural development caught in a vicious circle,so it is difficult to rationally allocate resources and increase industrial vitality.However,the new agricultural system of " Chongzhou Mode" has emerged to indicate a macro direction of agricultural development.In this paper,with " Chongzhou Mode" as the object of study,from the perspective of modern enterprise management,we elaborate some features of this mode such as corporate governance,land transfer cost internalization and human-based management,and explore the role of this mode in promoting employment,Internet +,and reducing market information asymmetry.Finally,we set forth the corresponding recommendations

  13. An ultra-narrow-band optical filter based on whispering-gallery-mode hybrid-microsphere-cavity

    Science.gov (United States)

    Wan, Hongdan; Zhu, Haohan; Liu, Linqian; Xu, Ji; Wang, Jin

    2016-10-01

    We demonstrate an ultra-narrow-band mode-selection method based on a hybrid-microsphere-cavity which consists of a coated silica microsphere. Optical field distribution and narrow-band transmission spectrum of the whispering gallery modes (WGM) are investigated by finite-difference time-domain method. WGM transmission spectra are measured for microsphere and tapered fibers with different diameters. A high refractive index layer coated on the microsphere-cavity make the Q factor increased, the transmission spectrum bandwidth compressed and the side-mode suppression ratio increased. Parameters of the hybrid-microsphere-cavity, namely, the coated shell thickness and its refractive index are optimized under different excitation light source as to investigate the whispering-gallery-modes' transmission spectrum. The 3dB bandwidth of the proposed filter can be less than MHz which will have great potential for applications in all-optical sensing and communication systems.

  14. Characterization of satellite based proxies for estimating nucleation mode particles over South Africa

    Directory of Open Access Journals (Sweden)

    A.-M. Sundström

    2014-10-01

    Full Text Available In this work satellite observations from the NASA's A-Train constellation were used to derive the values of primary emission and regional nucleation proxies over South Africa to estimate the potential for new particle formation. As derived in Kulmala et al. (2011, the satellite based proxies consist of source terms (NO2, SO2 and UV-B radiation, and a sink term describing the pre-existing aerosols. The first goal of this work was to study in detail the use of satellite aerosol optical depth (AOD as a substitute to the in situ based condensation sink (CS. One of the major factors affecting the agreement of CS and AOD was the elevated aerosol layers that increased the value of column integrated AOD but not affected the in situ CS. However, when the AOD in the proxy sink was replaced by an estimate from linear bivariate fit between AOD and CS, the agreement with the actual nucleation mode number concentration improved somewhat. The second goal of the work was to estimate how well the satellite based proxies can predict the potential for new particle formation. For each proxy the highest potential for new particle formation were observed over the Highveld industrial area, where the emissions were high but the sink due to pre-existing aerosols was relatively low. Best agreement between the satellite and in situ based proxies were obtained for NO2/AOD and UV-B/AOD2, whereas proxies including SO2 in the source term had lower correlation. Even though the OMI SO2 boundary layer product showed reasonable spatial pattern and detected the major sources over the study area, some of the known minor point sources were not detected. When defining the satellite proxies only for days when new particle formation event was observed, it was seen that for all the satellite based proxies the event day medians were higher than the entire measurement period median.

  15. Output tracking control of mobile manipulators based on dynamical sliding-mode control

    Institute of Scientific and Technical Information of China (English)

    WU Yuxiang; FENG Ying; HU Yueming

    2007-01-01

    A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investi- gation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajec- tory correctly but also reduce the chattering of sliding-mode control system considerably.

  16. Delamination detection in composite laminates using dispersion change based on mode conversion of Lamb waves

    Science.gov (United States)

    Okabe, Yoji; Fujibayashi, Keiji; Shimazaki, Mamoru; Soejima, Hideki; Ogisu, Toshimichi

    2010-11-01

    A new ultrasonic propagation system has been constructed using macrofiber composite (MFC) actuators and fiber Bragg grating (FBG) sensors. The MFCs and FBGs can be integrated into composite laminates because of their small size and high fracture strain. The developed system can send and receive broadband Lamb waves. In this research, this system was used to detect delamination damage in composite laminates. First, the multiple modes of Lamb waves in a carbon-fiber-reinforced plastic (CFRP) quasi-isotropic laminate were identified by transmitting and receiving the symmetric and antisymmetric modes separately. Then, the mode conversions at both tips of a delamination were investigated through an experiment and a two-dimensional finite element analysis (FEA). A new delamination detection method was proposed on the basis of the mode conversions, and experiments were carried out on laminates with an artificial delamination. When antisymmetric modes were excited, the frequency dispersion of the received A1 mode changed, depending on the delamination length owing to the mode conversion between the A1 mode and the S0 mode. This phenomenon was confirmed through the FEA and these results prove that this new method is effective in detecting a delamination in CFRP laminates.

  17. Communications using multi—mode laser system based on chaotic synchronization

    Institute of Scientific and Technical Information of China (English)

    吴亮; 朱士群; 等

    2003-01-01

    The communication using chaotic synchronization between two multi-mode Nd:YAG lasers has been investigated numerically.The digital communication using multi-mode chatoic lasers is quite different from that using single mode lasers.By introducing a short break between two adjacent bits in the communication shceme,the digital signals can besuccessfully encoded into the spiky pulses and decoded through the subtraction of receiver output from the transmitted.Even when the two multi-mode lasers are not synchronized perfectly with certain deviations,the encoded digits can still be decoded correctly.

  18. Communications using multi-mode laser system based on chaotic synchronization

    Institute of Scientific and Technical Information of China (English)

    吴亮; 朱士群

    2003-01-01

    The communication using chaotic synchronization between two multi-mode Nd:YAG lasers has been investigated numerically. The digital communication using multi-mode chaotic lasers is quite different from that using single mode lasers. By introducing a short break between two adjacent bits in the communication scheme, the digital signals can be successfully encoded into the spiky pulses and decoded through the subtraction of receiver output from the transmitted.Even when the two multi-mode lasers are not synchronized perfectly with certain deviations, the encoded digits can still be decoded correctly.

  19. NEO-INDUSTRIALIZATION IN BASE OF IDEAS OF KNOWLEDGE ECONOMY AND HIGHER TECHNOLOGICAL MODES

    Directory of Open Access Journals (Sweden)

    Lanskaya D. V.

    2015-09-01

    Full Text Available This article has analyzed the contents of the main theories making a modern paradigm of knowledge economy from the point of view of formation of new industrial policy which main contents is neoindustrialization on the basis of the highest technological modes (5th and 6th. Experience of reindustrialization in the countries of Europe, China and the USA is analyzed as well. The article offers an expanded interpretation of import substitution which is neo-industrialization. The research problem consists in creation of theoretical bases and methodology of formation of neoindustrial policy and a neo-industrial complex of knowledge economy in relation to features of the agrarian and industrial region. It is necessary to carry out systemic neo-industrialization for the solution of this task in the all-Russian scale. The wide palette of views of the Russian researchers of neo-industrialization, knowledge economy, the 6th technological mode, spiritual production is analyzed. Among new approaches of mechanisms of realization of neo-industrialization it is possible to allocate: strategic planning; program and target approach; implementation of priority industrial projects of various scale; cluster approach; publicprivate partnership; institutes of development. It has been noted, that the universal mechanism of neo-industrialization is the industrial policy – obligatory attribute of the state participation in economic development of any country. The methodological base of research of a perspective of neo-industrialization is carried out on the bases of evolutionary, synergetic, institutional and resource theories, and the theory of the human capital and a modern paradigm of knowledge economy. The methodological principles of research are offered. Research is conducted using the following main methods: system campaign; system and cognitive method of the analysis of the environment of the region, modeling of elements of strategy of neoindustrialization of

  20. A Novel Fuzzy Logic Based Adaptive Super-Twisting Sliding Mode Control Algorithm for Dynamic Uncertain Systems

    Directory of Open Access Journals (Sweden)

    Abdul Kareem

    2012-07-01

    Full Text Available This paper presents a novel fuzzy logic based Adaptive Super-twisting Sliding Mode Controller for the control of dynamic uncertain systems. The proposed controller combines the advantages of Second order Sliding Mode Control, Fuzzy Logic Control and Adaptive Control. The reaching conditions, stability and robustness of the system with the proposed controller are guaranteed. In addition, the proposed controller is well suited for simple design and implementation. The effectiveness of the proposed controller over the first order Sliding Mode Fuzzy Logic controller is illustrated by Matlab based simulations performed on a DC-DC Buck converter. Based on this comparison, the proposed controller is shown to obtain the desired transient response without causing chattering and error under steady-state conditions. The proposed controller is able to give robust performance in terms of rejection to input voltage variations and load variations.

  1. A Novel Fuzzy Logic Based Adaptive Super-Twisting Sliding Mode Control Algorithm for Dynamic Uncertain Systems

    Directory of Open Access Journals (Sweden)

    Abdul Kareem

    2012-08-01

    Full Text Available This paper presents a novel fuzzy logic based Adaptive Super-twisting Sliding Mode Controller for thecontrol of dynamic uncertain systems. The proposed controller combines the advantages of Second orderSliding Mode Control, Fuzzy Logic Control and Adaptive Control. The reaching conditions, stability androbustness of the system with the proposed controller are guaranteed. In addition, the proposed controlleris well suited for simple design and implementation. The effectiveness of the proposed controller over thefirst order Sliding Mode Fuzzy Logic controller is illustrated by Matlab based simulations performed on aDC-DC Buck converter. Based on this comparison, the proposed controller is shown to obtain the desiredtransient response without causing chattering and error under steady-state conditions. The proposedcontroller is able to give robust performance in terms of rejection to input voltage variations and loadvariations

  2. Sliding mode based trajectory linearization control for hypersonic reentry vehicle via extended disturbance observer.

    Science.gov (United States)

    Xingling, Shao; Honglun, Wang

    2014-11-01

    This paper proposes a novel hybrid control framework by combing observer-based sliding mode control (SMC) with trajectory linearization control (TLC) for hypersonic reentry vehicle (HRV) attitude tracking problem. First, fewer control consumption is achieved using nonlinear tracking differentiator (TD) in the attitude loop. Second, a novel SMC that employs extended disturbance observer (EDO) to counteract the effect of uncertainties using a new sliding surface which includes the estimation error is integrated to address the tracking error stabilization issues in the attitude and angular rate loop, respectively. In addition, new results associated with EDO are examined in terms of dynamic response and noise-tolerant performance, as well as estimation accuracy. The key feature of the proposed compound control approach is that chattering free tracking performance with high accuracy can be ensured for HRV in the presence of multiple uncertainties under control constraints. Based on finite time convergence stability theory, the stability of the resulting closed-loop system is well established. Also, comparisons and extensive simulation results are presented to demonstrate the effectiveness of the control strategy.

  3. The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission.

    Science.gov (United States)

    Kiani, Mehdi; Ghovanloo, Maysam

    2012-09-01

    Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.

  4. Time Domain Strain/Stress Reconstruction Based on Empirical Mode Decomposition: Numerical Study and Experimental Validation.

    Science.gov (United States)

    He, Jingjing; Zhou, Yibin; Guan, Xuefei; Zhang, Wei; Zhang, Weifang; Liu, Yongming

    2016-08-16

    Structural health monitoring has been studied by a number of researchers as well as various industries to keep up with the increasing demand for preventive maintenance routines. This work presents a novel method for reconstruct prompt, informed strain/stress responses at the hot spots of the structures based on strain measurements at remote locations. The structural responses measured from usage monitoring system at available locations are decomposed into modal responses using empirical mode decomposition. Transformation equations based on finite element modeling are derived to extrapolate the modal responses from the measured locations to critical locations where direct sensor measurements are not available. Then, two numerical examples (a two-span beam and a 19956-degree of freedom simplified airfoil) are used to demonstrate the overall reconstruction method. Finally, the present work investigates the effectiveness and accuracy of the method through a set of experiments conducted on an aluminium alloy cantilever beam commonly used in air vehicle and spacecraft. The experiments collect the vibration strain signals of the beam via optical fiber sensors. Reconstruction results are compared with theoretical solutions and a detailed error analysis is also provided.

  5. Time Domain Strain/Stress Reconstruction Based on Empirical Mode Decomposition: Numerical Study and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Jingjing He

    2016-08-01

    Full Text Available Structural health monitoring has been studied by a number of researchers as well as various industries to keep up with the increasing demand for preventive maintenance routines. This work presents a novel method for reconstruct prompt, informed strain/stress responses at the hot spots of the structures based on strain measurements at remote locations. The structural responses measured from usage monitoring system at available locations are decomposed into modal responses using empirical mode decomposition. Transformation equations based on finite element modeling are derived to extrapolate the modal responses from the measured locations to critical locations where direct sensor measurements are not available. Then, two numerical examples (a two-span beam and a 19956-degree of freedom simplified airfoil are used to demonstrate the overall reconstruction method. Finally, the present work investigates the effectiveness and accuracy of the method through a set of experiments conducted on an aluminium alloy cantilever beam commonly used in air vehicle and spacecraft. The experiments collect the vibration strain signals of the beam via optical fiber sensors. Reconstruction results are compared with theoretical solutions and a detailed error analysis is also provided.

  6. Exploring the DNA binding mode of transition metal based biologically active compounds

    Science.gov (United States)

    Raman, N.; Sobha, S.

    2012-01-01

    Few novel 4-aminoantipyrine derived Schiff bases and their metal complexes were synthesized and characterized. Their structural features and other properties were deduced from the elemental analysis, magnetic susceptibility and molar conductivity as well as from mass, IR, UV-vis, 1H NMR and EPR spectral studies. The binding of the complexes with CT-DNA was analyzed by electronic absorption spectroscopy, viscosity measurement, and cyclic voltammetry. The interaction of the metal complexes with DNA was also studied by molecular modeling with special reference to docking. The experimental and docking results revealed that the complexes have the ability of interaction with DNA of minor groove binding mode. The intrinsic binding constants ( Kb) of the complexes with CT-DNA were found out which show that they are minor groove binders. Gel electrophoresis assay demonstrated the ability of the complexes to cleave the pUC19 DNA in the presence of AH 2 (ascorbic acid). Moreover, the oxidative cleavage studies using distamycin revealed the minor groove binding for the newly synthesized 4-aminoantipyrine derived Schiff bases and their metal complexes. Evaluation of antibacterial activity of the complexes against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and Klebsiella pneumoniae exhibited that the complexes have potent biocidal activity than the free ligands.

  7. Knock Detection in Spark Ignition Engines Base on Complementary Ensemble Empirical Mode Decomposition-Hilbert Transform

    Directory of Open Access Journals (Sweden)

    Fengrong Bi

    2016-01-01

    Full Text Available In spark ignition engines, knock onset limits the maximum spark advance. An inaccurate identification of this limit penalises the fuel conversion efficiency. Thus knock feature extraction is the key of closed-loop control of ignition in spark ignition engine. This paper reports an investigation of knock detection in spark ignition (SI engines using CEEMD-Hilbert transform based on the engine cylinder pressure signals and engine cylinder block vibration signals. Complementary Ensemble Empirical Mode Decomposition (CEEMD was used to decompose the signal and detect knock characteristic. Hilbert transform was used to analyze the frequency information of knock characteristic. The result shows that, for both of cylinder pressure signals and vibration signals, the CEEMD algorithm could extract the knock characteristic, and the Hilbert transform result shows that the energy of knock impact areas has the phenomenon of frequency concentration in both cylinder pressure signal and cylinder block vibration signal. At last, the knock window is then determined, based on which a new knock intensity evaluation factor K is propose, and it can accurately distinguish between heavy knock, light knock, and normal combustion three states.

  8. High-performance planar ultrasonic tool based on d₃₁-mode piezocrystal.

    Science.gov (United States)

    Sadiq, Muhammad R; Kuang, Yang; Cochran, Sandy; Huang, Zhihong

    2015-03-01

    Ultrasonic scalpels based on the conventional mass-spring configuration of piezoelectric transducers are widely used in procedures such as oral, hepatic, and pancreatic surgery. However, the weight and self-heating of this configuration are weaknesses. To address these, an alternative approach can be adopted which utilizes a planar configuration of a cutting blade to which piezoelectric drive components are bonded directly. This paper details the design and characterization of three such planar scalpels, made of surgical-grade stainless steel and silicon. These tools operate in the d31 mode configuration, utilizing relaxor-PT single-crystal binary (PMN-PT) and manganese-doped ternary (Mn:PIN-PMN-PT) composition piezoelectric materials. The scalpels, with shapes resembling a dagger, are able to produce longitudinal displacements >5 μm when driven with 20 V(p-p) at their respective resonant frequencies, 73 and 106 kHz. It is observed that both blade and piezoelectric materials significantly affect the performance of the planar tool. The mechanical quality factor, Q(M), of PMNPT based silicon tool is ~1500 in air compared with ~350 for its stainless steel counterpart, and the use of Mn:PIN-PMNPT further increases the Q(M) to ~2400. Furthermore, the study on the effect of various tissue-loading conditions suggest that skin is the most difficult tissue to penetrate, consequently leading to significant reduction in the tool's efficiency and therefore demanding high-Q(M) tools.

  9. Singular Perturbation Theory-Based Qualitative Dynamics Investigation of Flywheel Energy Storage System in Discharge Mode

    Directory of Open Access Journals (Sweden)

    Weiya Zhang

    2014-01-01

    Full Text Available An investigation on qualitative dynamics in a voltage-current dual-loop controlled flywheel energy storage system (FESS operating in discharge mode is presented in this paper, providing novel insights into the effect of two-timescale characteristics on the safety and stability of energy transmission of FESS. Based on singular perturbation theory, a two-timescale approach is proposed to separate the FESS into the fast and slow subsystems. Stability analysis of the transient fixed points confirms the effects of systemic parameters on FESS’s dynamics and indicates that the FESS shifts from the spiking state to the quiescent state when the slow variable crosses the bifurcation point of the fast subsystem. Mechanism analysis reveals that the root cause of the qualitative dynamics is the voltage instability of the FESS. Moreover, the feasibility boundaries of key parameters are derived, and application requirements of the proposed approach are also discussed, guiding the extension of the approach to engineering applications and solving the dynamics analysis problem to some extent at a theoretical analysis level. Constant voltage discharge experiment is performed based on the FESS test bench built in Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, which validates the theoretical results.

  10. Two-Link Flexible Manipulator Control Using Sliding Mode Control Based Linear Matrix Inequality

    Science.gov (United States)

    Zulfatman; Marzuki, Mohammad; Alif Mardiyah, Nur

    2017-04-01

    Two-link flexible manipulator is a manipulator robot which at least one of its arms is made of lightweight material and not rigid. Flexible robot manipulator has some advantages over the rigid robot manipulator, such as lighter, requires less power and costs, and to result greater payload. However, suitable control algorithm to maintain the two-link flexible robot manipulator in accurate positioning is very challenging. In this study, sliding mode control (SMC) was employed as robust control algorithm due to its insensitivity on the system parameter variations and the presence of disturbances when the system states are sliding on a sliding surface. SMC algorithm was combined with linear matrix inequality (LMI), which aims to reduce the effects of chattering coming from the oscillation of the state during sliding on the sliding surface. Stability of the control algorithm is guaranteed by Lyapunov function candidate. Based on simulation works, SMC based LMI resulted in better performance improvements despite the disturbances with significant chattering reduction. This was evident from the decline of the sum of squared tracking error (SSTE) and the sum of squared of control input (SSCI) indexes respectively 25.4% and 19.4%.

  11. A tour-based analysis of travel mode choice accounting for regional transit service

    Institute of Scientific and Technical Information of China (English)

    丁川; 林姚宇; 谢秉磊; 朱晓雨

    2015-01-01

    The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area. With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington−Baltimore Household Travel Survey in 2007, including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors. This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.

  12. Biochemical component identification by light scattering techniques in whispering gallery mode optical resonance based sensor

    Science.gov (United States)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Saetchnikov, Anton V.; Schweiger, Gustav; Ostendorf, Andreas

    2014-03-01

    Experimental data on detection and identification of variety of biochemical agents, such as proteins (albumin, interferon, C reactive protein), microelements (Na+, Ca+), antibiotic of different generations, in both single and multi component solutions under varied in wide range concentration are represented. Analysis has been performed on the light scattering parameters of whispering gallery mode (WGM) optical resonance based sensor with dielectric microspheres from glass and PMMA as sensitive elements fixed by spin - coating techniques in adhesive layer on the surface of substrate or directly on the coupling element. Sensitive layer was integrated into developed fluidic cell with a digital syringe. Light from tuneable laser strict focusing on and scattered by the single microsphere was detected by a CMOS camera. The image was filtered for noise reduction and integrated on two coordinates for evaluation of integrated energy of a measured signal. As the entrance data following signal parameters were used: relative (to a free spectral range) spectral shift of frequency of WGM optical resonance in microsphere and relative efficiency of WGM excitation obtained within a free spectral range which depended on both type and concentration of investigated agents. Multiplexing on parameters and components has been realized using spatial and spectral parameters of scattered by microsphere light with developed data processing. Biochemical component classification and identification of agents under investigation has been performed by network analysis techniques based on probabilistic network and multilayer perceptron. Developed approach is demonstrated to be applicable both for single agent and for multi component biochemical analysis.

  13. PE-CMOS-based C-mode ultrasound: signal acquisition and time gating

    Science.gov (United States)

    Lo, Shih-Chung B.; Liu, Chu-Chuan; Freedman, Matthew T.; Mun, Seong-Ki; Kula, John; Lasser, Marvin E.; Lasser, Bob; Wang, Yue Joseph

    2009-02-01

    Two types of signal acquisition methods using CMOS sensor array coated with piezoelectric material (PE-CMOS) were studied. The laboratory projection-reflection ultrasound prototypes featuring a PE-CMOS ultrasound sensing array and an acoustic compound lens were employed to image pork bones with fractures in vitro. We found that the projection-reflection ultrasound prototypes are capable of revealing hairline bone fractures with skin in tact. However, the image characteristics generated from these C-scan prototypes are somewhat different because they were equipped with two different senor array models. The signal acquired by the first sensor model is based on an integrated signal (IS) at a given time interval. But the signal acquired by the second sensor model is based on peak signal (PS) with a time gating function controllable by the user. We found that both systems can detect bone fracture as small as 0.5mm shown as a strip of ultrasound signal. However, images obtained from the IS sensor show more speckles with a greater blooming effect on the fractures. On the other hand, images obtained from the PS sensor show less contrast with less speckles. When the beam position is slightly tilted from the normal direction, the blooming effect of the ultrasound image would become dark on the fracture region with both acquisition modes.

  14. A Double-Wing Chaotic System Based on Ion Migration Memristor and Its Sliding Mode Control

    Science.gov (United States)

    Min, Guoqi; Duan, Shukai; Wang, Lidan

    The ion migration memristor is a nonlinear element with memory function and nanoscale size, it is considered as a potential candidate to reduce system power consumption and circuit size. When it works as the nonlinear part of the chaotic system, rich nonlinear curves will be produced, and at the same time, the complexity of chaotic systems and the randomness of signals will be enhanced. So in this paper, by Matlab numerical simulation, a new double-wing chaotic system based on an ion migration memristor is designed. In reality, there are many systems interfered inevitably by random noise, so in this paper the random bounded noises are also considered. The power spectrum, Lyapunov exponent spectrum, Poincaré map and bifurcation diagram are used to investigate its complex dynamic characteristics. Then, a SPICE-based analog circuit is presented to verify the feasibility of the system, for which the simulation results are consistent with the numerical simulation. Finally, the sliding mode variable structure control is applied to overcome the shortcomings of traditional control method, so that the chaotic orbits can be controlled to any fixed points or periodic orbits, and this provides an insight into chaos control in power electronics systems.

  15. Analysis of entropies based on empirical mode decomposition in amnesic mild cognitive impairment of diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Dong Cui

    2015-09-01

    Full Text Available EEG characteristics that correlate with the cognitive functions are important in detecting mild cognitive impairment (MCI in T2DM. To investigate the complexity between aMCI group and age-matched non-aMCI control group in T2DM, six entropies combining empirical mode decomposition (EMD, including Approximate entropy (ApEn, Sample entropy (SaEn, Fuzzy entropy (FEn, Permutation entropy (PEn, Power spectrum entropy (PsEn and Wavelet entropy (WEn were used in the study. A feature extraction technique based on maximization of the area under the curve (AUC and a support vector machine (SVM were subsequently used to for features selection and classification. Finally, Pearson's linear correlation was employed to study associations between these entropies and cognitive functions. Compared to other entropies, FEn had a higher classification accuracy, sensitivity and specificity of 68%, 67.1% and 71.9%, respectively. Top 43 salient features achieved classification accuracy, sensitivity and specificity of 73.8%, 72.3% and 77.9%, respectively. P4, T4 and C4 were the highest ranking salient electrodes. Correlation analysis showed that FEn based on EMD was positively correlated to memory at electrodes F7, F8 and P4, and PsEn based on EMD was positively correlated to Montreal cognitive assessment (MoCA and memory at electrode T4. In sum, FEn based on EMD in right-temporal and occipital regions may be more suitable for early diagnosis of the MCI with T2DM.

  16. Study on the Higher Vocational Mode Combining Production with Learning and Research Based on AHP

    Science.gov (United States)

    Li, Yanming; Li, Jin; Zhang, Xiumei

    2009-01-01

    In this article, we applied the AHP method with quantitative analysis and qualitative analysis to analyze three sorts of basic educational mode combining production with learning and research, i.e. the automated instruction, the mode combining production and learning, and the integration combining production with learning and research, and…

  17. Pulse mode actuation-readout system based on MEMS resonator for liquid sensing

    DEFF Research Database (Denmark)

    Tang, Meng; Cagliani, Alberto; Davis, Zachary James

    2014-01-01

    A MEMS (Micro-Electro-Mechanical Systems) bulk disk resonator is applied for mass sensing under its dynamic mode. The classical readout circuitry involves sophisticated feedback loop and feedthrough compensation. We propose a simple straightforward non-loop pulse mode actuation and capacitive rea...

  18. Adaptive Control of MEMS Gyroscope Based on Global Terminal Sliding Mode Controller

    Directory of Open Access Journals (Sweden)

    Weifeng Yan

    2013-01-01

    Full Text Available An adaptive global fast terminal sliding mode control (GFTSM is proposed for tracking control of Micro-Electro-Mechanical Systems (MEMS vibratory gyroscopes under unknown model uncertainties and external disturbances. To improve the convergence rate of reaching the sliding surface, a global fast terminal sliding surface is employed which can integrate the advantages of traditional sliding mode control and terminal sliding mode control. It can be guaranteed that sliding surface and equilibrium point can be reached in a shorter finite time from any initial state. In the presence of unknown upper bound of system nonlinearities, an adaptive global fast terminal sliding mode controller is derived to estimate this unknown upper bound. Simulation results demonstrate that the tracking error can be attenuated efficiently and robustness of the control system can be improved with the proposed adaptive global fast terminal sliding mode control.

  19. Study on flow mode of combined converter for methanol synthesis from coal-based syngas

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhen-ping; MA Hong-fang; YING Wei-yong; FANG Ding-ye

    2011-01-01

    The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established.The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that ifthe flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. Therefore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.

  20. Longitudinal Motion Control of AUV Based on Fuzzy Sliding Mode Method

    Directory of Open Access Journals (Sweden)

    Duo Qi

    2016-01-01

    Full Text Available According to the characteristics of AUV movement, a fuzzy sliding mode controller was designed, in which fuzzy rules were adopted to estimate the switching gain to eliminate disturbance terms and reduce chattering. The six-degree-of-freedom model of AUV was simplified and longitudinal motion equations were established on the basis of previous research. The influences of first-order wave force and torque were taken into consideration. The REMUS was selected to simulate the control effects of conventional sliding mode controller and fuzzy sliding mode controller. Simulation results show that the fuzzy sliding mode controller can meet the requirements and has higher precision and stronger antijamming performances compared with conventional sliding mode controller.

  1. Inversed Vernier effect based single-mode laser emission in coupled microdisks

    CERN Document Server

    Li, Meng; Wang, Kaiyang; Li, Jiankai; Xiao, Shumin; Song, Qinghai

    2015-01-01

    Recently, on-chip single-mode laser emission has attracted considerable research attention due to its wide applications. While most of single-mode lasers in coupled microdisks or microrings have been qualitatively explained by either Vernier effect or inversed Vernier effect, none of them have been experimentally confirmed. Here, we studied the mechanism for single-mode operation in coupled microdisks. We found that the mode numbers had been significantly reduced to nearly single-mode within a large pumping power range from threshold to gain saturation. The detail laser spectra showed that the largest gain and the first lasing peak were mainly generated by one disk and the laser intensity was proportional to the frequency detuning. The corresponding theoretical analysis showed that the experimental observations were dominated by internal coupling within one cavity, which was similar to the recently explored inversed Vernier effect in two coupled microrings. We believe our finding will be important for underst...

  2. Computational Fluid Dynamics (CFD) Simulation of Hypersonic Turbine-Based Combined-Cycle (TBCC) Inlet Mode Transition

    Science.gov (United States)

    Slater, John W.; Saunders, John D.

    2010-01-01

    Methods of computational fluid dynamics were applied to simulate the aerodynamics within the turbine flowpath of a turbine-based combined-cycle propulsion system during inlet mode transition at Mach 4. Inlet mode transition involved the rotation of a splitter cowl to close the turbine flowpath to allow the full operation of a parallel dual-mode ramjet/scramjet flowpath. Steady-state simulations were performed at splitter cowl positions of 0deg, -2deg, -4deg, and -5.7deg, at which the turbine flowpath was closed half way. The simulations satisfied one objective of providing a greater understanding of the flow during inlet mode transition. Comparisons of the simulation results with wind-tunnel test data addressed another objective of assessing the applicability of the simulation methods for simulating inlet mode transition. The simulations showed that inlet mode transition could occur in a stable manner and that accurate modeling of the interactions among the shock waves, boundary layers, and porous bleed regions was critical for evaluating the inlet static and total pressures, bleed flow rates, and bleed plenum pressures. The simulations compared well with some of the wind-tunnel data, but uncertainties in both the windtunnel data and simulations prevented a formal evaluation of the accuracy of the simulation methods.

  3. Research on New Urban Area Planning Based on TOD Mode:A Study on Binhu New District of Hefei City

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    As an urban development mode,the TOD (Transit-oriented Development) mode,targeted at energy-saving and based on the public transportation system,has positive significance for solving problems like disordered urban sprawl and traffic congestion in Chinese cities.This article takes Binhu New District of Hefei as an example to illustrate the practice of the TOD mode in the urban design of large and medium-sized cities.The paper analyzes the relationship between the new district,central urban area,and public transportation development,and puts forward that the TOD mode is suitable for Bihu New District.It states that the TOD mode can be realized through methods such as the building of a "double-rapid" comprehensive public transportation network,the setting up of decentralized-compact urban clusters and TOD communities,the mixevd land-use,as well as the scenery design with complete walking space.The paper also proposes that certain flexible methods can be adopted in order to promote the TOD mode,including making full use of bus transit when rail transit is lacked,setting up TOD communities surrounding the transport hubs,etc.

  4. Identification of surface wave higher modes using a methodology based on seismic noise and coda waves

    Science.gov (United States)

    Rivet, Diane; Campillo, Michel; Sanchez-Sesma, Francisco; Shapiro, Nikolaï M.; Singh, Shri Krishna

    2015-11-01

    Dispersion analysis of Rayleigh waves is performed to assess the velocity of complex structures such as sedimentary basins. At short periods several modes of the Rayleigh waves are often exited. To perform a reliable inversion of the velocity structure an identification of these modes is thus required. We propose a novel method to identify the modes of surface waves. We use the spectral ratio of the ground velocity for the horizontal components over the vertical component (H/V) measured on seismic coda. We then compare the observed values with the theoretical H/V ratio for velocity models deduced from surface wave dispersion when assuming a particular mode. We first invert the Rayleigh wave measurements retrieved from ambient noise cross-correlation with the assumptions that (1) the fundamental mode and (2) the first overtone are excited. Then we use these different velocity models to predict theoretical spectral ratios of the ground velocity for the horizontal components over the vertical component (H/V). These H/V ratios are computed under the hypothesis of equipartition of a diffuse field in a layered medium. Finally we discriminate between fundamental and higher modes by comparing the theoretical H/V ratio with the H/V ratio measured on seismic coda. In an application, we reconstruct Rayleigh waves from cross-correlations of ambient seismic noise recorded at seven broad-band stations in the Valley of Mexico. For paths within the soft quaternary sediments basin, the maximum energy is observed at velocities higher than expected for the fundamental mode. We identify that the dominant mode is the first higher mode, which suggests the importance of higher modes as the main vectors of energy in such complex structures.

  5. An optical wall shear stress sensor based on whispering gallery modes of dielectric microspheres

    Science.gov (United States)

    Ayaz, Ulas Kemal

    In recent years, whispering gallery modes (WGM) of dielectric resonators have received significant attention. Based on this phenomenon, many applications have been proposed ranging from spectroscopy [1], micro-cavity laser technology [2] and optical communications (switching [3], filtering [4] and wavelength division and multiplexing [5]). WGM phenomenon have also been exploited in several sensor concepts such as protein adsorption [6,7], trace gas detection [8], impurity detection in liquids [9], structural health monitoring of composite materials [10], detection of electric fields [11], magnetic fields [12, 13] and temperature [14, 15] as well as mechanical sensing, such as pressure [16] and force [17,18]. A remarkable feature of the WGMs of dielectric microspheres is that they can exhibit extremely high quality factors (Q -factors). In literature, Q-factors as high as ˜10 10 have been reported [19]. In sensor applications, Q-factors determine the resolution of the sensor. Since WGMs of dielectric microspheres exhibit such high Q values, proposed WGM based sensors have extremely good sensing resolutions. In this dissertation, a WGM based wall shear stress sensor that is capable of measuring the shear stress directly is presented. The proposed sensor's feasibility is studied both analytically and experimentally. The experimental study included sensor development, fabrication, calibration, frequency response, dynamic range and proof of concept. The sensor showed that it has potential to measure the shear stress in a wide range of Reynolds numbers. Finally, the sensor is tested in a real flow environment to provide the first direct shear stress measurement in a real flow.

  6. Fully 3D list-mode time-of-flight PET image reconstruction on GPUs using CUDA.

    Science.gov (United States)

    Cui, Jing-Yu; Pratx, Guillem; Prevrhal, Sven; Levin, Craig S

    2011-12-01

    -generated images for all cases. A list-mode ToF OSEM library was developed on the GPU-CUDA platform. Our studies show that the GPU reformulation is considerably faster than a single-threaded reference CPU method especially for ToF processing, while producing virtually identical images. This new method can be easily adapted to enable more advanced algorithms for high resolution PET reconstruction based on additional information such as depth of interaction (DoI), photon energy, and point spread functions (PSFs).

  7. Full-Order Sliding Mode Control for High-Order Nonlinear System Based on Extended State Observer

    Institute of Scientific and Technical Information of China (English)

    CHEN Qiang; TAO Liang; NAN Yurong

    2016-01-01

    In this paper,a full-order sliding mode control based on extended state observer (FSMC+ESO) is proposed for high-order nonlinear system with unknown system states and uncertainties.The extended state observer (ESO) is employed to estimate both the unknown system states and uncertainties so that the restriction that the system states should be completely measurable is relaxed,and a full-order sliding mode controller is designed based on the ESO estimation to overcome the chattering problem existing in ordinary reduced-order sliding mode control.Simulation results show that the proposed method facilitates the practical application with respect to good tracking performance and chattering elimination.

  8. Fractional order sliding-mode control based on parameters auto-tuning for velocity control of permanent magnet synchronous motor.

    Science.gov (United States)

    Zhang, BiTao; Pi, YouGuo; Luo, Ying

    2012-09-01

    A fractional order sliding mode control (FROSMC) scheme based on parameters auto-tuning for the velocity control of permanent magnet synchronous motor (PMSM) is proposed in this paper. The control law of the proposed F(R)OSMC scheme is designed according to Lyapunov stability theorem. Based on the property of transferring energy with adjustable type in F(R)OSMC, this paper analyzes the chattering phenomenon in classic sliding mode control (SMC) is attenuated with F(R)OSMC system. A fuzzy logic inference scheme (FLIS) is utilized to obtain the gain of switching control. Simulations and experiments demonstrate that the proposed FROSMC not only achieve better control performance with smaller chatting than that with integer order sliding mode control, but also is robust to external load disturbance and parameter variations.

  9. An ultra-low crosstalk and broadband two-mode (de)multiplexer based on adiabatic couplers

    Science.gov (United States)

    Sun, Chunlei; Yu, Yu; Ye, Mengyuan; Chen, Guanyu; Zhang, Xinliang

    2016-12-01

    A novel adiabatic couplers (ACs) based broadband and fabrication-tolerant two-mode multiplexer (MUX) is designed using silicon-on-insulator (SOI) platform. Being different from the previously reported ACs-based scheme, the converted and multiplexed signals are on conventional modes, rather than supermodes. The experimental results are in good agreement with the simulations. Over a wavelength range of 75 nm measured, the crosstalk is lower than ‑20 dB, and the insertion loss is ~1 dB. The eye diagram and bit error rate measurements validate the good performance of the proposed mode MUX. The investigation on fabrication tolerance indicates reasonable performance degradation for a large gap deviation from ‑30 to 30 nm and etching depth deviation from ‑50 to 50 nm.

  10. Optical-cell model based on the lasing competition of mode structures with different Q-factors in high-power semiconductor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Podoskin, A. A., E-mail: podoskin@mail.ioffe.ru; Shashkin, I. S.; Slipchenko, S. O.; Pikhtin, N. A.; Tarasov, I. S. [Russian Academy of Sciences, Ioffe Institute (Russian Federation)

    2015-08-15

    A model describing the operation of a completely optical cell, based on the competition of lasing of Fabry-Perot cavity modes and the high-Q closed mode in high-power semiconductor lasers is proposed. Based on rate equations, the conditions of lasing switching between Fabry-Perot modes for ground and excited lasing levels and the closed mode are considered in the case of increasing internal optical loss under conditions of high current pump levels. The optical-cell operation conditions in the mode of a high-power laser radiation switch (reversible mode-structure switching) and in the mode of a memory cell with bistable irreversible lasing switching between mode structures with various Q-factors are considered.

  11. Maximizing negative thermal expansion via rigid unit modes: a geometry-based approach.

    Science.gov (United States)

    Grima, J N; Bajada, M; Scerri, S; Attard, D; Dudek, K K; Gatt, R

    2015-07-08

    Existent rigid unit mode (RUM) models based on rotating squares, which may explain the phenomenon of negative thermal expansion (NTE), are generalized so as to assess the NTE potential for novel systems made from rectangular or rhombic rigid units. Analytical models for the area coefficients of thermal expansion (CTE) of these innovative networks are derived in an attempt to determine the optimal geometrical parameters and connectivity for maximum NTE. It was found that all systems exhibit NTE, the extent of which is determined by the shape and connectivity of the elemental rigid units (side lengths ratio or internal angle). It was also found that some of the networks proposed here should exhibit significantly superior NTE properties when compared with the well-known network of squares, and that for optimal NTE characteristics, pencil-like rigid units should be used rather than square-shaped ones, as these permit larger pore sizes that are more conducive to NTE. All this compliments earlier work on the negative Poisson's ratio (auxetic) potential of such systems and may provide a route for the design of new materials exhibiting superior thermo-mechanical characteristics including specifically tailored CTEs or giant NTE characteristics.

  12. Dual-mode optical microscope based on single-pixel imaging

    Science.gov (United States)

    Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

    2016-07-01

    We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

  13. Sliding mode control of reaction flywheel-based brushless DC motor with buck converter

    Institute of Scientific and Technical Information of China (English)

    Liu Gang; Zhang Cong

    2013-01-01

    Reaction flywheel is a significant actuator for satellites' attitude control.To improve out-put torque and rotational speed accuracy for reaction flywheel,this paper reviews the modeling and control approaches of DC-DC converters and presents an application of the variable structure system theory with associated sliding regimes.Firstly,the topology of reaction flywheel is constructed.The small signal linearization process for a buck converter is illustrated.Then,based on the state averaging models and reaching qualification expressed by the Lee derivative,the general results of the sliding mode control (SMC) are analyzed.The analytical equivalent control laws for reaction flywheel are deduced detailedly by selecting various sliding surfaces at electromotion,energy consumption braking,reverse connection braking stages.Finally,numerical and experimental examples are presented for illustrative purposes.The results demonstrate that favorable agreement is established between the simulations and experiments.The proposed control strategy achieves preferable rotational speed regulation,strong rejection of modest disturbances,and high-precision output torque and rotational speed tracking abilities.

  14. Operating modes of a hydrogen ion source based on a hollow-cathode pulsed Penning discharge

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E. M. [Institute of High Current Electronics, Siberian Branch of Russian Academy of Science, Tomsk (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk (Russian Federation); Shandrikov, M. V., E-mail: shandrikov@opee.hcei.tsc.ru; Vizir, A. V. [Institute of High Current Electronics, Siberian Branch of Russian Academy of Science, Tomsk (Russian Federation)

    2016-02-15

    An ion source based on a hollow-cathode Penning discharge was switched to a high-current pulsed mode (tens of amperes and tens of microseconds) to produce an intense hydrogen ion beam. With molecular hydrogen (H{sub 2}), the ion beam contained three species: H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +}. For all experimental conditions, the fraction of H{sub 2}{sup +} ions in the beam was about 10 ÷ 15% of the total ion beam current and varied little with ion source parameters. At the same time, the ratio of H{sup +} and H{sub 3}{sup +} depended strongly on the discharge current, particularly on its distribution in the gap between the hollow and planar cathodes. Increasing the discharge current increased the H{sup +} fraction in ion beam. The maximum fraction of H{sup +} reached 80% of the total ion beam current. Forced redistribution of the discharge current in the cathode gap for increasing the hollow cathode current could greatly increase the H{sub 3}{sup +} fraction in the beam. At optimum parameters, the fraction of H{sub 3}{sup +} ions reached 60% of the total ion beam current.

  15. PATRICIA, a powerful Cherenkov telescope camera concept based on Geiger-mode-APD light sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Eckart [MPI fuer Physik, Muenchen (Germany); Wagner, Robert [MPI fuer Physik, Muenchen (Germany); Excellence Cluster Universe, Garching (Germany)

    2012-07-01

    We present a concept for a new powerful camera for the 23-m diameter large-size Cherenkov telescopes for the CTA observatory. It is equally suited for any other imaging Cherenkov telescope. PATRICIA (Powerful Atmospheric Telescope Camera for RecordIng Cherenkov LIght with g-Apds) is based on Geiger-mode avalanche photodiodes (G-APD) as light sensors. The camera is split in a sensor plane and both the readout and trigger electronics of the telescope array located in a central container. Analog signals will be transmitted by optical fibers to a readout container. The thin pizzabox-like camera with a 4.5-degree field of view and 0.1-degree pixels will weigh less than a ton and has a considerably lower wind resistance compared to a conventional PMT camera. The camera requires below 1 kW power and simple cooling by Peltier elements is possible. The key light sensor element will be a multi-element G-APD structure of hexagonal shape and 5 sqcm active area, replacing nearly 1:1 the current PMT design. The sensitivity will be at least 1.5 times superior compared to currently proposed PMTs. Importantly, the camera can work at full moonshine, allowing a gain of at least 30-40% in observation time. About 1-2 years of development time is needed.

  16. State observer-based sliding mode control for semi-active hydro-pneumatic suspension

    Science.gov (United States)

    Ren, Hongbin; Chen, Sizhong; Zhao, Yuzhuang; Liu, Gang; Yang, Lin

    2016-02-01

    This paper proposes an improved virtual reference model for semi-active suspension to coordinate the vehicle ride comfort and handling stability. The reference model combines the virtues of sky-hook with ground-hook control logic, and the hybrid coefficient is tuned according to the longitudinal and lateral acceleration so as to improve the vehicle stability especially in high-speed condition. Suspension state observer based on unscented Kalman filter is designed. A sliding mode controller (SMC) is developed to track the states of the reference model. The stability of the SMC strategy is proven by means of Lyapunov function taking into account the nonlinear damper characteristics and sprung mass variation of the vehicle. Finally, the performance of the controller is demonstrated under three typical working conditions: the random road excitation, speed bump road and sharp acceleration and braking. The simulation results indicated that, compared with the traditional passive suspension, the proposed control algorithm can offer a better coordination between vehicle ride comfort and handling stability. This approach provides a viable alternative to costlier active suspension control systems for commercial vehicles.

  17. A novel squeeze mode based magnetorheological valve: design, test and evaluation

    Science.gov (United States)

    Li, Zhihua; Zhang, Xinjie; Guo, Konghui; Ahmadian, Mehdi; Liu, Yang

    2016-12-01

    Magnetorheological (MR) devices have been investigated intensively nowadays, of which MR valve is an important and hot application with the challenges of acquiring high pressure drop within compact configurations. Hence, a novel squeeze mode based MR valve (SMRV) is proposed in this paper, with highlights of high pressure drop and low power consumption within a compact and transplantable structure. SMRV’s characteristics are studied and its core parts are designed including the initial gaps, magnetic circuit and returning spring. The uniform-saturation magnetic intensity principle is proposed and a co-simulation optimal platform is developed to optimize magnetic intensity of the SMRV dimensions. Then, a prototype is developed and its steady-state performance is evaluated. The test results demonstrate that a pressure drop of 10.8 MPa and a controllable ratio of 5 at 1.0 A applied current are achieved within a transplantable configuration. Meanwhile, SMRV only consumes 1/400 W control power to dissipate 1 W fluid power and its power-volume consumption rate, P C · V/P D, is 3.3 × 102 mm3, which has a brilliant application prospect in hydraulic or mechatronic systems.

  18. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-10-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions.

  19. Sliding mode control scheme for a jumping robot with multi-joint based on floating basis

    Science.gov (United States)

    Jianjun, Yao; Duotao, Di; Shuang, Gao; Lei, He; Shenghai, Hu

    2012-01-01

    A jumping robot has different jumping characteristics. The emphasis of its motion characteristics is placed on the sagittal plane, and every phase of a whole jumping motion has different constraints, so it is a variable constraint system. Its kinematic and dynamic equations, both of the stance phase and of the flight phase are established. Furthermore, the floating basis method is applied to unify the dynamic equations of the stance phase and the flight phase. The generalised coordinate is found based on the union of the tiptoe translation and the joint variables to obtain dynamic equations with constraints. Since the jumping robot is a strongly coupled system and has great impact when it lands on the ground, a reaching law is applied in the development of sliding mode controller in task space such that the state trajectory starting from anywhere can move towards the switching surface, making the system tracking error converge exponentially to zero. Simulation results demonstrate the efficiency and validity of the proposed control system.

  20. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-01-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions. PMID:27698443

  1. Charge plasma technique based dopingless accumulation mode junctionless cylindrical surrounding gate MOSFET: analog performance improvement

    Science.gov (United States)

    Trivedi, Nitin; Kumar, Manoj; Haldar, Subhasis; Deswal, S. S.; Gupta, Mridula; Gupta, R. S.

    2017-09-01

    A charge plasma technique based dopingless (DL) accumulation mode (AM) junctionless (JL) cylindrical surrounding gate (CSG) MOSFET has been proposed and extensively investigated. Proposed device has no physical junction at source to channel and channel to drain interface. The complete silicon pillar has been considered as undoped. The high free electron density or induced N+ region is designed by keeping the work function of source/drain metal contacts lower than the work function of undoped silicon. Thus, its fabrication complexity is drastically reduced by curbing the requirement of high temperature doping techniques. The electrical/analog characteristics for the proposed device has been extensively investigated using the numerical simulation and are compared with conventional junctionless cylindrical surrounding gate (JL-CSG) MOSFET with identical dimensions. For the numerical simulation purpose ATLAS-3D device simulator is used. The results show that the proposed device is more short channel immune to conventional JL-CSG MOSFET and suitable for faster switching applications due to higher I ON/ I OFF ratio.

  2. Chinese Stock Index Futures Price Fluctuation Analysis and Prediction Based on Complementary Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Ruoyang Chen

    2016-01-01

    Full Text Available Since the CSI 300 index futures officially began trading on April 15, 2010, analysis and predictions of the price fluctuations of Chinese stock index futures prices have become a popular area of active research. In this paper, the Complementary Ensemble Empirical Mode Decomposition (CEEMD method is used to decompose the sequences of Chinese stock index futures prices into residue terms, low-frequency terms, and high-frequency terms to reveal the fluctuation characteristics over different time scales of the sequences. Then, the CEEMD method is combined with the Particle Swarm Optimization (PSO algorithm-based Support Vector Machine (SVM model to forecast Chinese stock index futures prices. The empirical results show that the residue term determines the long-term trend of stock index futures prices. The low-frequency term, which represents medium-term price fluctuations, is mainly affected by policy regulations under the analysis of the Iterated Cumulative Sums of Squares (ICSS algorithm, whereas short-term market disequilibrium, which is represented by the high-frequency term, plays an important local role in stock index futures price fluctuations. In addition, in forecasting the daily or even intraday price data of Chinese stock index futures, the combination prediction model is superior to the single SVM model, which implies that the accuracy of predicting Chinese stock index futures prices will be improved by considering fluctuation characteristics in different time scales.

  3. Extra-short He-Ne lasers based on mode split

    Institute of Scientific and Technical Information of China (English)

    韩艳梅; 张书练; 李克兰

    1996-01-01

    An extra-short He-Ne laser (shorter than 100mm) does not work well because there is likely no longitudinal mode in the lasing bandwidth sometimes and the output power rises and falls deeply from time to time.A method to solve this problem has been presented and investigated.A piece of quartz crystal plate appropriately designed is used as a cavity mirror of a He-Ne laser,which has a longitudinal mode spacing larger than the lasing bandwidth to make the equal-spacing mode split.In other words,the number of longitudinal modes is doubled and the actual mode spacing is reduced to the half of that without mode split.Therefore,there is always at least one mode operating in the lasing bandwidth and the power is stable at any room temperature.Such a laser with 85mm cavity length and 0.24mW output power has been made.

  4. Inversed Vernier effect based single-mode laser emission in coupled microdisks

    Science.gov (United States)

    Li, Meng; Zhang, Nan; Wang, Kaiyang; Li, Jiankai; Xiao, Shumin; Song, Qinghai

    2015-09-01

    Recently, on-chip single-mode laser emissions in coupled microdisks have attracted considerable research attention due to their wide applications. While most of single-mode lasers in coupled microdisks or microrings have been qualitatively explained by either Vernier effect or inversed Vernier effect, none of them have been experimentally confirmed. Here, we studied the mechanism of single-mode laser operation in coupled microdisks. We found that the mode numbers had been significantly reduced to nearly single-mode within a large pumping power range from threshold to gain saturation. The detail laser spectra showed that the largest gain and the first lasing peak were mainly generated by one disk and the laser intensity was proportional to the wavelength detuning of two set of modes. The corresponding theoretical analysis showed that the experimental observations were dominated by internal coupling within one cavity, which was similar to the recently explored inversed Vernier effect in two coupled microrings. We believe our finding will be important for understanding the previous experimental findings and the development of on-chip single-mode laser.

  5. Voltage Mode-to-Current Mode Transformation

    Directory of Open Access Journals (Sweden)

    Tejmal S. Rathore

    2012-10-01

    Full Text Available This paper proposes a procedure for converting a class of Op Amp-, FTFN-, CC- and CFAbased voltage mode circuits to corresponding current mode circuits without requiring any additional circuit elements and finally from Op Amp-based voltage mode circuits to any of the FTFN, CC and CFA current mode circuits. The latter circuits perform better at high frequency than the former ones. The validity of the transformation has been checked on simulated circuits with PSPICE.

  6. Life cycle energy efficiency and environmental impact assessment of bioethanol production from sweet potato based on different production modes.

    Science.gov (United States)

    Zhang, Jun; Jia, Chunrong; Wu, Yi; Xia, Xunfeng; Xi, Beidou; Wang, Lijun; Zhai, Youlong

    2017-01-01

    The bioethanol is playing an increasingly important role in renewable energy in China. Based on the theory of circular economy, integration of different resources by polygeneration is one of the solutions to improve energy efficiency and to reduce environmental impact. In this study, three modes of bioethanol production were selected to evaluate the life cycle energy efficiency and environmental impact of sweet potato-based bioethanol. The results showed that, the net energy ratio was greater than 1 and the value of net energy gain was positive in the three production modes, in which the maximum value appeared in the circular economy mode (CEM). The environment emission mainly occurred to bioethanol conversion unit in the conventional production mode (CPM) and the cogeneration mode (CGM), and eutrophication potential (EP) and global warming potential (GWP) were the most significant environmental impact category. While compared with CPM and CGM, the environmental impact of CEM significantly declined due to increasing recycling, and plant cultivation unit mainly contributed to EP and GWP. And the comprehensive evaluation score of environmental impact decreased by 73.46% and 23.36%. This study showed that CEM was effective in improving energy efficiency, especially in reducing the environmental impact, and it provides a new method for bioethanol production.

  7. H∞ Observer-Based Sliding Mode Control for Uncertain Stochastic Systems with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2013-01-01

    Full Text Available The paper is concerned with sliding mode control for uncertain time-delay systems subjected to input nonlinearity and stochastic perturbations. Using the sliding mode control, a robust law is derived to guarantee the reachability of the sliding surface in a finite time interval. The sufficient conditions on asymptotic stability of the error system and sliding mode dynamics with disturbance attenuation level are presented in terms of linear matrix inequalities (LMIs. Finally, an example is provided to illustrate the efficiency and effectiveness of the proposed method.

  8. Linear analysis of neoclassical tearing mode based on the four-field reduced neoclassical MHD equation

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Atsushi [Kyushu Univ., Interdisciplinary Graduate School of Engineering Sciences, Kasuga, Fukuoka (Japan); Yagi, Masatoshi; Itoh, Sanae-I. [Kyushu Univ., Research Institute for Applied Mechanics, Kasuga, Fukuoka (Japan)

    2003-02-01

    The linear neoclassical tearing mode is investigated using the four-field reduced neoclassical MHD equations, in which the fluctuating ion parallel flow and ion neoclassical viscosity are taken into account. The dependences of the neoclassical tearing mode on collisionality, diamagnetic drift and q profile are investigated. These results are compared with the results from the conventional three-field model. It is shown that the linear neoclassical tearing mode is stabilized by the ion neoclassical viscosity in the banana regime even if {delta}' > 0. (author)

  9. RTDS implementation of an improved sliding mode based inverter controller for PV system.

    Science.gov (United States)

    Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

    2016-05-01

    This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems.

  10. Transient and sustained elementary flux mode networks on a catalytic string-based chemical evolution model.

    Science.gov (United States)

    Pereira, José A

    2014-08-01

    Theoretical models designed to test the metabolism-first hypothesis for prebiotic evolution have yield strong indications about the hypothesis validity but could sometimes use a more extensive identification between model objects and real objects towards a more meaningful interpretation of results. In an attempt to go in that direction, the string-based model SSE ("steady state evolution") was developed, where abstract molecules (strings) and catalytic interaction rules are based on some of the most important features of carbon compounds in biological chemistry. The system is open with a random inflow and outflow of strings but also with a permanent string food source. Although specific catalysis is a key aspect of the model, used to define reaction rules, the focus is on energetics rather than kinetics. Standard energy change tables were constructed and used with standard formation reactions to track energy flows through the interpretation of equilibrium constant values. Detection of metabolic networks on the reaction system was done with elementary flux mode (EFM) analysis. The combination of these model design and analysis options enabled obtaining metabolic and catalytic networks showing several central features of biological metabolism, some more clearly than in previous models: metabolic networks with stepwise synthesis, energy coupling, catalysts regulation, SN2 coupling, redox coupling, intermediate cycling, coupled inverse pathways (metabolic cycling), autocatalytic cycles and catalytic cascades. The results strongly suggest that the main biological metabolism features, including the genotype-phenotype interpretation, are caused by the principles of catalytic systems and are prior to modern genetic systems principles. It also gives further theoretical support to the thesis that the basic features of biologic metabolism are a consequence of the time evolution of a random catalyst search working on an open system with a permanent food source. The importance

  11. Pyrene-based dual-mode fluorescence switches and logic gates that function in solution and film.

    Science.gov (United States)

    Zhou, Weidong; Li, Yongjun; Li, Yuliang; Liu, Huibiao; Wang, Shu; Li, Cuihong; Yuan, Mingjian; Liu, Xiaofeng; Zhu, Daoben

    2006-07-17

    A dual-mode fluorescence switch controlled by external inputs such as protons and metal ions is described, and each state corresponds to a specific fluorescent emission peak. Based on the reversible changes of the fluorescence emission of the switch responding to different external stimuli, the corresponding integrated logic gates and communication networks have been constructed in solid film or in solution.

  12. Experiences in the Application of Project-Based Learning in a Switching-Mode Power Supplies Course

    Science.gov (United States)

    Lamar, D. G.; Miaja, P. F.; Arias, M.; Rodriguez, A.; Rodriguez, M.; Vazquez, A.; Hernando, M. M.; Sebastian, J.

    2012-01-01

    This paper presents the introduction of problem-based learning (PBL) in a power electronics course at the University of Oviedo, Gijon, Spain, by means of two practical projects: the design and construction of a switching-mode power supply (SMPS) prototype and the static study of a dc-dc converter topology. The goal of this innovation was for…

  13. Optical microcavities based on surface modes in two-dimensional photonic crystals and silicon-on-insulator photonic crystals

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Qiu, M.

    2007-01-01

    Surface-mode optical microcavities based on two-dimensional photonic crystals and silicon-on-insulator photonic crystals are studied. We demonstrate that a high-quality-factor microcavity can be easily realized in these structures. With an increasing of the cavity length, the quality factor is gr...

  14. A novel vibration mode testing method for cylindrical resonators based on microphones.

    Science.gov (United States)

    Zhang, Yongmeng; Wu, Yulie; Wu, Xuezhong; Xi, Xiang; Wang, Jianqiu

    2015-01-16

    Non-contact testing is an important method for the study of the vibrating characteristic of cylindrical resonators. For the vibratory cylinder gyroscope excited by piezo-electric electrodes, mode testing of the cylindrical resonator is difficult. In this paper, a novel vibration testing method for cylindrical resonators is proposed. This method uses a MEMS microphone, which has the characteristics of small size and accurate directivity, to measure the vibration of the cylindrical resonator. A testing system was established, then the system was used to measure the vibration mode of the resonator. The experimental results show that the orientation resolution of the node of the vibration mode is better than 0.1°. This method also has the advantages of low cost and easy operation. It can be used in vibration testing and provide accurate results, which is important for the study of the vibration mode and thermal stability of vibratory cylindrical gyroscopes.

  15. VDCC Based Dual-Mode Quadrature Sinusoidal Oscillator with Outputs at Appropriate Impedance Levels

    Directory of Open Access Journals (Sweden)

    Mayank Srivastava

    2016-01-01

    Full Text Available This article presents a new dual-mode (i.e. both current-mode and voltage-mode quadrature sinusoidal oscillator using two Voltage Differencing Current Conveyors (VDCCs, two resistors and two capacitors. The proposed configuration use only grounded passive elements and enjoys independent resistor/electronic tuning of both Condition of Oscillation (CO as well as Frequency of Oscillation (FO. The quadrature current and voltage mode outputs of this circuit are available at appropriate impedance terminals. The behavior of presented oscillator is also examined under non ideal/parasitic conditions. The validity of the proposed configuration has been confirmed by SPICE simulations with TSMC 0.18μm process parameters.

  16. A Novel Vibration Mode Testing Method for Cylindrical Resonators Based on Microphones

    Directory of Open Access Journals (Sweden)

    Yongmeng Zhang

    2015-01-01

    Full Text Available Non-contact testing is an important method for the study of the vibrating characteristic of cylindrical resonators. For the vibratory cylinder gyroscope excited by piezo-electric electrodes, mode testing of the cylindrical resonator is difficult. In this paper, a novel vibration testing method for cylindrical resonators is proposed. This method uses a MEMS microphone, which has the characteristics of small size and accurate directivity, to measure the vibration of the cylindrical resonator. A testing system was established, then the system was used to measure the vibration mode of the resonator. The experimental results show that the orientation resolution of the node of the vibration mode is better than 0.1°. This method also has the advantages of low cost and easy operation. It can be used in vibration testing and provide accurate results, which is important for the study of the vibration mode and thermal stability of vibratory cylindrical gyroscopes.

  17. Mode-detailed analysis of transmission based directly on Green's functions

    Science.gov (United States)

    Jin, Cailong; Lan, Jin; Zhao, Xuean; Sui, Wenquan

    2016-09-01

    Fisher-Lee relation {bm{t}= {i}bm{Γ}_L^{1/2}bm{G}bm{Γ}^{1/2}_R} t = i Γ L 1 / 2 G Γ R 1 / 2 is a well-established tool to decode the mode information from Green's function and coupling parameters. Using the Bloch eigen-modes of the leads, we show that the {bm{Γ}^{1/2}_{L/R}} Γ L / R 1 / 2 term can be expressed by the Bloch eigen-mode vectors and the wave velocities which give unambiguous algorithm of {bm{Γ}^{1/2}_{L/R}} Γ L / R 1 / 2 in the Fish-Lee relation. Using this approach, we present an accurate and convenient technique to analyze all transport modes and also the dominant channels of an electronic transport system in tight-binding model. We study graphene nanoribbon structures to demonstrate the typical application of our technique.

  18. High frequency optoelectronic oscillators based on the optical feedback of semiconductor mode-locked laser diodes.

    Science.gov (United States)

    Haji, Mohsin; Hou, Lianping; Kelly, Anthony E; Akbar, Jehan; Marsh, John H; Arnold, John M; Ironside, Charles N

    2012-01-30

    Optical self seeding feedback techniques can be used to improve the noise characteristics of passively mode-locked laser diodes. External cavities such as fiber optic cables can increase the memory of the phase and subsequently improve the timing jitter. In this work, an improved optical feedback architecture is proposed using an optical fiber loop delay as a cavity extension of the mode-locked laser. We investigate the effect of the noise reduction as a function of the loop length and feedback power. The well known composite cavity technique is also implemented for suppressing supermode noise artifacts presented due to harmonic mode locking effects. Using this method, we achieve a record low radio frequency linewidth of 192 Hz for any high frequency (>1 GHz) passively mode-locked laser to date (to the best of the authors' knowledge), making it promising for the development of high frequency optoelectronic oscillators.

  19. High Performance Spatial Filter Array Based on Signal Mode Fiber Bundle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Loveraging on Agiltron's experience in optical fiber components, Agiltron proposed a coherent single-mode fiber (SMF) spatial filter array (SFA) with a gradient...

  20. Comparison and Digital Circuit Analysis Based on Low Power Subthreshold Dual Mode Logic

    Directory of Open Access Journals (Sweden)

    D.Naveen Kumar

    2014-03-01

    Full Text Available In this brief, we propose new low power techniques such as Variable body bias method. This technique reduces the leakage power by increasing the body to source voltage of the sleep transistor in the design. By reducing the leakage power overall power of the design is reduced. The proposed logic switches between the active mode and sleep mode. To reduce the leakage current in sleep mode, the body to source voltage of the sleep transistor increased. To increase the voltage of Sleep transistor another transistor is connected to it. Average power and delay are the parameters compared between proposed logic to their CMOS and Dual Mode Logic counter parts in 180-nm process.

  1. A Resonant Mode for Gravitational Wave Detectors based on Atom Interferometry

    CERN Document Server

    Graham, Peter W; Kasevich, Mark A; Rajendran, Surjeet

    2016-01-01

    We describe a new atom interferometric gravitational wave detector design that can operate in a resonant mode for increased sensitivity. By oscillating the positions of the atomic wavepackets, this resonant detection mode allows for coherently enhanced, narrow-band sensitivity at target frequencies. The proposed detector is flexible and can be rapidly switched between broadband and narrow-band detection modes without changing hardware. For instance, a new binary discovered in broadband mode can subsequently be studied further as the inspiral evolves by using a tailored narrow-band detector response. In addition to functioning like a lock-in amplifier for astrophysical events, the enhanced sensitivity of the resonant approach also opens up the possibility of searching for important cosmological signals, including the stochastic gravitational wave background produced by inflation. We give an example of detector parameters which would allow detection of inflationary gravitational waves down to $\\Omega_\\text{GW} ...

  2. Design of passive fault-tolerant controllers of a quadrotor based on sliding mode theory

    National Research Council Canada - National Science Library

    Abdel-Razzak Merheb; Hassan Noura; François Bateman

    2015-01-01

    .... In this configuration, faults are tolerated in the fast inner loop controlling the velocity system. Tuning the controllers to find the optimal values of the sliding mode controller gains is made using the ecological systems algorithm (ESA...

  3. Unusual coordination mode of tetradentate Schiff base cobalt(III) complexes.

    Science.gov (United States)

    Cyriac, Anish; Jeon, Jong Yeob; Varghese, Jobi Kodiyan; Park, Ji Hae; Choi, Soo Young; Chung, Young Keun; Lee, Bun Yeoul

    2012-02-07

    Contrary to the stereotype, Jacobsen's catalyst, chiral (salcy)Co(III)OAc adopts an unusual binding mode. The tetradentate {ONNO} ligand does not form a square plane but wraps cobalt in a cis-β fashion while acetate is chelating.

  4. Spatial mode effects in a cavity EIT-based quantum memory with ion Coulomb crystals

    CERN Document Server

    Zangenberg, Kasper R; Drewsen, Michael

    2012-01-01

    Quantum storage and retrieval of light in ion Coulomb crystals using cavity electromagnetically induced transparency is investigated theoretically. It is found that, when both the control and probe fields are coupled to the same cavity mode, their transverse mode profile affects the quantum memory efficiency in a non-trivial way. Under such conditions the control field parameters and crystal dimensions that maximize the memory efficiency are calculated.

  5. Analytical comparison of circular diaphragm based simple, single and double touch mode - MEMS capacitive pressure sensor

    Science.gov (United States)

    Jindal, Sumit Kumar; Raghuwanshi, Sanjeev Kumar

    2016-03-01

    In this paper a comparative study is done between normal capacitive pressure sensor, a touch mode capacitive pressure sensor and a double touch mode capacitive pressure sensor. The diaphragm in use is of circular shape. The theory and underlying equations has been described for the said devices and then simulations have been done for different performance parameters to understand the advantage of one over the other.

  6. Spatial mode effects in a cavity-EIT based quantum memory with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Zangenberg, Kasper Rothe; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    Quantum storage and retrieval of light in ion Coulomb crystals using cavity electromagnetically induced transparency are investigated theoretically. It is found that when both the control and the probe fields are coupled to the same spatial cavity mode, their transverse mode profile affects the q...... the quantum memory efficiency in a non-trivial way. Under such conditions, the control-field parameters and crystal dimensions that maximize the memory efficiency are calculated....

  7. Singular Value Decomposition-Based Method for Sliding Mode Control and Optimization of Nonlinear Neutral Systems

    OpenAIRE

    Heli Hu; Dan Zhao; Qingling Zhang

    2013-01-01

    The sliding mode control and optimization are investigated for a class of nonlinear neutral systems with the unmatched nonlinear term. In the framework of Lyapunov stability theory, the existence conditions for the designed sliding surface and the stability bound ${\\alpha }^{\\ast }$ are derived via twice transformations. The further results are to develop an efficient sliding mode control law with tuned parameters to attract the state trajectories onto the sliding surface in finit...

  8. A reference station-based GNSS computing mode to support unified precise point positioning and real-time kinematic services

    Science.gov (United States)

    Feng, Yanming; Gu, Shengfeng; Shi, Chuang; Rizos, Chris

    2013-11-01

    Currently, the GNSS computing modes are of two classes: network-based data processing and user receiver-based processing. A GNSS reference receiver station essentially contributes raw measurement data in either the RINEX file format or as real-time data streams in the RTCM format. Very little computation is carried out by the reference station. The existing network-based processing modes, regardless of whether they are executed in real-time or post-processed modes, are centralised or sequential. This paper describes a distributed GNSS computing framework that incorporates three GNSS modes: reference station-based, user receiver-based and network-based data processing. Raw data streams from each GNSS reference receiver station are processed in a distributed manner, i.e., either at the station itself or at a hosting data server/processor, to generate station-based solutions, or reference receiver-specific parameters. These may include precise receiver clock, zenith tropospheric delay, differential code biases, ambiguity parameters, ionospheric delays, as well as line-of-sight information such as azimuth and elevation angles. Covariance information for estimated parameters may also be optionally provided. In such a mode the nearby precise point positioning (PPP) or real-time kinematic (RTK) users can directly use the corrections from all or some of the stations for real-time precise positioning via a data server. At the user receiver, PPP and RTK techniques are unified under the same observation models, and the distinction is how the user receiver software deals with corrections from the reference station solutions and the ambiguity estimation in the observation equations. Numerical tests demonstrate good convergence behaviour for differential code bias and ambiguity estimates derived individually with single reference stations. With station-based solutions from three reference stations within distances of 22-103 km the user receiver positioning results, with various

  9. The Experimental Analysis of Cross-talk Effect for Mixed-mode IC's Based on SOI Structure

    Institute of Scientific and Technical Information of China (English)

    ZHANGGuoyan; HUANGRu; ZHANGXing; WANGYangyuan

    2004-01-01

    The experimental study of cross-talk behavior is presented for mixed-mode integrated circuits based on SOI (Silicon-on-insulator) structure. Different strategies to reduce cross-talk are investigated. The influence of bulk contact, separation distance, the guard ring isolation and mesa isolation on the cross-talk has been compared. At the same time, the effect of load impedance on the cross-talk is also included. The results can serve as a guideline for designing low-noise coupling SOI mixed-mode IC's.

  10. Synchronization of uncertain fractional-order chaotic systems with disturbance based on a fractional terminal sliding mode controller

    Institute of Scientific and Technical Information of China (English)

    Wang Dong-Feng; Zhang Jin-Ying; Wang Xiao-Yan

    2013-01-01

    This paper provides a novel method to synchronize uncertain fractional-order chaotic systems with external disturbance via fractional terminal sliding mode control.Based on Lyapunov stability theory,a new fractional-order switching manifold is proposed,and in order to ensure the occurrence of sliding motion in finite time,a corresponding sliding mode control law is designed.The proposed control scheme is applied to synchronize the fractional-order Lorenz chaotic system and fractional-order Chen chaotic system with uncertainty and external disturbance parameters.The simulation results show the applicability and efficiency of the proposed scheme.

  11. A novel camera type for very high energy gamma-ray astronomy based on Geiger-mode avalanche photodiodes

    CERN Document Server

    Anderhub, H; Biland, A; Boller, A; Braun, I; Bretz, T; Commichau, S; Commichau, V; Dorner, D; Gendotti, A; Grimm, O; von Gunten, H; Hildebrand, D; Horisberger, U; Krähenbühl, T; Kranich, D; Lorenz, E; Lustermann, W; Mannheim, K; Neise, D; Pauss, F; Renker, D; Rhode, W; Rissi, M; Röser, U; Rollke, S; Stark, L S; Stucki, J -P; Viertel, G; Vogler, P; Weitzel, Q

    2009-01-01

    Geiger-mode avalanche photodiodes (G-APD) are promising new sensors for light detection in atmospheric Cherenkov telescopes. In this paper, the design and commissioning of a 36-pixel G-APD prototype camera is presented. The data acquisition is based on the Domino Ring Sampling (DRS2) chip. A sub-nanosecond time resolution has been achieved. Cosmic-ray induced air showers have been recorded using an imaging mirror setup, in a self-triggered mode. This is the first time that such measurements have been carried out with a complete G-APD camera.

  12. A novel camera type for very high energy gamma-ray astronomy based on Geiger-mode avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Anderhub, H; Biland, A; Boller, A; Braun, I; Commichau, S; Commichau, V; Dorner, D; Gendotti, A; Grimm, O; Gunten, H von; Hildebrand, D; Horisberger, U; Kraehenbuehl, T; Kranich, D; Lorenz, E; Lustermann, W [Institute for Particle Physics, ETH Zurich, Schafmattstr. 20, 8093 Zurich (Switzerland); Backes, M; Neise, D [TU Dortmund University, Otto-Hahn-Str. 4, 44227 Dortmund (Germany); Bretz, T; Mannheim, K [University of Wuerzburg Am Hubland, 97074 Wuerzburg (Germany)], E-mail: qweitzel@phys.ethz.ch (and others)

    2009-10-15

    Geiger-mode avalanche photodiodes (G-APD) are promising new sensors for light detection in atmospheric Cherenkov telescopes. In this paper, the design and commissioning of a 36-pixel G-APD prototype camera is presented. The data acquisition is based on the Domino Ring Sampling (DRS2) chip. A sub-nanosecond time resolution has been achieved. Cosmic-ray induced air showers have been recorded using an imaging mirror setup, in a self-triggered mode. This is the first time that such measurements have been carried out with a complete G-APD camera.

  13. Dynamic analysis of large structures with uncertain parameters based on coupling component mode synthesis and perturbation method

    Directory of Open Access Journals (Sweden)

    D. Sarsri

    2016-03-01

    Full Text Available This paper presents a methodological approach to compute the stochastic eigenmodes of large FE models with parameter uncertainties based on coupling of second order perturbation method and component mode synthesis methods. Various component mode synthesis methods are used to optimally reduce the size of the model. The statistical first two moments of dynamic response of the reduced system are obtained by the second order perturbation method. Numerical results illustrating the accuracy and efficiency of the proposed coupled methodological procedures for large FE models with uncertain parameters are presented.

  14. Mode-locked InAs/InP quantum-dash-based DBR laser with monolithically integrated SOA

    Science.gov (United States)

    Joshi, Siddharth; Chimot, Nicolas; Barbet, Sophie; Accard, Alain; Lelarge, François

    2014-02-01

    We present the first demonstration of InAs/InP Quantum Dash based single-section frequency comb generator designed for use in photonic integrated circuits. The laser cavity is closed using a specific Bragg reflector without compromising the mode-locking performance of the laser. This enables the integration of single-section mode- locked laser on photonic integrated circuits as on-chip frequency comb source. As a demonstration, we integrate the Fabry Perot laser with a semiconductor optical amplifier. Such a device could be used for amplification or modulation of the frequency generated comb. We thus investigate the device operation to obtain a NRZ modulated comb.

  15. Raman and surface-enhanced Raman spectroscopy of amino acids and nucleotide bases for target bacterial vibrational mode identification

    Science.gov (United States)

    Guicheteau, Jason; Argue, Leanne; Hyre, Aaron; Jacobson, Michele; Christesen, Steven D.

    2006-05-01

    Raman and surface-enhanced Raman spectroscopy (SERS) studies of bacteria have reported a wide range of vibrational mode assignments associated with biological material. We present Raman and SER spectra of the amino acids phenylalanine, tyrosine, tryptophan, glutamine, cysteine, alanine, proline, methionine, asparagine, threonine, valine, glycine, serine, leucine, isoleucine, aspartic acid and glutamic acid and the nucleic acid bases adenosine, guanosine, thymidine, and uridine to better characterize biological vibrational mode assignments for bacterial target identification. We also report spectra of the bacteria Bacillus globigii, Pantoea agglomerans, and Yersinia rhodei along with band assignments determined from the reference spectra obtained.

  16. [The Study of Characteristics of Cladding-Reduced Coated Long-Period Fiber Grating Based on Mode Transition and Dual Peak Resonance].

    Science.gov (United States)

    Lan, Jin-long; Gu, Zheng-tian

    2015-11-01

    Based on coupled-mode theory, the mode transition of the high-order cladding modes in a coated long-period tiber grating (LPFG) has been studied firstly; the mode transition region and non-mode transition region of high-order cladding modes are divided. The response characteristic of cladding mode effective index with increasing the overlay thickness is analyzed; the shift of resonant wavelength in the mode transition region will be larger than that in the non-mode transition region. Further, the changes of the resonant wavelength of some high-order cladding modes with grating period are investigated when the cladding radius are different, the shift between two resonant wavelengths of dual peak in the mode transition region is bigger than that in non-mode transition region when the cladding radius are uniform. And the shift between two resonant wavelengths of dual peak will be increased by the decrease of the cladding radius in both mode transition and non-mode transition regions. Finally, the response characteristics of film refractive index of coated LPFG are investigated for a high-order cladding mode while the cladding radius are different and the overlay thickness is located in mode transition region and non-transition mode region, then the optimized design scheme is come up with. The higher sensitivity dual-peak sensor of coated LPFG than the traditional dual-peak sensor will be obtained when the overlay thickness and refractive index is located in the mode transition region and the grating period close to the phase matching turning points. Further, the resolution power of coated LPFG sensor will further be improved by the appropriate reducing of the cladding radius.

  17. Estimation of aerosol complex refractive indices for both fine and coarse modes simultaneously based on AERONET remote sensing products

    Science.gov (United States)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Li, Donghui; Qie, Lili; Che, Huizheng; Xu, Hua

    2017-09-01

    Climate change assessment, especially model evaluation, requires a better understanding of complex refractive indices (CRIs) of atmospheric aerosols - separately for both fine and coarse modes. However, the widely used aerosol CRI obtained by the global Aerosol Robotic Network (AERONET) corresponds to total-column aerosol particles without separation for fine and coarse modes. This paper establishes a method to separate CRIs of fine and coarse particles based on AERONET volume particle size distribution (VPSD), aerosol optical depth (AOD) and absorbing AOD (AAOD). The method consists of two steps. First a multimodal log-normal distribution that best approximates the AERONET VPSD is found. Then the fine and coarse mode CRIs are found by iterative fitting of AERONET AODs to Mie calculations. The numerical experiment shows good performance for typical water-soluble, biomass burning and dust aerosol types, and the estimated uncertainties on the retrieved sub-mode CRIs are about 0.11 (real part) and 78 % (imaginary part). The 1-year measurements at the AERONET Beijing site are processed, and we obtain CRIs of 1.48-0.010i (imaginary part at 440 nm is 0.012) for fine mode particles and 1.49-0.004i (imaginary part at 440 nm is 0.007) for coarse mode particles, for the period of 2014-2015. Our results also suggest that both fine and coarse aerosol mode CRIs have distinct seasonal characteristics; in particular, CRIs of fine particles in winter season are significantly higher than summer due to possible anthropogenic influences.

  18. FUZZY GLOBAL SLIDING MODE CONTROL BASED ON GENETIC ALGORITHM AND ITS APPLICATION FOR FLIGHT SIMULATOR SERVO SYSTEM

    Institute of Scientific and Technical Information of China (English)

    LIU Jinkun; HE Yuzhu

    2007-01-01

    To alleviate the chattering problem, a new type of fuzzy global sliding mode controller (FGSMC) is presented. In this controller, the switching gain is estimated by fuzzy logic system based on the reachable conditions of sliding mode controller(SMC), and genetic algorithm (GA) is used to optimize scaling factor of the switching gain, thus the switch chattering of SMC can be alleviated.Moreover, global sliding mode is realized by designing an exponential dynamic sliding surface.Simulation and real-time application for flight simulator servo system with Lugre friction are given to indicate that the proposed controller can guarantee high robust performance all the time and can alleviate chattering phenomenon effectively.

  19. A Preliminary Study on Mechanisms of Well Water Temperature Responses Based on the Modes of Stress Loading

    Institute of Scientific and Technical Information of China (English)

    Chen Daqing; Wan Yongfang

    2011-01-01

    Based on the studies of the predecessors, and contrasting the modes of stress loading with water level and water temperature response characteristics of a well-aquifer system, this paper draws a preliminary conclusion on the mechanisms of water temperature responses in a well caused by three modes of stress loading, i.e. gas escape, heat dispersion and cold water penetration mechanisms for elastic seismic wave stress loading; the fracture seepage mechanism for seismic wave stress loading and the hydrodynamic mechanism for earth tide stress loading and stress-dissipative heat mechanism for long period slow stress loading in the earthquake preparation stage. This paper illustrates the typical observation examples for each mode of stress loading and makes a preliminary study on their mechanisms.

  20. A Novel Method for Mechanical Fault Diagnosis Based on Variational Mode Decomposition and Multikernel Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhongliang Lv

    2016-01-01

    Full Text Available A novel fault diagnosis method based on variational mode decomposition (VMD and multikernel support vector machine (MKSVM optimized by Immune Genetic Algorithm (IGA is proposed to accurately and adaptively diagnose mechanical faults. First, mechanical fault vibration signals are decomposed into multiple Intrinsic Mode Functions (IMFs by VMD. Then the features in time-frequency domain are extracted from IMFs to construct the feature sets of mixed domain. Next, Semisupervised Locally Linear Embedding (SS-LLE is adopted for fusion and dimension reduction. The feature sets with reduced dimension are inputted to the IGA optimized MKSVM for failure mode identification. Theoretical analysis demonstrates that MKSVM can approximate any multivariable function. The global optimal parameter vector of MKSVM can be rapidly identified by IGA parameter optimization. The experiments of mechanical faults show that, compared to traditional fault diagnosis models, the proposed method significantly increases the diagnosis accuracy of mechanical faults and enhances the generalization of its application.