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Sample records for entropy method mem

  1. Maximum entropy method in momentum density reconstruction

    International Nuclear Information System (INIS)

    Dobrzynski, L.; Holas, A.

    1997-01-01

    The Maximum Entropy Method (MEM) is applied to the reconstruction of the 3-dimensional electron momentum density distributions observed through the set of Compton profiles measured along various crystallographic directions. It is shown that the reconstruction of electron momentum density may be reliably carried out with the aid of simple iterative algorithm suggested originally by Collins. A number of distributions has been simulated in order to check the performance of MEM. It is shown that MEM can be recommended as a model-free approach. (author). 13 refs, 1 fig

  2. Precise charge density studies by maximum entropy method

    CERN Document Server

    Takata, M

    2003-01-01

    For the production research and development of nanomaterials, their structural information is indispensable. Recently, a sophisticated analytical method, which is based on information theory, the Maximum Entropy Method (MEM) using synchrotron radiation powder data, has been successfully applied to determine precise charge densities of metallofullerenes and nanochannel microporous compounds. The results revealed various endohedral natures of metallofullerenes and one-dimensional array formation of adsorbed gas molecules in nanochannel microporous compounds. The concept of MEM analysis was also described briefly. (author)

  3. The criteria for selecting a method for unfolding neutron spectra based on the information entropy theory

    International Nuclear Information System (INIS)

    Zhu, Qingjun; Song, Fengquan; Ren, Jie; Chen, Xueyong; Zhou, Bin

    2014-01-01

    To further expand the application of an artificial neural network in the field of neutron spectrometry, the criteria for choosing between an artificial neural network and the maximum entropy method for the purpose of unfolding neutron spectra was presented. The counts of the Bonner spheres for IAEA neutron spectra were used as a database, and the artificial neural network and the maximum entropy method were used to unfold neutron spectra; the mean squares of the spectra were defined as the differences between the desired and unfolded spectra. After the information entropy of each spectrum was calculated using information entropy theory, the relationship between the mean squares of the spectra and the information entropy was acquired. Useful information from the information entropy guided the selection of unfolding methods. Due to the importance of the information entropy, the method for predicting the information entropy using the Bonner spheres' counts was established. The criteria based on the information entropy theory can be used to choose between the artificial neural network and the maximum entropy method unfolding methods. The application of an artificial neural network to unfold neutron spectra was expanded. - Highlights: • Two neutron spectra unfolding methods, ANN and MEM, were compared. • The spectrum's entropy offers useful information for selecting unfolding methods. • For the spectrum with low entropy, the ANN was generally better than MEM. • The spectrum's entropy was predicted based on the Bonner spheres' counts

  4. Maximum entropy method approach to the θ term

    International Nuclear Information System (INIS)

    Imachi, Masahiro; Shinno, Yasuhiko; Yoneyama, Hiroshi

    2004-01-01

    In Monte Carlo simulations of lattice field theory with a θ term, one confronts the complex weight problem, or the sign problem. This is circumvented by performing the Fourier transform of the topological charge distribution P(Q). This procedure, however, causes flattening phenomenon of the free energy f(θ), which makes study of the phase structure unfeasible. In order to treat this problem, we apply the maximum entropy method (MEM) to a Gaussian form of P(Q), which serves as a good example to test whether the MEM can be applied effectively to the θ term. We study the case with flattering as well as that without flattening. In the latter case, the results of the MEM agree with those obtained from the direct application of the Fourier transform. For the former, the MEM gives a smoother f(θ) than that of the Fourier transform. Among various default models investigated, the images which yield the least error do not show flattening, although some others cannot be excluded given the uncertainly related to statistical error. (author)

  5. Imaging VLBI polarimetry data from Active Galactic Nuclei using the Maximum Entropy Method

    Directory of Open Access Journals (Sweden)

    Coughlan Colm P.

    2013-12-01

    Full Text Available Mapping the relativistic jets emanating from AGN requires the use of a deconvolution algorithm to account for the effects of missing baseline spacings. The CLEAN algorithm is the most commonly used algorithm in VLBI imaging today and is suitable for imaging polarisation data. The Maximum Entropy Method (MEM is presented as an alternative with some advantages over the CLEAN algorithm, including better spatial resolution and a more rigorous and unbiased approach to deconvolution. We have developed a MEM code suitable for deconvolving VLBI polarisation data. Monte Carlo simulations investigating the performance of CLEAN and the MEM code on a variety of source types are being carried out. Real polarisation (VLBA data taken at multiple wavelengths have also been deconvolved using MEM, and several of the resulting polarisation and Faraday rotation maps are presented and discussed.

  6. Spectral density analysis of time correlation functions in lattice QCD using the maximum entropy method

    International Nuclear Information System (INIS)

    Fiebig, H. Rudolf

    2002-01-01

    We study various aspects of extracting spectral information from time correlation functions of lattice QCD by means of Bayesian inference with an entropic prior, the maximum entropy method (MEM). Correlator functions of a heavy-light meson-meson system serve as a repository for lattice data with diverse statistical quality. Attention is given to spectral mass density functions, inferred from the data, and their dependence on the parameters of the MEM. We propose to employ simulated annealing, or cooling, to solve the Bayesian inference problem, and discuss the practical issues of the approach

  7. The Maximum Entropy Method for Optical Spectrum Analysis of Real-Time TDDFT

    International Nuclear Information System (INIS)

    Toogoshi, M; Kano, S S; Zempo, Y

    2015-01-01

    The maximum entropy method (MEM) is one of the key techniques for spectral analysis. The major feature is that spectra in the low frequency part can be described by the short time-series data. Thus, we applied MEM to analyse the spectrum from the time dependent dipole moment obtained from the time-dependent density functional theory (TDDFT) calculation in real time. It is intensively studied for computing optical properties. In the MEM analysis, however, the maximum lag of the autocorrelation is restricted by the total number of time-series data. We proposed that, as an improved MEM analysis, we use the concatenated data set made from the several-times repeated raw data. We have applied this technique to the spectral analysis of the TDDFT dipole moment of ethylene and oligo-fluorene with n = 8. As a result, the higher resolution can be obtained, which is closer to that of FT with practically time-evoluted data as the same total number of time steps. The efficiency and the characteristic feature of this technique are presented in this paper. (paper)

  8. Analysis of QCD sum rule based on the maximum entropy method

    International Nuclear Information System (INIS)

    Gubler, Philipp

    2012-01-01

    QCD sum rule was developed about thirty years ago and has been used up to the present to calculate various physical quantities like hadrons. It has been, however, needed to assume 'pole + continuum' for the spectral function in the conventional analyses. Application of this method therefore came across with difficulties when the above assumption is not satisfied. In order to avoid this difficulty, analysis to make use of the maximum entropy method (MEM) has been developed by the present author. It is reported here how far this new method can be successfully applied. In the first section, the general feature of the QCD sum rule is introduced. In section 2, it is discussed why the analysis by the QCD sum rule based on the MEM is so effective. In section 3, the MEM analysis process is described, and in the subsection 3.1 likelihood function and prior probability are considered then in subsection 3.2 numerical analyses are picked up. In section 4, some cases of applications are described starting with ρ mesons, then charmoniums in the finite temperature and finally recent developments. Some figures of the spectral functions are shown. In section 5, summing up of the present analysis method and future view are given. (S. Funahashi)

  9. Application of the maximum entropy method to dynamical fermion simulations

    Science.gov (United States)

    Clowser, Jonathan

    This thesis presents results for spectral functions extracted from imaginary-time correlation functions obtained from Monte Carlo simulations using the Maximum Entropy Method (MEM). The advantages this method are (i) no a priori assumptions or parametrisations of the spectral function are needed, (ii) a unique solution exists and (iii) the statistical significance of the resulting image can be quantitatively analysed. The Gross Neveu model in d = 3 spacetime dimensions (GNM3) is a particularly interesting model to study with the MEM because at T = 0 it has a broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are resonances. Results for the elementary fermion, the Goldstone boson (pion), the sigma, the massive pseudoscalar meson and the symmetric phase resonances are presented. UKQCD Nf = 2 dynamical QCD data is also studied with MEM. Results are compared to those found from the quenched approximation, where the effects of quark loops in the QCD vacuum are neglected, to search for sea-quark effects in the extracted spectral functions. Information has been extract from the difficult axial spatial and scalar as well as the pseudoscalar, vector and axial temporal channels. An estimate for the non-singlet scalar mass in the chiral limit is given which is in agreement with the experimental value of Mao = 985 MeV.

  10. Electronic structure of beta-FeSi sub 2 obtained by maximum entropy method and photoemission spectroscopy

    CERN Document Server

    Kakemoto, H; Makita, Y; Kino, Y; Tsukamoto, T; Shin, S; Wada, S; Tsurumi, T

    2003-01-01

    The electronic structure of beta-FeSi sub 2 was investigated by maximum entropy method (MEM) and photoemission spectroscopy. The electronic structure obtained by MEM using X-ray diffraction data at room temperature (RT) showed covalent bonds of Fe-Si and Si-Si electrons. The photoemission spectra of beta-FeSi sub 2 at RT were changed by incidence photon energies. For photon energies between 50 and 100 eV, resonant photoemission spectra caused by a super Coster-Kronig transition were observed. In order to reduce resonant effect about Fe(3d) for obtained photoemission spectra, difference spectrum between 53 and 57 eV was calculated, and it was compared with ab-initio band calculation and spectra function.

  11. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  12. Maximum Entropy Approach in Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

    Science.gov (United States)

    Farsani, Zahra Amini; Schmid, Volker J

    2017-01-01

    In the estimation of physiological kinetic parameters from Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) data, the determination of the arterial input function (AIF) plays a key role. This paper proposes a Bayesian method to estimate the physiological parameters of DCE-MRI along with the AIF in situations, where no measurement of the AIF is available. In the proposed algorithm, the maximum entropy method (MEM) is combined with the maximum a posterior approach (MAP). To this end, MEM is used to specify a prior probability distribution of the unknown AIF. The ability of this method to estimate the AIF is validated using the Kullback-Leibler divergence. Subsequently, the kinetic parameters can be estimated with MAP. The proposed algorithm is evaluated with a data set from a breast cancer MRI study. The application shows that the AIF can reliably be determined from the DCE-MRI data using MEM. Kinetic parameters can be estimated subsequently. The maximum entropy method is a powerful tool to reconstructing images from many types of data. This method is useful for generating the probability distribution based on given information. The proposed method gives an alternative way to assess the input function from the existing data. The proposed method allows a good fit of the data and therefore a better estimation of the kinetic parameters. In the end, this allows for a more reliable use of DCE-MRI. Schattauer GmbH.

  13. A method for manufacturing a hollow mems structure

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to a method for manufacturing an at least partly hollow MEMS structure. In a first step one or more through-going openings is/are provided in core material. The one or more through-going openings is/are then covered by an etch-stop layer. After this step, a bottom...... further comprises the step of creating bottom and top conductors in the respective bottom and top layers. Finally, excess core material is removed in order to create the at least partly hollow MEMS structure which may include a MEMS inductor....

  14. MEM spectral analysis for predicting influenza epidemics in Japan.

    Science.gov (United States)

    Sumi, Ayako; Kamo, Ken-ichi

    2012-03-01

    The prediction of influenza epidemics has long been the focus of attention in epidemiology and mathematical biology. In this study, we tested whether time series analysis was useful for predicting the incidence of influenza in Japan. The method of time series analysis we used consists of spectral analysis based on the maximum entropy method (MEM) in the frequency domain and the nonlinear least squares method in the time domain. Using this time series analysis, we analyzed the incidence data of influenza in Japan from January 1948 to December 1998; these data are unique in that they covered the periods of pandemics in Japan in 1957, 1968, and 1977. On the basis of the MEM spectral analysis, we identified the periodic modes explaining the underlying variations of the incidence data. The optimum least squares fitting (LSF) curve calculated with the periodic modes reproduced the underlying variation of the incidence data. An extension of the LSF curve could be used to predict the incidence of influenza quantitatively. Our study suggested that MEM spectral analysis would allow us to model temporal variations of influenza epidemics with multiple periodic modes much more effectively than by using the method of conventional time series analysis, which has been used previously to investigate the behavior of temporal variations in influenza data.

  15. Maximum entropy analysis of EGRET data

    DEFF Research Database (Denmark)

    Pohl, M.; Strong, A.W.

    1997-01-01

    EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....

  16. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  17. Bayesian interpretation of Generalized empirical likelihood by maximum entropy

    OpenAIRE

    Rochet , Paul

    2011-01-01

    We study a parametric estimation problem related to moment condition models. As an alternative to the generalized empirical likelihood (GEL) and the generalized method of moments (GMM), a Bayesian approach to the problem can be adopted, extending the MEM procedure to parametric moment conditions. We show in particular that a large number of GEL estimators can be interpreted as a maximum entropy solution. Moreover, we provide a more general field of applications by proving the method to be rob...

  18. A novel prototyping method for die-level monolithic integration of MEMS above-IC

    International Nuclear Information System (INIS)

    Cicek, Paul-Vahe; Zhang, Qing; Saha, Tanmoy; Mahdavi, Sareh; Allidina, Karim; Gamal, Mourad El; Nabki, Frederic

    2013-01-01

    This work presents a convenient and versatile prototyping method for integrating surface-micromachined microelectromechanical systems (MEMS) directly above IC electronics, at the die level. Such localized implementation helps reduce development costs associated with the acquisition of full-sized semiconductor wafers. To demonstrate the validity of this method, variants of an IC-compatible surface-micromachining MEMS process are used to build different MEMS devices above a commercial transimpedance amplifier chip. Subsequent functional assessments for both the electronics and the MEMS indicate that the integration is successful, validating the prototyping methodology presented in this work, as well as the suitability of the selected MEMS technology for above-IC integration. (paper)

  19. Methods for calculating nonconcave entropies

    International Nuclear Information System (INIS)

    Touchette, Hugo

    2010-01-01

    Five different methods which can be used to analytically calculate entropies that are nonconcave as functions of the energy in the thermodynamic limit are discussed and compared. The five methods are based on the following ideas and techniques: (i) microcanonical contraction, (ii) metastable branches of the free energy, (iii) generalized canonical ensembles with specific illustrations involving the so-called Gaussian and Betrag ensembles, (iv) the restricted canonical ensemble, and (v) the inverse Laplace transform. A simple long-range spin model having a nonconcave entropy is used to illustrate each method

  20. Entropy viscosity method for nonlinear conservation laws

    KAUST Repository

    Guermond, Jean-Luc

    2011-05-01

    A new class of high-order numerical methods for approximating nonlinear conservation laws is described (entropy viscosity method). The novelty is that a nonlinear viscosity based on the local size of an entropy production is added to the numerical discretization at hand. This new approach does not use any flux or slope limiters, applies to equations or systems supplemented with one or more entropy inequalities and does not depend on the mesh type and polynomial approximation. Various benchmark problems are solved with finite elements, spectral elements and Fourier series to illustrate the capability of the proposed method. © 2010 Elsevier Inc.

  1. Entropy viscosity method for nonlinear conservation laws

    KAUST Repository

    Guermond, Jean-Luc; Pasquetti, Richard; Popov, Bojan

    2011-01-01

    A new class of high-order numerical methods for approximating nonlinear conservation laws is described (entropy viscosity method). The novelty is that a nonlinear viscosity based on the local size of an entropy production is added to the numerical discretization at hand. This new approach does not use any flux or slope limiters, applies to equations or systems supplemented with one or more entropy inequalities and does not depend on the mesh type and polynomial approximation. Various benchmark problems are solved with finite elements, spectral elements and Fourier series to illustrate the capability of the proposed method. © 2010 Elsevier Inc.

  2. Statistical-mechanical entropy by the thin-layer method

    International Nuclear Information System (INIS)

    Feng, He; Kim, Sung Won

    2003-01-01

    G. Hooft first studied the statistical-mechanical entropy of a scalar field in a Schwarzschild black hole background by the brick-wall method and hinted that the statistical-mechanical entropy is the statistical origin of the Bekenstein-Hawking entropy of the black hole. However, according to our viewpoint, the statistical-mechanical entropy is only a quantum correction to the Bekenstein-Hawking entropy of the black-hole. The brick-wall method based on thermal equilibrium at a large scale cannot be applied to the cases out of equilibrium such as a nonstationary black hole. The statistical-mechanical entropy of a scalar field in a nonstationary black hole background is calculated by the thin-layer method. The condition of local equilibrium near the horizon of the black hole is used as a working postulate and is maintained for a black hole which evaporates slowly enough and whose mass is far greater than the Planck mass. The statistical-mechanical entropy is also proportional to the area of the black hole horizon. The difference from the stationary black hole is that the result relies on a time-dependent cutoff

  3. Entropy viscosity method applied to Euler equations

    International Nuclear Information System (INIS)

    Delchini, M. O.; Ragusa, J. C.; Berry, R. A.

    2013-01-01

    The entropy viscosity method [4] has been successfully applied to hyperbolic systems of equations such as Burgers equation and Euler equations. The method consists in adding dissipative terms to the governing equations, where a viscosity coefficient modulates the amount of dissipation. The entropy viscosity method has been applied to the 1-D Euler equations with variable area using a continuous finite element discretization in the MOOSE framework and our results show that it has the ability to efficiently smooth out oscillations and accurately resolve shocks. Two equations of state are considered: Ideal Gas and Stiffened Gas Equations Of State. Results are provided for a second-order time implicit schemes (BDF2). Some typical Riemann problems are run with the entropy viscosity method to demonstrate some of its features. Then, a 1-D convergent-divergent nozzle is considered with open boundary conditions. The correct steady-state is reached for the liquid and gas phases with a time implicit scheme. The entropy viscosity method correctly behaves in every problem run. For each test problem, results are shown for both equations of state considered here. (authors)

  4. Maximum entropy reconstructions for crystallographic imaging; Cristallographie et reconstruction d`images par maximum d`entropie

    Energy Technology Data Exchange (ETDEWEB)

    Papoular, R

    1997-07-01

    The Fourier Transform is of central importance to Crystallography since it allows the visualization in real space of tridimensional scattering densities pertaining to physical systems from diffraction data (powder or single-crystal diffraction, using x-rays, neutrons, electrons or else). In turn, this visualization makes it possible to model and parametrize these systems, the crystal structures of which are eventually refined by Least-Squares techniques (e.g., the Rietveld method in the case of Powder Diffraction). The Maximum Entropy Method (sometimes called MEM or MaxEnt) is a general imaging technique, related to solving ill-conditioned inverse problems. It is ideally suited for tackling undetermined systems of linear questions (for which the number of variables is much larger than the number of equations). It is already being applied successfully in Astronomy, Radioastronomy and Medical Imaging. The advantages of using MAXIMUM Entropy over conventional Fourier and `difference Fourier` syntheses stem from the following facts: MaxEnt takes the experimental error bars into account; MaxEnt incorporate Prior Knowledge (e.g., the positivity of the scattering density in some instances); MaxEnt allows density reconstructions from incompletely phased data, as well as from overlapping Bragg reflections; MaxEnt substantially reduces truncation errors to which conventional experimental Fourier reconstructions are usually prone. The principles of Maximum Entropy imaging as applied to Crystallography are first presented. The method is then illustrated by a detailed example specific to Neutron Diffraction: the search for proton in solids. (author). 17 refs.

  5. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  6. Mammographic image restoration using maximum entropy deconvolution

    International Nuclear Information System (INIS)

    Jannetta, A; Jackson, J C; Kotre, C J; Birch, I P; Robson, K J; Padgett, R

    2004-01-01

    An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization

  7. Piezoelectric MEMS: Ferroelectric thin films for MEMS applications

    Science.gov (United States)

    Kanno, Isaku

    2018-04-01

    In recent years, piezoelectric microelectromechanical systems (MEMS) have attracted attention as next-generation functional microdevices. Typical applications of piezoelectric MEMS are micropumps for inkjet heads or micro-gyrosensors, which are composed of piezoelectric Pb(Zr,Ti)O3 (PZT) thin films and have already been commercialized. In addition, piezoelectric vibration energy harvesters (PVEHs), which are regarded as one of the key devices for Internet of Things (IoT)-related technologies, are promising future applications of piezoelectric MEMS. Significant features of piezoelectric MEMS are their simple structure and high energy conversion efficiency between mechanical and electrical domains even on the microscale. The device performance strongly depends on the function of the piezoelectric thin films, especially on their transverse piezoelectric properties, indicating that the deposition of high-quality piezoelectric thin films is a crucial technology for piezoelectric MEMS. On the other hand, although the difficulty in measuring the precise piezoelectric coefficients of thin films is a serious obstacle in the research and development of piezoelectric thin films, a simple unimorph cantilever measurement method has been proposed to obtain precise values of the direct or converse transverse piezoelectric coefficient of thin films, and recently this method has become to be the standardized testing method. In this article, I will introduce fundamental technologies of piezoelectric thin films and related microdevices, especially focusing on the deposition of PZT thin films and evaluation methods for their transverse piezoelectric properties.

  8. Entropy for gravitational Chern-Simons terms by squashed cone method

    International Nuclear Information System (INIS)

    Guo, Wu-Zhong; Miao, Rong-Xin

    2016-01-01

    In this paper we investigate the entropy of gravitational Chern-Simons terms for the horizon with non-vanishing extrinsic curvatures, or the holographic entanglement entropy for arbitrary entangling surface. In 3D there is no anomaly of entropy. But the original squashed cone method can not be used directly to get the correct result. For higher dimensions the anomaly of entropy would appear, still, we can not use the squashed cone method directly. That is becasuse the Chern-Simons action is not gauge invariant. To get a reasonable result we suggest two methods. One is by adding a boundary term to recover the gauge invariance. This boundary term can be derived from the variation of the Chern-Simons action. The other one is by using the Chern-Simons relation dΩ_4_n_−_1=tr(R"2"n). We notice that the entropy of tr(R"2"n) is a total derivative locally, i.e. S=ds_C_S. We propose to identify s_C_S with the entropy of gravitational Chern-Simons terms Ω_4_n_−_1. In the first method we could get the correct result for Wald entropy in arbitrary dimension. In the second approach, in addition to Wald entropy, we can also obtain the anomaly of entropy with non-zero extrinsic curvatures. Our results imply that the entropy of a topological invariant, such as the Pontryagin term tr(R"2"n) and the Euler density, is a topological invariant on the entangling surface.

  9. Multi-Level Wavelet Shannon Entropy-Based Method for Single-Sensor Fault Location

    Directory of Open Access Journals (Sweden)

    Qiaoning Yang

    2015-10-01

    Full Text Available In actual application, sensors are prone to failure because of harsh environments, battery drain, and sensor aging. Sensor fault location is an important step for follow-up sensor fault detection. In this paper, two new multi-level wavelet Shannon entropies (multi-level wavelet time Shannon entropy and multi-level wavelet time-energy Shannon entropy are defined. They take full advantage of sensor fault frequency distribution and energy distribution across multi-subband in wavelet domain. Based on the multi-level wavelet Shannon entropy, a method is proposed for single sensor fault location. The method firstly uses a criterion of maximum energy-to-Shannon entropy ratio to select the appropriate wavelet base for signal analysis. Then multi-level wavelet time Shannon entropy and multi-level wavelet time-energy Shannon entropy are used to locate the fault. The method is validated using practical chemical gas concentration data from a gas sensor array. Compared with wavelet time Shannon entropy and wavelet energy Shannon entropy, the experimental results demonstrate that the proposed method can achieve accurate location of a single sensor fault and has good anti-noise ability. The proposed method is feasible and effective for single-sensor fault location.

  10. Explaining the entropy concept and entropy components

    Directory of Open Access Journals (Sweden)

    Marko Popovic

    2018-04-01

    Full Text Available Total entropy of a thermodynamic system consists of two components: thermal entropy due to energy, and residual entropy due to molecular orientation. In this article, a three-step method for explaining entropy is suggested. Step one is to use a classical method to introduce thermal entropy STM as a function of temperature T and heat capacity at constant pressure Cp: STM = ∫(Cp/T dT. Thermal entropy is the entropy due to uncertainty in motion of molecules and vanishes at absolute zero (zero-point energy state. It is also the measure of useless thermal energy that cannot be converted into useful work. The next step is to introduce residual entropy S0 as a function of the number of molecules N and the number of distinct orientations available to them in a crystal m: S0 = N kB ln m, where kB is the Boltzmann constant. Residual entropy quantifies the uncertainty in molecular orientation. Residual entropy, unlike thermal entropy, is independent of temperature and remains present at absolute zero. The third step is to show that thermal entropy and residual entropy add up to the total entropy of a thermodynamic system S: S = S0 + STM. This method of explanation should result in a better comprehension of residual entropy and thermal entropy, as well as of their similarities and differences. The new method was tested in teaching at Faculty of Chemistry University of Belgrade, Serbia. The results of the test show that the new method has a potential to improve the quality of teaching.

  11. Anharmonic thermal vibrations of be metal found in the MEM nuclear density map

    International Nuclear Information System (INIS)

    Takata, Masaki; Sakata, Makoto; Larsen, F.K.; Kumazawa, Shintaro; Iversen, B.B.

    1993-01-01

    A direct observation of the thermal vibrations of Be metal was performed by the Maximum Entropy Method (MEM) using neutron single crystal data. In the previous study, the existence of the small but significant cubic anharmonicity of Be has been found by the conventional least squares refinement of the observed structure factors [Larsen, Lehmann and Merisalo (1980) Acta Cryst. A36, 159-163]. In the present study, the same data were used for the MEM analysis which are comprised of 48 reflections up to sinθ/λ = 1.41A -1 in order to obtain the high resolution nuclear density of Be without using any thermal vibrational model. It was directly visible in the MEM map that not only the cubic terms but also quartic anharmonicities exist in the thermal vibrations of Be nuclei. In order to evaluate thermal parameters of Be including anharmonic terms quantitatively, the least squares refinement of the effective one-particle potential (OPP) parameters up to quartic term was carried out by using the MEM nuclear densities around atomic sites as the data set to be fitted. It was found that the present treatment has a great advantage to decide the most appropriate model of OPP by visually comparing the model with MEM density map. As a result of the least squares refinement, the anharmonic thermal parameters are obtained as α 33 = -0.340(5)[eV/A 3 ], α 40 = 0, β 20 = 9.89(1)[eV/A 4 ] and γ 00 = 0. No other anharmonic term was significant. (author)

  12. Analysis of thermal systems using the entropy balance method

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C L.D.; Fartaj, S A; Fenton, D L [Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering

    1992-04-01

    This study investigates the applicability of the second law of thermodynamics using an entropy balance method to analyse and design thermal systems. As examples, the entropy balance method is used to analyse a single stage chiller system and a single stage heat transformer, both with lithium-bromide/water as the working fluid. The entropy method yields not only the same information as is conveyed by the methods of energy and exergy analysis, but it also predicts clearly the influence of irreversibilities of individual components on the coefficient of performance and its effectiveness, based on the process properties, rather than on ambient conditions. Furthermore, this method is capable of presenting the overall distribution of the heat input by displaying the additional heat required to overcome irreversibility of each component without ambiguity. (Author).

  13. A capacitive CMOS-MEMS sensor designed by multi-physics simulation for integrated CMOS-MEMS technology

    Science.gov (United States)

    Konishi, Toshifumi; Yamane, Daisuke; Matsushima, Takaaki; Masu, Kazuya; Machida, Katsuyuki; Toshiyoshi, Hiroshi

    2014-01-01

    This paper reports the design and evaluation results of a capacitive CMOS-MEMS sensor that consists of the proposed sensor circuit and a capacitive MEMS device implemented on the circuit. To design a capacitive CMOS-MEMS sensor, a multi-physics simulation of the electromechanical behavior of both the MEMS structure and the sensing LSI was carried out simultaneously. In order to verify the validity of the design, we applied the capacitive CMOS-MEMS sensor to a MEMS accelerometer implemented by the post-CMOS process onto a 0.35-µm CMOS circuit. The experimental results of the CMOS-MEMS accelerometer exhibited good agreement with the simulation results within the input acceleration range between 0.5 and 6 G (1 G = 9.8 m/s2), corresponding to the output voltages between 908.6 and 915.4 mV, respectively. Therefore, we have confirmed that our capacitive CMOS-MEMS sensor and the multi-physics simulation will be beneficial method to realize integrated CMOS-MEMS technology.

  14. An Adaptively Accelerated Bayesian Deblurring Method with Entropy Prior

    Directory of Open Access Journals (Sweden)

    Yong-Hoon Kim

    2008-05-01

    Full Text Available The development of an efficient adaptively accelerated iterative deblurring algorithm based on Bayesian statistical concept has been reported. Entropy of an image has been used as a “prior” distribution and instead of additive form, used in conventional acceleration methods an exponent form of relaxation constant has been used for acceleration. Thus the proposed method is called hereafter as adaptively accelerated maximum a posteriori with entropy prior (AAMAPE. Based on empirical observations in different experiments, the exponent is computed adaptively using first-order derivatives of the deblurred image from previous two iterations. This exponent improves speed of the AAMAPE method in early stages and ensures stability at later stages of iteration. In AAMAPE method, we also consider the constraint of the nonnegativity and flux conservation. The paper discusses the fundamental idea of the Bayesian image deblurring with the use of entropy as prior, and the analytical analysis of superresolution and the noise amplification characteristics of the proposed method. The experimental results show that the proposed AAMAPE method gives lower RMSE and higher SNR in 44% lesser iterations as compared to nonaccelerated maximum a posteriori with entropy prior (MAPE method. Moreover, AAMAPE followed by wavelet wiener filtering gives better result than the state-of-the-art methods.

  15. Entropy method of measuring and evaluating periodicity of quasi-periodic trajectories

    Science.gov (United States)

    Ni, Yanshuo; Turitsyn, Konstantin; Baoyin, Hexi; Junfeng, Li

    2018-06-01

    This paper presents a method for measuring the periodicity of quasi-periodic trajectories by applying discrete Fourier transform (DFT) to the trajectories and analyzing the frequency domain within the concept of entropy. Having introduced the concept of entropy, analytical derivation and numerical results indicate that entropies increase as a logarithmic function of time. Periodic trajectories typically have higher entropies, and trajectories with higher entropies mean the periodicities of the motions are stronger. Theoretical differences between two trajectories expressed as summations of trigonometric functions are also derived analytically. Trajectories in the Henon-Heiles system and the circular restricted three-body problem (CRTBP) are analyzed with the indicator entropy and compared with orthogonal fast Lyapunov indicator (OFLI). The results show that entropy is a better tool for discriminating periodicity in quasiperiodic trajectories than OFLI and can detect periodicity while excluding the spirals that are judged as periodic cases by OFLI. Finally, trajectories in the vicinity of 243 Ida and 6489 Golevka are considered as examples, and the numerical results verify these conclusions. Some trajectories near asteroids look irregular, but their higher entropy values as analyzed by this method serve as evidence of frequency regularity in three directions. Moreover, these results indicate that applying DFT to the trajectories in the vicinity of irregular small bodies and calculating their entropy in the frequency domain provides a useful quantitative analysis method for evaluating orderliness in the periodicity of quasi-periodic trajectories within a given time interval.

  16. RELIABILITY ASSESSMENT OF ENTROPY METHOD FOR SYSTEM CONSISTED OF IDENTICAL EXPONENTIAL UNITS

    Institute of Scientific and Technical Information of China (English)

    Sun Youchao; Shi Jun

    2004-01-01

    The reliability assessment of unit-system near two levels is the most important content in the reliability multi-level synthesis of complex systems. Introducing the information theory into system reliability assessment, using the addible characteristic of information quantity and the principle of equivalence of information quantity, an entropy method of data information conversion is presented for the system consisted of identical exponential units. The basic conversion formulae of entropy method of unit test data are derived based on the principle of information quantity equivalence. The general models of entropy method synthesis assessment for system reliability approximate lower limits are established according to the fundamental principle of the unit reliability assessment. The applications of the entropy method are discussed by way of practical examples. Compared with the traditional methods, the entropy method is found to be valid and practicable and the assessment results are very satisfactory.

  17. Entropy in bimolecular simulations: A comprehensive review of atomic fluctuations-based methods.

    Science.gov (United States)

    Kassem, Summer; Ahmed, Marawan; El-Sheikh, Salah; Barakat, Khaled H

    2015-11-01

    Entropy of binding constitutes a major, and in many cases a detrimental, component of the binding affinity in biomolecular interactions. While the enthalpic part of the binding free energy is easier to calculate, estimating the entropy of binding is further more complicated. A precise evaluation of entropy requires a comprehensive exploration of the complete phase space of the interacting entities. As this task is extremely hard to accomplish in the context of conventional molecular simulations, calculating entropy has involved many approximations. Most of these golden standard methods focused on developing a reliable estimation of the conformational part of the entropy. Here, we review these methods with a particular emphasis on the different techniques that extract entropy from atomic fluctuations. The theoretical formalisms behind each method is explained highlighting its strengths as well as its limitations, followed by a description of a number of case studies for each method. We hope that this brief, yet comprehensive, review provides a useful tool to understand these methods and realize the practical issues that may arise in such calculations. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Comparison of transfer entropy methods for financial time series

    Science.gov (United States)

    He, Jiayi; Shang, Pengjian

    2017-09-01

    There is a certain relationship between the global financial markets, which creates an interactive network of global finance. Transfer entropy, a measurement for information transfer, offered a good way to analyse the relationship. In this paper, we analysed the relationship between 9 stock indices from the U.S., Europe and China (from 1995 to 2015) by using transfer entropy (TE), effective transfer entropy (ETE), Rényi transfer entropy (RTE) and effective Rényi transfer entropy (ERTE). We compared the four methods in the sense of the effectiveness for identification of the relationship between stock markets. In this paper, two kinds of information flows are given. One reveals that the U.S. took the leading position when in terms of lagged-current cases, but when it comes to the same date, China is the most influential. And ERTE could provide superior results.

  19. Performance Analysis of Entropy Methods on K Means in Clustering Process

    Science.gov (United States)

    Dicky Syahputra Lubis, Mhd.; Mawengkang, Herman; Suwilo, Saib

    2017-12-01

    K Means is a non-hierarchical data clustering method that attempts to partition existing data into one or more clusters / groups. This method partitions the data into clusters / groups so that data that have the same characteristics are grouped into the same cluster and data that have different characteristics are grouped into other groups.The purpose of this data clustering is to minimize the objective function set in the clustering process, which generally attempts to minimize variation within a cluster and maximize the variation between clusters. However, the main disadvantage of this method is that the number k is often not known before. Furthermore, a randomly chosen starting point may cause two points to approach the distance to be determined as two centroids. Therefore, for the determination of the starting point in K Means used entropy method where this method is a method that can be used to determine a weight and take a decision from a set of alternatives. Entropy is able to investigate the harmony in discrimination among a multitude of data sets. Using Entropy criteria with the highest value variations will get the highest weight. Given this entropy method can help K Means work process in determining the starting point which is usually determined at random. Thus the process of clustering on K Means can be more quickly known by helping the entropy method where the iteration process is faster than the K Means Standard process. Where the postoperative patient dataset of the UCI Repository Machine Learning used and using only 12 data as an example of its calculations is obtained by entropy method only with 2 times iteration can get the desired end result.

  20. Entropy method combined with extreme learning machine method for the short-term photovoltaic power generation forecasting

    International Nuclear Information System (INIS)

    Tang, Pingzhou; Chen, Di; Hou, Yushuo

    2016-01-01

    As the world’s energy problem becomes more severe day by day, photovoltaic power generation has opened a new door for us with no doubt. It will provide an effective solution for this severe energy problem and meet human’s needs for energy if we can apply photovoltaic power generation in real life, Similar to wind power generation, photovoltaic power generation is uncertain. Therefore, the forecast of photovoltaic power generation is very crucial. In this paper, entropy method and extreme learning machine (ELM) method were combined to forecast a short-term photovoltaic power generation. First, entropy method is used to process initial data, train the network through the data after unification, and then forecast electricity generation. Finally, the data results obtained through the entropy method with ELM were compared with that generated through generalized regression neural network (GRNN) and radial basis function neural network (RBF) method. We found that entropy method combining with ELM method possesses higher accuracy and the calculation is faster.

  1. Modeling methods of MEMS micro-speaker with electrostatic working principle

    Science.gov (United States)

    Tumpold, D.; Kaltenbacher, M.; Glacer, C.; Nawaz, M.; Dehé, A.

    2013-05-01

    The market for mobile devices like tablets, laptops or mobile phones is increasing rapidly. Device housings get thinner and energy efficiency is more and more important. Micro-Electro-Mechanical-System (MEMS) loudspeakers, fabricated in complementary metal oxide semiconductor (CMOS) compatible technology merge energy efficient driving technology with cost economical fabrication processes. In most cases, the fabrication of such devices within the design process is a lengthy and costly task. Therefore, the need for computer modeling tools capable of precisely simulating the multi-field interactions is increasing. The accurate modeling of such MEMS devices results in a system of coupled partial differential equations (PDEs) describing the interaction between the electric, mechanical and acoustic field. For the efficient and accurate solution we apply the Finite Element (FE) method. Thereby, we fully take the nonlinear effects into account: electrostatic force, charged moving body (loaded membrane) in an electric field, geometric nonlinearities and mechanical contact during the snap-in case between loaded membrane and stator. To efficiently handle the coupling between the mechanical and acoustic fields, we apply Mortar FE techniques, which allow different grid sizes along the coupling interface. Furthermore, we present a recently developed PML (Perfectly Matched Layer) technique, which allows limiting the acoustic computational domain even in the near field without getting spurious reflections. For computations towards the acoustic far field we us a Kirchhoff Helmholtz integral (e.g, to compute the directivity pattern). We will present simulations of a MEMS speaker system based on a single sided driving mechanism as well as an outlook on MEMS speakers using double stator systems (pull-pull-system), and discuss their efficiency (SPL) and quality (THD) towards the generated acoustic sound.

  2. Gravel Image Segmentation in Noisy Background Based on Partial Entropy Method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Because of wide variation in gray levels and particle dimensions and the presence of many small gravel objects in the background, as well as corrupting the image by noise, it is difficult o segment gravel objects. In this paper, we develop a partial entropy method and succeed to realize gravel objects segmentation. We give entropy principles and fur calculation methods. Moreover, we use minimum entropy error automaticly to select a threshold to segment image. We introduce the filter method using mathematical morphology. The segment experiments are performed by using different window dimensions for a group of gravel image and demonstrates that this method has high segmentation rate and low noise sensitivity.

  3. The maximum-entropy method in superspace

    Czech Academy of Sciences Publication Activity Database

    van Smaalen, S.; Palatinus, Lukáš; Schneider, M.

    2003-01-01

    Roč. 59, - (2003), s. 459-469 ISSN 0108-7673 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : maximum-entropy method, * aperiodic crystals * electron density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.558, year: 2003

  4. Entropy methods for reaction-diffusion equations: slowly growing a-priori bounds

    KAUST Repository

    Desvillettes, Laurent; Fellner, Klemens

    2008-01-01

    In the continuation of [Desvillettes, L., Fellner, K.: Exponential Decay toward Equilibrium via Entropy Methods for Reaction-Diffusion Equations. J. Math. Anal. Appl. 319 (2006), no. 1, 157-176], we study reversible reaction-diffusion equations via entropy methods (based on the free energy functional) for a 1D system of four species. We improve the existing theory by getting 1) almost exponential convergence in L1 to the steady state via a precise entropy-entropy dissipation estimate, 2) an explicit global L∞ bound via interpolation of a polynomially growing H1 bound with the almost exponential L1 convergence, and 3), finally, explicit exponential convergence to the steady state in all Sobolev norms.

  5. An Entropy-Based Network Anomaly Detection Method

    Directory of Open Access Journals (Sweden)

    Przemysław Bereziński

    2015-04-01

    Full Text Available Data mining is an interdisciplinary subfield of computer science involving methods at the intersection of artificial intelligence, machine learning and statistics. One of the data mining tasks is anomaly detection which is the analysis of large quantities of data to identify items, events or observations which do not conform to an expected pattern. Anomaly detection is applicable in a variety of domains, e.g., fraud detection, fault detection, system health monitoring but this article focuses on application of anomaly detection in the field of network intrusion detection.The main goal of the article is to prove that an entropy-based approach is suitable to detect modern botnet-like malware based on anomalous patterns in network. This aim is achieved by realization of the following points: (i preparation of a concept of original entropy-based network anomaly detection method, (ii implementation of the method, (iii preparation of original dataset, (iv evaluation of the method.

  6. Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

    Institute of Scientific and Technical Information of China (English)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations.In this paper,it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed.For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates,it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered.However,the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included,because the total heat into the system of interest is not fixed.An irreversible Carnot cycle and an irreversible Brayton cycle are analysed.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed.

  7. Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

    International Nuclear Information System (INIS)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations. In this paper, it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed. For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates, it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered. However, the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included, because the total heat into the system of interest is not fixed. An irreversible Carnot cycle and an irreversible Brayton cycle are analysed. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed. (general)

  8. Downstream-Conditioned Maximum Entropy Method for Exit Boundary Conditions in the Lattice Boltzmann Method

    Directory of Open Access Journals (Sweden)

    Javier A. Dottori

    2015-01-01

    Full Text Available A method for modeling outflow boundary conditions in the lattice Boltzmann method (LBM based on the maximization of the local entropy is presented. The maximization procedure is constrained by macroscopic values and downstream components. The method is applied to fully developed boundary conditions of the Navier-Stokes equations in rectangular channels. Comparisons are made with other alternative methods. In addition, the new downstream-conditioned entropy is studied and it was found that there is a correlation with the velocity gradient during the flow development.

  9. A Maximum Entropy Method for a Robust Portfolio Problem

    Directory of Open Access Journals (Sweden)

    Yingying Xu

    2014-06-01

    Full Text Available We propose a continuous maximum entropy method to investigate the robustoptimal portfolio selection problem for the market with transaction costs and dividends.This robust model aims to maximize the worst-case portfolio return in the case that allof asset returns lie within some prescribed intervals. A numerical optimal solution tothe problem is obtained by using a continuous maximum entropy method. Furthermore,some numerical experiments indicate that the robust model in this paper can result in betterportfolio performance than a classical mean-variance model.

  10. A Tutorial on the Cross-Entropy Method

    NARCIS (Netherlands)

    de Boer, Pieter-Tjerk; Kroese, Dirk; Mannor, Shie; Rubinstein, Reuven Y.

    The cross-entropy (CE) method is a new generic approach to combinatorial and multi-extremal optimization and rare event simulation. The purpose of this tutorial is to give a gentle introduction to the CE method. We present the CE methodology, the basic algorithm and its modi��?cations, and

  11. Topology optimized RF MEMS switches

    DEFF Research Database (Denmark)

    Philippine, M. A.; Zareie, H.; Sigmund, Ole

    2013-01-01

    Topology optimization is a rigorous and powerful method that should become a standard MEMS design tool - it can produce unique and non-intuitive designs that meet complex objectives and can dramatically improve the performance and reliability of MEMS devices. We present successful uses of topology...

  12. MEMS-based fuel cells with integrated catalytic fuel processor and method thereof

    Science.gov (United States)

    Jankowski, Alan F [Livermore, CA; Morse, Jeffrey D [Martinez, CA; Upadhye, Ravindra S [Pleasanton, CA; Havstad, Mark A [Davis, CA

    2011-08-09

    Described herein is a means to incorporate catalytic materials into the fuel flow field structures of MEMS-based fuel cells, which enable catalytic reforming of a hydrocarbon based fuel, such as methane, methanol, or butane. Methods of fabrication are also disclosed.

  13. Improved Ordinary Measure and Image Entropy Theory based intelligent Copy Detection Method

    Directory of Open Access Journals (Sweden)

    Dengpan Ye

    2011-10-01

    Full Text Available Nowadays, more and more multimedia websites appear in social network. It brings some security problems, such as privacy, piracy, disclosure of sensitive contents and so on. Aiming at copyright protection, the copy detection technology of multimedia contents becomes a hot topic. In our previous work, a new computer-based copyright control system used to detect the media has been proposed. Based on this system, this paper proposes an improved media feature matching measure and an entropy based copy detection method. The Levenshtein Distance was used to enhance the matching degree when using for feature matching measure in copy detection. For entropy based copy detection, we make a fusion of the two features of entropy matrix of the entropy feature we extracted. Firstly,we extract the entropy matrix of the image and normalize it. Then, we make a fusion of the eigenvalue feature and the transfer matrix feature of the entropy matrix. The fused features will be used for image copy detection. The experiments show that compared to use these two kinds of features for image detection singly, using feature fusion matching method is apparent robustness and effectiveness. The fused feature has a high detection for copy images which have been received some attacks such as noise, compression, zoom, rotation and so on. Comparing with referred methods, the method proposed is more intelligent and can be achieved good performance.

  14. Electromagnetic actuation in MEMS switches

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Mátéfi-Tempfli, Mária; Chemnitz, Steffen

    . Electromagnetic actuation is a very promising approach to operate such MEMS and Power MEMS devices, due to the long range, reproducible and strong forces generated by this method, among other advantages. However, the use of electromagnetic actuation in such devices requires the use of thick magnetic films, which...

  15. Implementation of the entropy viscosity method with the discontinuous Galerkin method

    KAUST Repository

    Zingan, Valentin

    2013-01-01

    The notion of entropy viscosity method introduced in Guermond and Pasquetti [21] is extended to the discontinuous Galerkin framework for scalar conservation laws and the compressible Euler equations. © 2012 Elsevier B.V.

  16. On cell entropy inequality for discontinuous Galerkin methods

    Science.gov (United States)

    Jiang, Guangshan; Shu, Chi-Wang

    1993-01-01

    We prove a cell entropy inequality for a class of high order discontinuous Galerkin finite element methods approximating conservation laws, which implies convergence for the one dimensional scalar convex case.

  17. A novel method of calibrating a MEMS inertial reference unit on a turntable under limited working conditions

    Science.gov (United States)

    Lu, Jiazhen; Liang, Shufang; Yang, Yanqiang

    2017-10-01

    Micro-electro-mechanical systems (MEMS) inertial measurement devices tend to be widely used in inertial navigation systems and have quickly emerged on the market due to their characteristics of low cost, high reliability and small size. Calibration is the most effective way to remove the deterministic error of an inertial reference unit (IRU), which in this paper consists of three orthogonally mounted MEMS gyros. However, common testing methods in the lab cannot predict the corresponding errors precisely when the turntable’s working condition is restricted. In this paper, the turntable can only provide a relatively small rotation angle. Moreover, the errors must be compensated exactly because of the great effect caused by the high angular velocity of the craft. To deal with this question, a new method is proposed to evaluate the MEMS IRU’s performance. In the calibration procedure, a one-axis table that can rotate a limited angle in the form of a sine function is utilized to provide the MEMS IRU’s angular velocity. A new algorithm based on Fourier series is designed to calculate the misalignment and scale factor errors. The proposed method is tested in a set of experiments, and the calibration results are compared to a traditional calibration method performed under normal working conditions to verify their correctness. In addition, a verification test in the given rotation speed is implemented for further demonstration.

  18. Bubble Entropy: An Entropy Almost Free of Parameters.

    Science.gov (United States)

    Manis, George; Aktaruzzaman, Md; Sassi, Roberto

    2017-11-01

    Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors. Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation

  19. MEMS packaging

    CERN Document Server

    Hsu , Tai-Ran

    2004-01-01

    MEMS Packaging discusses the prevalent practices and enabling techniques in assembly, packaging and testing of microelectromechanical systems (MEMS). The entire spectrum of assembly, packaging and testing of MEMS and microsystems, from essential enabling technologies to applications in key industries of life sciences, telecommunications and aerospace engineering is covered. Other topics included are bonding and sealing of microcomponents, process flow of MEMS and microsystems packaging, automated microassembly, and testing and design for testing.The Institution of Engineering and Technology is

  20. Entropy methods for diffusive partial differential equations

    CERN Document Server

    Jüngel, Ansgar

    2016-01-01

    This book presents a range of entropy methods for diffusive PDEs devised by many researchers in the course of the past few decades, which allow us to understand the qualitative behavior of solutions to diffusive equations (and Markov diffusion processes). Applications include the large-time asymptotics of solutions, the derivation of convex Sobolev inequalities, the existence and uniqueness of weak solutions, and the analysis of discrete and geometric structures of the PDEs. The purpose of the book is to provide readers an introduction to selected entropy methods that can be found in the research literature. In order to highlight the core concepts, the results are not stated in the widest generality and most of the arguments are only formal (in the sense that the functional setting is not specified or sufficient regularity is supposed). The text is also suitable for advanced master and PhD students and could serve as a textbook for special courses and seminars.

  1. Advancing MEMS Technology Usage through the MUMPS (Multi-User MEMS Processes) Program

    Science.gov (United States)

    Koester, D. A.; Markus, K. W.; Dhuler, V.; Mahadevan, R.; Cowen, A.

    1995-01-01

    In order to help provide access to advanced micro-electro-mechanical systems (MEMS) technologies and lower the barriers for both industry and academia, the Microelectronic Center of North Carolina (MCNC) and ARPA have developed a program which provides users with access to both MEMS processes and advanced electronic integration techniques. The four distinct aspects of this program, the multi-user MEMS processes (MUMP's), the consolidated micro-mechanical element library, smart MEMS, and the MEMS technology network are described in this paper. MUMP's is an ARPA-supported program created to provide inexpensive access to MEMS technology in a multi-user environment. It is both a proof-of-concept and educational tool that aids in the development of MEMS in the domestic community. MUMP's technologies currently include a 3-layer poly-silicon surface micromachining process and LIGA (lithography, electroforming, and injection molding) processes that provide reasonable design flexibility within set guidelines. The consolidated micromechanical element library (CaMEL) is a library of active and passive MEMS structures that can be downloaded by the MEMS community via the internet. Smart MEMS is the development of advanced electronics integration techniques for MEMS through the application of flip chip technology. The MEMS technology network (TechNet) is a menu of standard substrates and MEMS fabrication processes that can be purchased and combined to create unique process flows. TechNet provides the MEMS community greater flexibility and enhanced technology accessibility.

  2. A Method of Rotating Machinery Fault Diagnosis Based on the Close Degree of Information Entropy

    Institute of Scientific and Technical Information of China (English)

    GENG Jun-bao; HUANG Shu-hong; JIN Jia-shan; CHEN Fei; LIU Wei

    2006-01-01

    This paper presents a method of rotating machinery fault diagnosis based on the close degree of information entropy. In the view of the information entropy, we introduce four information entropy features of the rotating machinery, which describe the vibration condition of the machinery. The four features are, respectively, denominated as singular spectrum entropy, power spectrum entropy, wavelet space state feature entropy and wavelet power spectrum entropy. The value scopes of the four information entropy features of the rotating machinery in some typical fault conditions are gained by experiments, which can be acted as the standard features of fault diagnosis. According to the principle of the shorter distance between the more similar models, the decision-making method based on the close degree of information entropy is put forward to deal with the recognition of fault patterns. We demonstrate the effectiveness of this approach in an instance involving the fault pattern recognition of some rotating machinery.

  3. Calibration of High Frequency MEMS Microphones

    Science.gov (United States)

    Shams, Qamar A.; Humphreys, William M.; Bartram, Scott M.; Zuckewar, Allan J.

    2007-01-01

    Understanding and controlling aircraft noise is one of the major research topics of the NASA Fundamental Aeronautics Program. One of the measurement technologies used to acquire noise data is the microphone directional array (DA). Traditional direction array hardware, consisting of commercially available condenser microphones and preamplifiers can be too expensive and their installation in hard-walled wind tunnel test sections too complicated. An emerging micro-machining technology coupled with the latest cutting edge technologies for smaller and faster systems have opened the way for development of MEMS microphones. The MEMS microphone devices are available in the market but suffer from certain important shortcomings. Based on early experiments with array prototypes, it has been found that both the bandwidth and the sound pressure level dynamic range of the microphones should be increased significantly to improve the performance and flexibility of the overall array. Thus, in collaboration with an outside MEMS design vendor, NASA Langley modified commercially available MEMS microphone as shown in Figure 1 to meet the new requirements. Coupled with the design of the enhanced MEMS microphones was the development of a new calibration method for simultaneously obtaining the sensitivity and phase response of the devices over their entire broadband frequency range. Over the years, several methods have been used for microphone calibration. Some of the common methods of microphone calibration are Coupler (Reciprocity, Substitution, and Simultaneous), Pistonphone, Electrostatic actuator, and Free-field calibration (Reciprocity, Substitution, and Simultaneous). Traditionally, electrostatic actuators (EA) have been used to characterize air-condenser microphones for wideband frequency ranges; however, MEMS microphones are not adaptable to the EA method due to their construction and very small diaphragm size. Hence a substitution-based, free-field method was developed to

  4. Current opinion about maximum entropy methods in Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Szymanski, K

    2009-01-01

    Current opinion about Maximum Entropy Methods in Moessbauer Spectroscopy is presented. The most important advantage offered by the method is the correct data processing under circumstances of incomplete information. Disadvantage is the sophisticated algorithm and its application to the specific problems.

  5. The maximum entropy method of moments and Bayesian probability theory

    Science.gov (United States)

    Bretthorst, G. Larry

    2013-08-01

    The problem of density estimation occurs in many disciplines. For example, in MRI it is often necessary to classify the types of tissues in an image. To perform this classification one must first identify the characteristics of the tissues to be classified. These characteristics might be the intensity of a T1 weighted image and in MRI many other types of characteristic weightings (classifiers) may be generated. In a given tissue type there is no single intensity that characterizes the tissue, rather there is a distribution of intensities. Often this distributions can be characterized by a Gaussian, but just as often it is much more complicated. Either way, estimating the distribution of intensities is an inference problem. In the case of a Gaussian distribution, one must estimate the mean and standard deviation. However, in the Non-Gaussian case the shape of the density function itself must be inferred. Three common techniques for estimating density functions are binned histograms [1, 2], kernel density estimation [3, 4], and the maximum entropy method of moments [5, 6]. In the introduction, the maximum entropy method of moments will be reviewed. Some of its problems and conditions under which it fails will be discussed. Then in later sections, the functional form of the maximum entropy method of moments probability distribution will be incorporated into Bayesian probability theory. It will be shown that Bayesian probability theory solves all of the problems with the maximum entropy method of moments. One gets posterior probabilities for the Lagrange multipliers, and, finally, one can put error bars on the resulting estimated density function.

  6. Biomaterials for MEMS

    CERN Document Server

    Chiao, Mu

    2011-01-01

    This book serves as a guide for practicing engineers, researchers, and students interested in MEMS devices that use biomaterials and biomedical applications. It is also suitable for engineers and researchers interested in MEMS and its applications but who do not have the necessary background in biomaterials.Biomaterials for MEMS highlights important features and issues of biomaterials that have been used in MEMS and biomedical areas. Hence this book is an essential guide for MEMS engineers or researchers who are trained in engineering institutes that do not provide the background or knowledge

  7. Design of Surface micromachined Compliant MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Joe Anthony [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The consideration of compliant mechanisms as Microelectromechanical Systems (MEMS) is the focus of this research endeavor. MEMS are micron to millimeter devices that combine electrical, mechanical, and information processing capabilities on the same device. These MEMS need some mechanical motion or parts that move relative to each other. This relative motion, using multiple parts, is not desired because of the assembly requirement and the friction introduced. Compliant devices limits or eliminates friction and the need for multi-component assembly. Compliant devices improve designs by creating single piece mechanisms. The purpose of this research is to validate surface micromachining as a viable fabrication process for compliant MEMS designs. Specifically, this research has sought to fabricate a micro-compliant gripper and a micro-compliant clamp to illustrate the process. While other researchers have created compliant MEMS, most have used comb-drive actuation methods and bulk micromachining processes. This research focuses on fully-compliant devices that use device flexibility for motion and actuation. Validation of these compliant MEMS is achieved by structural optimization of device design and functional performance testing. This research contributes to the ongoing research in MEMS by evaluating the potential of using surface micromachining as a process for fabricating compliant micro-mechanisms.

  8. Design of Surface Micromachined Compliant MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Joe Anthony [Iowa State Univ., Ames, IA (United States)

    2002-12-31

    The consideration of compliant mechanisms as Microelectromechanical Systems (MEMS) is the focus of this research endeavor. MEMS are micron to millimeter devices that combine electrical, mechanical, and information processing capabilities on the same device. These MEMS need some mechanical motion or parts that move relative to each other. This relative motion, using multiple parts, is not desired because of the assembly requirement and the friction introduced. Compliant devices limits or eliminates friction and the need for multi-component assembly. Compliant devices improve designs by creating single piece mechanisms. The purpose of this research is to validate surface micromachining as a viable fabrication process for compliant MEMS designs. Specifically, this research has sought to fabricate a micro-compliant gripper and a micro-compliant clamp to illustrate the process. While other researchers have created compliant MEMs, most have used comb-drive actuation methods and bulk micromachining processes. This research focused on fully-compliant devices that use device flexibility for motion and actuation. Validation of these compliant MEMS is achieved by structural optimization of device design and functional performance testing. This research contributes to the ongoing research in MEMS by evaluating the potential of using surface micromachining as a process for fabricating compliant micro-mechanisms.

  9. New Fault Recognition Method for Rotary Machinery Based on Information Entropy and a Probabilistic Neural Network.

    Science.gov (United States)

    Jiang, Quansheng; Shen, Yehu; Li, Hua; Xu, Fengyu

    2018-01-24

    Feature recognition and fault diagnosis plays an important role in equipment safety and stable operation of rotating machinery. In order to cope with the complexity problem of the vibration signal of rotating machinery, a feature fusion model based on information entropy and probabilistic neural network is proposed in this paper. The new method first uses information entropy theory to extract three kinds of characteristics entropy in vibration signals, namely, singular spectrum entropy, power spectrum entropy, and approximate entropy. Then the feature fusion model is constructed to classify and diagnose the fault signals. The proposed approach can combine comprehensive information from different aspects and is more sensitive to the fault features. The experimental results on simulated fault signals verified better performances of our proposed approach. In real two-span rotor data, the fault detection accuracy of the new method is more than 10% higher compared with the methods using three kinds of information entropy separately. The new approach is proved to be an effective fault recognition method for rotating machinery.

  10. Symbolic phase transfer entropy method and its application

    Science.gov (United States)

    Zhang, Ningning; Lin, Aijing; Shang, Pengjian

    2017-10-01

    In this paper, we introduce symbolic phase transfer entropy (SPTE) to infer the direction and strength of information flow among systems. The advantages of the proposed method are investigated by simulations on synthetic signals and real-world data. We demonstrate that symbolic phase transfer entropy is a robust and efficient tool to infer the information flow between complex systems. Based on the study of the synthetic data, we find a significant advantage of SPTE is its reduced sensitivity to noise. In addition, SPTE requires less amount of data than symbolic transfer entropy(STE). We analyze the direction and strength of information flow between six stock markets during the period from 2006 to 2016. The results indicate that the information flow among stocks varies over different periods. We also find that the interaction network pattern among stocks undergoes hierarchial reorganization with transition from one period to another. It is shown that the clusters are mainly classified according to period, and then by region. The stocks during the same time period are shown to drop into the same cluster.

  11. Complexity Quantification for Overhead Transmission Line Emergency Repair Scheme via a Graph Entropy Method Improved with Petri Net and AHP Weighting Method

    Directory of Open Access Journals (Sweden)

    Jing Zhou

    2014-01-01

    Full Text Available According to the characteristics of emergency repair in overhead transmission line accidents, a complexity quantification method for emergency repair scheme is proposed based on the entropy method in software engineering, which is improved by using group AHP (analytical hierarchical process method and Petri net. Firstly, information structure chart model and process control flowchart model could be built by Petri net. Then impact factors on complexity of emergency repair scheme could be quantified into corresponding entropy values, respectively. Finally, by using group AHP method, weight coefficient of each entropy value would be given before calculating the overall entropy value for the whole emergency repair scheme. By comparing group AHP weighting method with average weighting method, experiment results for the former showed a stronger correlation between quantified entropy values of complexity and the actual consumed time in repair, which indicates that this new method is more valid.

  12. Carbon microelectromechanical systems (C-MEMS) based microsupercapacitors

    KAUST Repository

    Agrawal, Richa

    2015-05-18

    The rapid development in miniaturized electronic devices has led to an ever increasing demand for high-performance rechargeable micropower scources. Microsupercapacitors in particular have gained much attention in recent years owing to their ability to provide high pulse power while maintaining long cycle lives. Carbon microelectromechanical systems (C-MEMS) is a powerful approach to fabricate high aspect ratio carbon microelectrode arrays, which has been proved to hold great promise as a platform for energy storage. C-MEMS is a versatile technique to create carbon structures by pyrolyzing a patterned photoresist. Furthermore, different active materials can be loaded onto these microelectrode platforms for further enhancement of the electrochemical performance of the C-MEMS platform. In this article, different techniques and methods in order to enhance C-MEMS based various electrochemical capacitor systems have been discussed, including electrochemical activation of C-MEMS structures for miniaturized supercapacitor applications, integration of carbon nanostructures like carbon nanotubes onto C-MEMS structures and also integration of pseudocapacitive materials such as polypyrrole onto C-MEMS structures. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  13. Carbon microelectromechanical systems (C-MEMS) based microsupercapacitors

    KAUST Repository

    Agrawal, Richa; Beidaghi, Majid; Chen, Wei; Wang, Chunlei

    2015-01-01

    The rapid development in miniaturized electronic devices has led to an ever increasing demand for high-performance rechargeable micropower scources. Microsupercapacitors in particular have gained much attention in recent years owing to their ability to provide high pulse power while maintaining long cycle lives. Carbon microelectromechanical systems (C-MEMS) is a powerful approach to fabricate high aspect ratio carbon microelectrode arrays, which has been proved to hold great promise as a platform for energy storage. C-MEMS is a versatile technique to create carbon structures by pyrolyzing a patterned photoresist. Furthermore, different active materials can be loaded onto these microelectrode platforms for further enhancement of the electrochemical performance of the C-MEMS platform. In this article, different techniques and methods in order to enhance C-MEMS based various electrochemical capacitor systems have been discussed, including electrochemical activation of C-MEMS structures for miniaturized supercapacitor applications, integration of carbon nanostructures like carbon nanotubes onto C-MEMS structures and also integration of pseudocapacitive materials such as polypyrrole onto C-MEMS structures. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  14. A simple method for estimating the entropy of neural activity

    International Nuclear Information System (INIS)

    Berry II, Michael J; Tkačik, Gašper; Dubuis, Julien; Marre, Olivier; Da Silveira, Rava Azeredo

    2013-01-01

    The number of possible activity patterns in a population of neurons grows exponentially with the size of the population. Typical experiments explore only a tiny fraction of the large space of possible activity patterns in the case of populations with more than 10 or 20 neurons. It is thus impossible, in this undersampled regime, to estimate the probabilities with which most of the activity patterns occur. As a result, the corresponding entropy—which is a measure of the computational power of the neural population—cannot be estimated directly. We propose a simple scheme for estimating the entropy in the undersampled regime, which bounds its value from both below and above. The lower bound is the usual ‘naive’ entropy of the experimental frequencies. The upper bound results from a hybrid approximation of the entropy which makes use of the naive estimate, a maximum entropy fit, and a coverage adjustment. We apply our simple scheme to artificial data, in order to check their accuracy; we also compare its performance to those of several previously defined entropy estimators. We then apply it to actual measurements of neural activity in populations with up to 100 cells. Finally, we discuss the similarities and differences between the proposed simple estimation scheme and various earlier methods. (paper)

  15. RELAP-7 Numerical Stabilization: Entropy Viscosity Method

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Berry; M. O. Delchini; J. Ragusa

    2014-06-01

    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.

  16. Wafer-Level Packaging Method for RF MEMS Applications Using Pre-Patterned BCB Polymer

    Directory of Open Access Journals (Sweden)

    Zhuhao Gong

    2018-02-01

    Full Text Available A radio-frequency micro-electro-mechanical system (RF MEMS wafer-level packaging (WLP method using pre-patterned benzo-cyclo-butene (BCB polymers with a high-resistivity silicon cap is proposed to achieve high bonding quality and excellent RF performance. In this process, the BCB polymer was pre-defined to form the sealing ring and bonding layer by the spin-coating and patterning of photosensitive BCB before the cavity formation. During anisotropic wet etching of the silicon wafer to generate the housing cavity, the BCB sealing ring was protected by a sputtered Cr/Au (chromium/gold layer. The average measured thickness of the BCB layer was 5.9 μm. In contrast to the conventional methods of spin-coating BCB after fabricating cavities, the pre-patterned BCB method presented BCB bonding layers with better quality on severe topography surfaces in terms of increased uniformity of thickness and better surface flatness. The observation of the bonded layer showed that no void or gap formed on the protruding coplanar waveguide (CPW lines. A shear strength test was experimentally implemented as a function of the BCB widths in the range of 100–400 μm. The average shear strength of the packaged device was higher than 21.58 MPa. A RF MEMS switch was successfully packaged using this process with a negligible impact on the microwave characteristics and a significant improvement in the lifetime from below 10 million to over 1 billion. The measured insertion loss of the packaged RF MEMS switch was 0.779 dB and the insertion loss deterioration caused by the package structure was less than 0.2 dB at 30 GHz.

  17. Minimum entropy density method for the time series analysis

    Science.gov (United States)

    Lee, Jeong Won; Park, Joongwoo Brian; Jo, Hang-Hyun; Yang, Jae-Suk; Moon, Hie-Tae

    2009-01-01

    The entropy density is an intuitive and powerful concept to study the complicated nonlinear processes derived from physical systems. We develop the minimum entropy density method (MEDM) to detect the structure scale of a given time series, which is defined as the scale in which the uncertainty is minimized, hence the pattern is revealed most. The MEDM is applied to the financial time series of Standard and Poor’s 500 index from February 1983 to April 2006. Then the temporal behavior of structure scale is obtained and analyzed in relation to the information delivery time and efficient market hypothesis.

  18. Method of forming a package for MEMS-based fuel cell

    Science.gov (United States)

    Morse, Jeffrey D; Jankowski, Alan F

    2013-05-21

    A MEMS-based fuel cell package and method thereof is disclosed. The fuel cell package comprises seven layers: (1) a sub-package fuel reservoir interface layer, (2) an anode manifold support layer, (3) a fuel/anode manifold and resistive heater layer, (4) a Thick Film Microporous Flow Host Structure layer containing a fuel cell, (5) an air manifold layer, (6) a cathode manifold support structure layer, and (7) a cap. Fuel cell packages with more than one fuel cell are formed by positioning stacks of these layers in series and/or parallel. The fuel cell package materials such as a molded plastic or a ceramic green tape material can be patterned, aligned and stacked to form three dimensional microfluidic channels that provide electrical feedthroughs from various layers which are bonded together and mechanically support a MEMS-based miniature fuel cell. The package incorporates resistive heating elements to control the temperature of the fuel cell stack. The package is fired to form a bond between the layers and one or more microporous flow host structures containing fuel cells are inserted within the Thick Film Microporous Flow Host Structure layer of the package.

  19. Applications of the Maximum Entropy Method in superspace

    Czech Academy of Sciences Publication Activity Database

    van Smaalen, S.; Palatinus, Lukáš

    2004-01-01

    Roč. 305, - (2004), s. 57-62 ISSN 0015-0193 Grant - others:DFG and FCI(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : Maximum Entropy Method * modulated structures * charge density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.517, year: 2004

  20. The entropy dissipation method for spatially inhomogeneous reaction-diffusion-type systems

    KAUST Repository

    Di Francesco, M.

    2008-12-08

    We study the long-time asymptotics of reaction-diffusion-type systems that feature a monotone decaying entropy (Lyapunov, free energy) functional. We consider both bounded domains and confining potentials on the whole space for arbitrary space dimensions. Our aim is to derive quantitative expressions for (or estimates of) the rates of convergence towards an (entropy minimizing) equilibrium state in terms of the constants of diffusion and reaction and with respect to conserved quantities. Our method, the so-called entropy approach, seeks to quantify convergence to equilibrium by using functional inequalities, which relate quantitatively the entropy and its dissipation in time. The entropy approach is well suited to nonlinear problems and known to be quite robust with respect to model variations. It has already been widely applied to scalar diffusion-convection equations, and the main goal of this paper is to study its generalization to systems of partial differential equations that contain diffusion and reaction terms and admit fewer conservation laws than the size of the system. In particular, we successfully apply the entropy approach to general linear systems and to a nonlinear example of a reaction-diffusion-convection system arising in solid-state physics as a paradigm for general nonlinear systems. © 2008 The Royal Society.

  1. A Widely-Accessible Distributed MEMS Processing Environment. The MEMS Exchange Program

    Science.gov (United States)

    2012-10-29

    all of these patterns in advance, we made a new cost model, called the Python Code cost model, which utilizes the power of a high level programming ...document entitled “The Beginners Guide to MEMS Processing” on the MEMSNet and MEMS Exchange The MEMS Exchange Program Final Technical Report October 29...from the Government is absolutely necessary. As said The MEMS Exchange Program Final Technical Report October 29, 2012 Page 57 of 58 before

  2. Unification of field theory and maximum entropy methods for learning probability densities

    Science.gov (United States)

    Kinney, Justin B.

    2015-09-01

    The need to estimate smooth probability distributions (a.k.a. probability densities) from finite sampled data is ubiquitous in science. Many approaches to this problem have been described, but none is yet regarded as providing a definitive solution. Maximum entropy estimation and Bayesian field theory are two such approaches. Both have origins in statistical physics, but the relationship between them has remained unclear. Here I unify these two methods by showing that every maximum entropy density estimate can be recovered in the infinite smoothness limit of an appropriate Bayesian field theory. I also show that Bayesian field theory estimation can be performed without imposing any boundary conditions on candidate densities, and that the infinite smoothness limit of these theories recovers the most common types of maximum entropy estimates. Bayesian field theory thus provides a natural test of the maximum entropy null hypothesis and, furthermore, returns an alternative (lower entropy) density estimate when the maximum entropy hypothesis is falsified. The computations necessary for this approach can be performed rapidly for one-dimensional data, and software for doing this is provided.

  3. Unification of field theory and maximum entropy methods for learning probability densities.

    Science.gov (United States)

    Kinney, Justin B

    2015-09-01

    The need to estimate smooth probability distributions (a.k.a. probability densities) from finite sampled data is ubiquitous in science. Many approaches to this problem have been described, but none is yet regarded as providing a definitive solution. Maximum entropy estimation and Bayesian field theory are two such approaches. Both have origins in statistical physics, but the relationship between them has remained unclear. Here I unify these two methods by showing that every maximum entropy density estimate can be recovered in the infinite smoothness limit of an appropriate Bayesian field theory. I also show that Bayesian field theory estimation can be performed without imposing any boundary conditions on candidate densities, and that the infinite smoothness limit of these theories recovers the most common types of maximum entropy estimates. Bayesian field theory thus provides a natural test of the maximum entropy null hypothesis and, furthermore, returns an alternative (lower entropy) density estimate when the maximum entropy hypothesis is falsified. The computations necessary for this approach can be performed rapidly for one-dimensional data, and software for doing this is provided.

  4. Entropy Viscosity Method for High-Order Approximations of Conservation Laws

    KAUST Repository

    Guermond, J. L.

    2010-09-17

    A stabilization technique for conservation laws is presented. It introduces in the governing equations a nonlinear dissipation function of the residual of the associated entropy equation and bounded from above by a first order viscous term. Different two-dimensional test cases are simulated - a 2D Burgers problem, the "KPP rotating wave" and the Euler system - using high order methods: spectral elements or Fourier expansions. Details on the tuning of the parameters controlling the entropy viscosity are given. © 2011 Springer.

  5. Entropy Viscosity Method for High-Order Approximations of Conservation Laws

    KAUST Repository

    Guermond, J. L.; Pasquetti, R.

    2010-01-01

    A stabilization technique for conservation laws is presented. It introduces in the governing equations a nonlinear dissipation function of the residual of the associated entropy equation and bounded from above by a first order viscous term. Different two-dimensional test cases are simulated - a 2D Burgers problem, the "KPP rotating wave" and the Euler system - using high order methods: spectral elements or Fourier expansions. Details on the tuning of the parameters controlling the entropy viscosity are given. © 2011 Springer.

  6. Corrected entropy of Friedmann-Robertson-Walker universe in tunneling method

    International Nuclear Information System (INIS)

    Zhu, Tao; Ren, Ji-Rong; Li, Ming-Fan

    2009-01-01

    In this paper, we study the thermodynamic quantities of Friedmann-Robertson-Walker (FRW) universe by using the tunneling formalism beyond semiclassical approximation developed by Banerjee and Majhi [25]. For this we first calculate the corrected Hawking-like temperature on apparent horizon by considering both scalar particle and fermion tunneling. With this corrected Hawking-like temperature, the explicit expressions of the corrected entropy of apparent horizon for various gravity theories including Einstein gravity, Gauss-Bonnet gravity, Lovelock gravity, f(R) gravity and scalar-tensor gravity, are computed. Our results show that the corrected entropy formula for different gravity theories can be written into a general expression (4.39) of a same form. It is also shown that this expression is also valid for black holes. This might imply that the expression for the corrected entropy derived from tunneling method is independent of gravity theory, spacetime and dimension of the spacetime. Moreover, it is concluded that the basic thermodynamical property that the corrected entropy on apparent horizon is a state function is satisfied by the FRW universe

  7. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

    Science.gov (United States)

    Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

    2016-05-31

    The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  8. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

    Directory of Open Access Journals (Sweden)

    Chong Shen

    2016-05-01

    Full Text Available The different noise components in a dual-mass micro-electromechanical system (MEMS gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN, electronic-thermal noise (ETN, flicker noise (FN and Coriolis signal in-phase noise (IPN. The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD and time-frequency peak filtering (TFPF. There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  9. Attitude Determination Method by Fusing Single Antenna GPS and Low Cost MEMS Sensors Using Intelligent Kalman Filter Algorithm

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2017-01-01

    Full Text Available For meeting the demands of cost and size for micronavigation system, a combined attitude determination approach with sensor fusion algorithm and intelligent Kalman filter (IKF on low cost Micro-Electro-Mechanical System (MEMS gyroscope, accelerometer, and magnetometer and single antenna Global Positioning System (GPS is proposed. The effective calibration method is performed to compensate the effect of errors in low cost MEMS Inertial Measurement Unit (IMU. The different control strategies fusing the MEMS multisensors are designed. The yaw angle fusing gyroscope, accelerometer, and magnetometer algorithm is estimated accurately under GPS failure and unavailable sideslip situations. For resolving robust control and characters of the uncertain noise statistics influence, the high gain scale of IKF is adjusted by fuzzy controller in the transition process and steady state to achieve faster convergence and accurate estimation. The experiments comparing different MEMS sensors and fusion algorithms are implemented to verify the validity of the proposed approach.

  10. Logarithmic black hole entropy corrections and holographic Renyi entropy

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, Subhash [The Institute of Mathematical Sciences, Chennai (India); KU Leuven - KULAK, Department of Physics, Kortrijk (Belgium)

    2018-01-15

    The entanglement and Renyi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Renyi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order G{sub D}{sup 0}. The entropic c-function and the inequalities of the Renyi entropy are also satisfied even with the correction terms. (orig.)

  11. Logarithmic black hole entropy corrections and holographic Renyi entropy

    International Nuclear Information System (INIS)

    Mahapatra, Subhash

    2018-01-01

    The entanglement and Renyi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Renyi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order G D 0 . The entropic c-function and the inequalities of the Renyi entropy are also satisfied even with the correction terms. (orig.)

  12. Conditional maximum-entropy method for selecting prior distributions in Bayesian statistics

    Science.gov (United States)

    Abe, Sumiyoshi

    2014-11-01

    The conditional maximum-entropy method (abbreviated here as C-MaxEnt) is formulated for selecting prior probability distributions in Bayesian statistics for parameter estimation. This method is inspired by a statistical-mechanical approach to systems governed by dynamics with largely separated time scales and is based on three key concepts: conjugate pairs of variables, dimensionless integration measures with coarse-graining factors and partial maximization of the joint entropy. The method enables one to calculate a prior purely from a likelihood in a simple way. It is shown, in particular, how it not only yields Jeffreys's rules but also reveals new structures hidden behind them.

  13. A novel evaluation of heat-electricity cost allocation in cogenerations based on entropy change method

    International Nuclear Information System (INIS)

    Ye, Xuemin; Li, Chunxi

    2013-01-01

    As one of the most significant measures to improve energy utilization efficiency and save energy, cogeneration or combined heat and power (CHP) has been widely applied and promoted with positive motivations in many countries. A rational cost allocation model should indicate the performance of cogenerations and balance the benefits between electricity generation and heat production. Based on the second law of thermodynamics, the present paper proposes an entropy change method for cost allocation by choosing exhaust steam entropy as a datum point, and the new model works in conjunction with entropy change and irreversibility during energy conversion processes. The allocation ratios of heat cost with the present and existing methods are compared for different types of cogenerations. Results show that the allocation ratios with the entropy change method are more rational and the cost allocation model can make up some limitations involved in other approaches. The future energy policies and innovational directions for cogenerations and heat consumers should be developed. - Highlights: • A rational model of cogeneration cost allocation is established. • Entropy change method integrates the relation of entropy change and exergy losses. • The unity of measuring energy quality and quantity is materialized. • The benefits between electricity generation and heat production are balanced

  14. Robust optimum design with maximum entropy method; Saidai entropy ho mochiita robust sei saitekika sekkeiho

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, K; Egashira, Y; Watanabe, G [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    Vehicle and unit performance change according to not only external causes represented by the environment such as temperature or weather, but also internal causes which are dispersion of component characteristics and manufacturing processes or aged deteriorations. We developed the design method to estimate thus performance distributions with maximum entropy method and to calculate specifications with high performance robustness using Fuzzy theory. This paper describes the details of these methods and examples applied to power window system. 3 refs., 7 figs., 4 tabs.

  15. Entanglement entropy and differential entropy for massive flavors

    International Nuclear Information System (INIS)

    Jones, Peter A.R.; Taylor, Marika

    2015-01-01

    In this paper we compute the holographic entanglement entropy for massive flavors in the D3-D7 system, for arbitrary mass and various entangling region geometries. We show that the universal terms in the entanglement entropy exactly match those computed in the dual theory using conformal perturbation theory. We derive holographically the universal terms in the entanglement entropy for a CFT perturbed by a relevant operator, up to second order in the coupling; our results are valid for any entangling region geometry. We present a new method for computing the entanglement entropy of any top-down brane probe system using Kaluza-Klein holography and illustrate our results with massive flavors at finite density. Finally we discuss the differential entropy for brane probe systems, emphasising that the differential entropy captures only the effective lower-dimensional Einstein metric rather than the ten-dimensional geometry.

  16. Gamma-ray spectra deconvolution by maximum-entropy methods

    International Nuclear Information System (INIS)

    Los Arcos, J.M.

    1996-01-01

    A maximum-entropy method which includes the response of detectors and the statistical fluctuations of spectra is described and applied to the deconvolution of γ-ray spectra. Resolution enhancement of 25% can be reached for experimental peaks and up to 50% for simulated ones, while the intensities are conserved within 1-2%. (orig.)

  17. Investigating ESD sensitivity in electrostatic SiGe MEMS

    International Nuclear Information System (INIS)

    Sangameswaran, Sandeep; De Coster, Jeroen; Linten, Dimitri; Scholz, Mirko; Thijs, Steven; Groeseneken, Guido; De Wolf, Ingrid

    2010-01-01

    The sensitivity of electrostatically actuated SiGe microelectromechanical systems to electrostatic discharge events has been investigated in this paper. Torsional micromirrors and RF microelectromechanical systems (MEMS) actuators have been used as two case studies to perform this study. On-wafer electrostatic discharge (ESD) measurement methods, such as the human body model (HBM) and machine model (MM), are discussed. The impact of HBM ESD zap tests on the functionality and behavior of MEMS is explained and the ESD failure levels of MEMS have been verified by failure analysis. It is demonstrated that electrostatic MEMS devices have a high sensitivity to ESD and that it is essential to protect them.

  18. Logarithmic black hole entropy corrections and holographic Rényi entropy

    Science.gov (United States)

    Mahapatra, Subhash

    2018-01-01

    The entanglement and Rényi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Rényi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order GD^0. The entropic c-function and the inequalities of the Rényi entropy are also satisfied even with the correction terms.

  19. Entropy resistance minimization: An alternative method for heat exchanger analyses

    International Nuclear Information System (INIS)

    Cheng, XueTao

    2013-01-01

    In this paper, the concept of entropy resistance is proposed based on the entropy generation analyses of heat transfer processes. It is shown that smaller entropy resistance leads to larger heat transfer rate with fixed thermodynamic force difference and smaller thermodynamic force difference with fixed heat transfer rate, respectively. For the discussed two-stream heat exchangers in which the heat transfer rates are not given and the three-stream heat exchanger with prescribed heat capacity flow rates and inlet temperatures of the streams, smaller entropy resistance leads to larger heat transfer rate. For the two-stream heat exchangers with fixed heat transfer rate, smaller entropy resistance leads to larger effectiveness. Furthermore, it is shown that smaller values of the concepts of entropy generation numbers and modified entropy generation number do not always correspond to better performance of the discussed heat exchangers. - Highlights: • The concept of entropy resistance is defined for heat exchangers. • The concepts based on entropy generation are used to analyze heat exchangers. • Smaller entropy resistance leads to better performance of heat exchangers. • The applicability of entropy generation minimization is conditional

  20. MEMS mass-spring-damper systems using an out-of-plane suspension scheme

    KAUST Repository

    Abdel Aziz, Ahmed Kamal Said; Sharaf, Abdel Hameed; Serry, Mohamed Yousef; Sedky, Sherif Salah

    2014-01-01

    MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

  1. MEMS mass-spring-damper systems using an out-of-plane suspension scheme

    KAUST Repository

    Abdel Aziz, Ahmed Kamal Said

    2014-02-04

    MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

  2. Power spectrum of the geomagnetic field by the maximum entropy method

    International Nuclear Information System (INIS)

    Kantor, I.J.; Trivedi, N.B.

    1980-01-01

    Monthly mean values of Vassouras (state of Rio de Janeiro) geomagnetic field are analyzed us the maximum entropy method. The method is described and compared with other methods of spectral analysis, and its advantages and disadvantages are presented. (Author) [pt

  3. MEMS for Tunable Photonic Metamaterial Applications

    Science.gov (United States)

    Stark, Thomas

    Photonic metamaterials are materials whose optical properties are derived from artificially-structured sub-wavelength unit cells, rather than from the bulk properties of the constituent materials. Examples of metamaterials include plasmonic materials, negative index materials, and electromagnetic cloaks. While advances in simulation tools and nanofabrication methods have allowed this field to grow over the past several decades, many challenges still exist. This thesis addresses two of these challenges: fabrication of photonic metamaterials with tunable responses and high-throughput nanofabrication methods for these materials. The design, fabrication, and optical characterization of a microelectromechanical systems (MEMS) tunable plasmonic spectrometer are presented. An array of holes in a gold film, with plasmon resonance in the mid-infrared, is suspended above a gold reflector, forming a Fabry-Perot interferometer of tunable length. The spectra exhibit the convolution of extraordinary optical transmission through the holes and Fabry-Perot resonances. Using MEMS, the interferometer length is modulated from 1.7 mum to 21.67 mum , thereby tuning the free spectral range from about 2900 wavenumbers to 230.7 wavenumbers and shifting the reflection minima and maxima across the infrared. Due to its broad spectral tunability in the fingerprint region of the mid-infrared, this device shows promise as a tunable biological sensing device. To address the issue of high-throughput, high-resolution fabrication of optical metamaterials, atomic calligraphy, a MEMS-based dynamic stencil lithography technique for resist-free fabrication of photonic metamaterials on unconventional substrates, has been developed. The MEMS consists of a moveable stencil, which can be actuated with nanometer precision using electrostatic comb drive actuators. A fabrication method and flip chip method have been developed, enabling evaporation of metals through the device handle for fabrication on an

  4. Maximum entropy and Bayesian methods

    International Nuclear Information System (INIS)

    Smith, C.R.; Erickson, G.J.; Neudorfer, P.O.

    1992-01-01

    Bayesian probability theory and Maximum Entropy methods are at the core of a new view of scientific inference. These 'new' ideas, along with the revolution in computational methods afforded by modern computers allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics. The title workshops have been the focus of a group of researchers from many different fields, and this diversity is evident in this book. There are tutorial and theoretical papers, and applications in a very wide variety of fields. Almost any instance of dealing with incomplete and noisy data can be usefully treated by these methods, and many areas of theoretical research are being enhanced by the thoughtful application of Bayes' theorem. Contributions contained in this volume present a state-of-the-art overview that will be influential and useful for many years to come

  5. EDITORIAL: International MEMS Conference 2006

    Science.gov (United States)

    Tay, Francis E. H.; Jianmin, Miao; Iliescu, Ciprian

    2006-04-01

    The International MEMS conference (iMEMS2006) organized by the Institute of Bioengineering and Nanotechnology and Nanyang Technological University aims to provide a platform for academicians, professionals and industrialists in various related fields from all over the world to share and learn from each other. Of great interest is the incorporation of the theme of life sciences application using MEMS. It is the desire of this conference to initiate collaboration and form network of cooperation. This has continued to be the objective of iMEMS since its inception in 1997. The technological advance of MEMS over the past few decades has been truly exciting in terms of development and applications. In order to participate in this rapid development, a conference involving delegates from within the MEMS community and outside the community is very meaningful and timely. With the receipt of over 200 articles, delegates related to MEMS field from all over the world will share their perspectives on topics such as MEMS/MST Design, MEMS Teaching and Education, MEMS/MST Packaging, MEMS/MST Fabrication, Microsystems Applications, System Integration, Wearable Devices, MEMSWear and BioMEMS. Invited speakers and delegates from outside the field have also been involved to provide challenges, especially in the life sciences field, for the MEMS community to potentially address. The proceedings of the conference will be published as an issue in the online Journal of Physics: Conference Series and this can reach a wider audience and will facilitate the reference and citation of the work presented in the conference. We wish to express our deep gratitude to the International Scientific Committee members and the organizing committee members for contributing to the success of this conference. We would like to thank all the delegates, speakers and sponsors from all over the world for presenting and sharing their perspectives on topics related to MEMS and the challenges that MEMS can

  6. A numerically research on energy loss evaluation in a centrifugal pump system based on local entropy production method

    Directory of Open Access Journals (Sweden)

    Hou Hucan

    2017-01-01

    Full Text Available Inspired by wide application of the second law of thermodynamics to flow and heat transfer devices, local entropy production analysis method was creatively introduced into energy assessment system of centrifugal water pump. Based on Reynolds stress turbulent model and energy equation model, the steady numerical simulation of the whole flow passage of one IS centrifugal pump was carried out. The local entropy production terms were calculated by user defined functions, mainly including wall entropy production, turbulent entropy production, and viscous entropy production. The numerical results indicated that the irreversible energy loss calculated by the local entropy production method agreed well with that calculated by the traditional method but with some deviations which were probably caused by high rotatability and high curvature of impeller and volute. The wall entropy production and turbulent entropy production took up large part of the whole entropy production about 48.61% and 47.91%, respectively, which indicated that wall friction and turbulent fluctuation were the major factors in affecting irreversible energy loss. Meanwhile, the entropy production rate distribution was discussed and compared with turbulent kinetic energy dissipation rate distribution, it showed that turbulent entropy production rate increased sharply at the near wall regions and both distributed more uniformly. The blade region in leading edge near suction side, trailing edge and volute tongue were the main regions to generate irreversible exergy loss. This research broadens a completely new view in evaluating energy loss and further optimizes pump using entropy production minimization.

  7. Advanced Mechatronics and MEMS Devices

    CERN Document Server

    2013-01-01

    Advanced Mechatronics and MEMS Devicesdescribes state-of-the-art MEMS devices and introduces the latest technology in electrical and mechanical microsystems. The evolution of design in microfabrication, as well as emerging issues in nanomaterials, micromachining, micromanufacturing and microassembly are all discussed at length in this volume. Advanced Mechatronics also provides a reader with knowledge of MEMS sensors array, MEMS multidimensional accelerometer, artificial skin with imbedded tactile components, as well as other topics in MEMS sensors and transducers. The book also presents a number of topics in advanced robotics and an abundance of applications of MEMS in robotics, like reconfigurable modular snake robots, magnetic MEMS robots for drug delivery and flying robots with adjustable wings, to name a few. This book also: Covers the fundamentals of advanced mechatronics and MEMS devices while also presenting new state-of-the-art methodology and technology used in the application of these devices Prese...

  8. An Entropy Stable h/p Non-Conforming Discontinuous Galerkin Method with the Summation-by-Parts Property

    KAUST Repository

    Friedrich, Lucas

    2017-12-29

    This work presents an entropy stable discontinuous Galerkin (DG) spectral element approximation for systems of non-linear conservation laws with general geometric (h) and polynomial order (p) non-conforming rectangular meshes. The crux of the proofs presented is that the nodal DG method is constructed with the collocated Legendre-Gauss-Lobatto nodes. This choice ensures that the derivative/mass matrix pair is a summation-by-parts (SBP) operator such that entropy stability proofs from the continuous analysis are discretely mimicked. Special attention is given to the coupling between nonconforming elements as we demonstrate that the standard mortar approach for DG methods does not guarantee entropy stability for non-linear problems, which can lead to instabilities. As such, we describe a precise procedure and modify the mortar method to guarantee entropy stability for general non-linear hyperbolic systems on h/p non-conforming meshes. We verify the high-order accuracy and the entropy conservation/stability of fully non-conforming approximation with numerical examples.

  9. A Dynamic and Adaptive Selection Radar Tracking Method Based on Information Entropy

    Directory of Open Access Journals (Sweden)

    Ge Jianjun

    2017-12-01

    Full Text Available Nowadays, the battlefield environment has become much more complex and variable. This paper presents a quantitative method and lower bound for the amount of target information acquired from multiple radar observations to adaptively and dynamically organize the detection of battlefield resources based on the principle of information entropy. Furthermore, for minimizing the given information entropy’s lower bound for target measurement at every moment, a method to dynamically and adaptively select radars with a high amount of information for target tracking is proposed. The simulation results indicate that the proposed method has higher tracking accuracy than that of tracking without adaptive radar selection based on entropy.

  10. A MEMS-based, wireless, biometric-like security system

    Science.gov (United States)

    Cross, Joshua D.; Schneiter, John L.; Leiby, Grant A.; McCarter, Steven; Smith, Jeremiah; Budka, Thomas P.

    2010-04-01

    We present a system for secure identification applications that is based upon biometric-like MEMS chips. The MEMS chips have unique frequency signatures resulting from fabrication process variations. The MEMS chips possess something analogous to a "voiceprint". The chips are vacuum encapsulated, rugged, and suitable for low-cost, highvolume mass production. Furthermore, the fabrication process is fully integrated with standard CMOS fabrication methods. One is able to operate the MEMS-based identification system similarly to a conventional RFID system: the reader (essentially a custom network analyzer) detects the power reflected across a frequency spectrum from a MEMS chip in its vicinity. We demonstrate prototype "tags" - MEMS chips placed on a credit card-like substrate - to show how the system could be used in standard identification or authentication applications. We have integrated power scavenging to provide DC bias for the MEMS chips through the use of a 915 MHz source in the reader and a RF-DC conversion circuit on the tag. The system enables a high level of protection against typical RFID hacking attacks. There is no need for signal encryption, so back-end infrastructure is minimal. We believe this system would make a viable low-cost, high-security system for a variety of identification and authentication applications.

  11. Information Entropy Measures for Stand Structural Diversity:Joint Entropy

    Institute of Scientific and Technical Information of China (English)

    Lei Xiangdong; Lu Yuanchang

    2004-01-01

    Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) has been the most widely used measure of species diversity. It is generally thought that tree size diversity could serve as a good proxy for height diversity. However, tree size diversity and height diversity for stand structure is not completely consistent. Stand diameter cannot reflect height information completely. Either tree size diversity or height diversity is one-dimensional information entropy measure. This paper discussed the method of multiple-dimensional information entropy measure with the concept of joint entropy. It is suggested that joint entropy is a good measure for describing overall stand structural diversity.

  12. Fault Diagnosis Method Based on Information Entropy and Relative Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Xiaoming Xu

    2017-01-01

    Full Text Available In traditional principle component analysis (PCA, because of the neglect of the dimensions influence between different variables in the system, the selected principal components (PCs often fail to be representative. While the relative transformation PCA is able to solve the above problem, it is not easy to calculate the weight for each characteristic variable. In order to solve it, this paper proposes a kind of fault diagnosis method based on information entropy and Relative Principle Component Analysis. Firstly, the algorithm calculates the information entropy for each characteristic variable in the original dataset based on the information gain algorithm. Secondly, it standardizes every variable’s dimension in the dataset. And, then, according to the information entropy, it allocates the weight for each standardized characteristic variable. Finally, it utilizes the relative-principal-components model established for fault diagnosis. Furthermore, the simulation experiments based on Tennessee Eastman process and Wine datasets demonstrate the feasibility and effectiveness of the new method.

  13. The improvement of Clausius entropy and its application in entropy analysis

    Institute of Scientific and Technical Information of China (English)

    WU Jing; GUO ZengYuan

    2008-01-01

    The defects of Cleusius entropy which Include s premise of reversible process and a process quantlty of heat in Its definition are discussed in this paper. Moreover, the heat temperature quotient under reversible conditions, i.e. (δQ/T)rev, is essentially a process quantity although it is numerically equal to the entropy change. The sum of internal energy temperature quotient and work temperature quotient is defined as the improved form of Clausius entropy and it can be further proved to be a state funcllon. Unlike Clausius entropy, the improved deflnltion consists of system properties wlthout premise just like other state functions, for example, pressure p and enthalpy h, etc. it is unnecessary to invent reversible paths when calculating entropy change for irreversible processes based on the improved form of entropy since it is independent of process. Furthermore, entropy balance equations for internally and externally irreversible processes are deduced respectively based on the concepts of thermal reservoir entropy transfer and system entropy transfer. Finally, some examples are presented to show that the improved deflnitlon of Clausius entropy provides a clear concept as well as a convenient method for en-tropy change calculation.

  14. Converting MEMS technology into profits

    Science.gov (United States)

    Bryzek, Janusz

    1998-08-01

    This paper discusses issues related to transitioning a company from the advanced technology development phase (with a particular focus on MEMS) to a profitable business, with emphasis on start-up companies. It includes several case studies from (primarily) NovaSensor MEMS development history. These case studies illustrate strategic problems with which advanced MEMS technology developers have to be concerned. Conclusions from these case studies could be used as checkpoints for future MEMS developers to increase probability of profitable operations. The objective for this paper is to share the author's experience from multiple MEMS start-ups to accelerate development of the MEMS market by focusing state- of-the-art technologists on marketing issues.

  15. Review of MEMS differential scanning calorimetry for biomolecular study

    Science.gov (United States)

    Yu, Shifeng; Wang, Shuyu; Lu, Ming; Zuo, Lei

    2017-12-01

    Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.

  16. The prior-derived F constraints in the maximum-entropy method

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; van Smaalen, S.

    2005-01-01

    Roč. 61, - (2005), s. 363-372 ISSN 0108-7673 Institutional research plan: CEZ:AV0Z10100521 Keywords : charge density * maximum-entropy method * sodium nitrite Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.791, year: 2005

  17. Variational method for the minimization of entropy generation in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Sjoerd; Kessels, W. M. M., E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2015-04-07

    In this work, a method is presented to extend traditional solar cell simulation tools to make it possible to calculate the most efficient design of practical solar cells. The method is based on the theory of nonequilibrium thermodynamics, which is used to derive an expression for the local entropy generation rate in the solar cell, making it possible to quantify all free energy losses on the same scale. The framework of non-equilibrium thermodynamics can therefore be combined with the calculus of variations and existing solar cell models to minimize the total entropy generation rate in the cell to find the most optimal design. The variational method is illustrated by applying it to a homojunction solar cell. The optimization results in a set of differential algebraic equations, which determine the optimal shape of the doping profile for given recombination and transport models.

  18. Entropy generation method to quantify thermal comfort

    Science.gov (United States)

    Boregowda, S. C.; Tiwari, S. N.; Chaturvedi, S. K.

    2001-01-01

    The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a function of entropy generation. In order to verify the entropy-based thermal comfort model, human thermal physiological responses due to changes in ambient conditions are simulated using a well established and validated human thermal model developed at the Institute of Environmental Research of Kansas State University (KSU). The finite element based KSU human thermal computer model is being utilized as a "Computational Environmental Chamber" to conduct series of simulations to examine the human thermal responses to different environmental conditions. The output from the simulation, which include human thermal responses and input data consisting of environmental conditions are fed into the thermal comfort model. Continuous monitoring of thermal comfort in comfortable and extreme environmental conditions is demonstrated. The Objective Thermal Comfort values obtained from the entropy-based model are validated against regression based Predicted Mean Vote (PMV) values. Using the corresponding air temperatures and vapor pressures that were used in the computer simulation in the regression equation generates the PMV values. The preliminary results indicate that the OTCI and PMV values correlate well under ideal conditions. However, an experimental study

  19. An entropy-based improved k-top scoring pairs (TSP) method for ...

    African Journals Online (AJOL)

    An entropy-based improved k-top scoring pairs (TSP) (Ik-TSP) method was presented in this study for the classification and prediction of human cancers based on gene-expression data. We compared Ik-TSP classifiers with 5 different machine learning methods and the k-TSP method based on 3 different feature selection ...

  20. The improvement of Clausius entropy and its application in entropy analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The defects of Clausius entropy which include a premise of reversible process and a process quantity of heat in its definition are discussed in this paper. Moreover, the heat temperature quotient under reversible conditions, i.e. (δQ/T)rev, is essentially a process quantity although it is numerically equal to the entropy change. The sum of internal energy temperature quotient and work temperature quotient is defined as the improved form of Clausius entropy and it can be further proved to be a state function. Unlike Clausius entropy, the improved definition consists of system properties without premise just like other state functions, for example, pressure p and enthalpy h, etc. It is unnecessary to invent reversible paths when calculating entropy change for irreversible processes based on the improved form of entropy since it is independent of process. Furthermore, entropy balance equations for internally and externally irreversible processes are deduced respectively based on the concepts of thermal reservoir entropy transfer and system entropy transfer. Finally, some examples are presented to show that the improved definition of Clausius entropy provides a clear concept as well as a convenient method for en- tropy change calculation.

  1. Unification of field theory and maximum entropy methods for learning probability densities

    OpenAIRE

    Kinney, Justin B.

    2014-01-01

    The need to estimate smooth probability distributions (a.k.a. probability densities) from finite sampled data is ubiquitous in science. Many approaches to this problem have been described, but none is yet regarded as providing a definitive solution. Maximum entropy estimation and Bayesian field theory are two such approaches. Both have origins in statistical physics, but the relationship between them has remained unclear. Here I unify these two methods by showing that every maximum entropy de...

  2. RNA Thermodynamic Structural Entropy.

    Directory of Open Access Journals (Sweden)

    Juan Antonio Garcia-Martin

    Full Text Available Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs. However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http

  3. RNA Thermodynamic Structural Entropy.

    Science.gov (United States)

    Garcia-Martin, Juan Antonio; Clote, Peter

    2015-01-01

    Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http

  4. Stability, Nonlinearity and Reliability of Electrostatically Actuated MEMS Devices

    Directory of Open Access Journals (Sweden)

    Di Chen

    2007-05-01

    Full Text Available Electrostatic micro-electro-mechanical system (MEMS is a special branch with a wide range of applications in sensing and actuating devices in MEMS. This paper provides a survey and analysis of the electrostatic force of importance in MEMS, its physical model, scaling effect, stability, nonlinearity and reliability in detail. It is necessary to understand the effects of electrostatic forces in MEMS and then many phenomena of practical importance, such as pull-in instability and the effects of effective stiffness, dielectric charging, stress gradient, temperature on the pull-in voltage, nonlinear dynamic effects and reliability due to electrostatic forces occurred in MEMS can be explained scientifically, and consequently the great potential of MEMS technology could be explored effectively and utilized optimally. A simplified parallel-plate capacitor model is proposed to investigate the resonance response, inherent nonlinearity, stiffness softened effect and coupled nonlinear effect of the typical electrostatically actuated MEMS devices. Many failure modes and mechanisms and various methods and techniques, including materials selection, reasonable design and extending the controllable travel range used to analyze and reduce the failures are discussed in the electrostatically actuated MEMS devices. Numerical simulations and discussions indicate that the effects of instability, nonlinear characteristics and reliability subjected to electrostatic forces cannot be ignored and are in need of further investigation.

  5. A Nuclear Microbattery for MEMS Devices

    International Nuclear Information System (INIS)

    Blanchard, James; Henderson, Douglass; Lal, Amit

    2002-01-01

    This project was designed to demonstrate the feasibility of producing on-board power for MEMS devices using radioisotopes. MEMS is a fast growing field, with hopes for producing a wide variety of revolutionary applications, including ''labs on a chip,'' micromachined scanning tunneling microscopes, microscopic detectors for biological agents, microsystems for DNA identification, etc. Currently, these applications are limited by the lack of an on-board power source. Research is ongoing to study approaches such as fuel cells, fossil fuels, and chemical batteries, but all these concepts have limitations. For long-lived, high energy density applications, on-board radioisotope power offers the best choice. We have succeeded in producing such devices using a variety of isotopes, incorporation methods, and device geometries. These experiments have demonstrated the feasibility of using radioisotope power and that there are a variety of options available for MEMS designers. As an example of an integrated, self-powered application, we have created an oscillating cantilever beam that is capable of consistent, periodic oscillations over very long time periods without the need for refueling. Ongoing work will demonstrate that this cantilever is capable of radio frequency transmission, allowing MEMS devices to communicate with one another wirelessly. Thus, this will be the first self-powered wireless transmitter available for use in MEMS devices, permitting such applications as sensors embedded in buildings for continuous monitoring of the building performance and integrity

  6. Application of the entropy generation minimization method to a solar heat exchanger: A pseudo-optimization design process based on the analysis of the local entropy generation maps

    International Nuclear Information System (INIS)

    Giangaspero, Giorgio; Sciubba, Enrico

    2013-01-01

    This paper presents an application of the entropy generation minimization method to the pseudo-optimization of the configuration of the heat exchange surfaces in a Solar Rooftile. An initial “standard” commercial configuration is gradually improved by introducing design changes aimed at the reduction of the thermodynamic losses due to heat transfer and fluid friction. Different geometries (pins, fins and others) are analysed with a commercial CFD (Computational Fluid Dynamics) code that also computes the local entropy generation rate. The design improvement process is carried out on the basis of a careful analysis of the local entropy generation maps and the rationale behind each step of the process is discussed in this perspective. The results are compared with other entropy generation minimization techniques available in the recent technical literature. It is found that the geometry with pin-fins has the best performance among the tested ones, and that the optimal pin array shape parameters (pitch and span) can be determined by a critical analysis of the integrated and local entropy maps and of the temperature contours. - Highlights: ► An entropy generation minimization method is applied to a solar heat exchanger. ► The approach is heuristic and leads to a pseudo-optimization process with CFD as main tool. ► The process is based on the evaluation of the local entropy generation maps. ► The geometry with pin-fins in general outperforms all other configurations. ► The entropy maps and temperature contours can be used to determine the optimal pin array design parameters

  7. Crane Safety Assessment Method Based on Entropy and Cumulative Prospect Theory

    Directory of Open Access Journals (Sweden)

    Aihua Li

    2017-01-01

    Full Text Available Assessing the safety status of cranes is an important problem. To overcome the inaccuracies and misjudgments in such assessments, this work describes a safety assessment method for cranes that combines entropy and cumulative prospect theory. Firstly, the proposed method transforms the set of evaluation indices into an evaluation vector. Secondly, a decision matrix is then constructed from the evaluation vectors and evaluation standards, and an entropy-based technique is applied to calculate the index weights. Thirdly, positive and negative prospect value matrices are established from reference points based on the positive and negative ideal solutions. Thus, this enables the crane safety grade to be determined according to the ranked comprehensive prospect values. Finally, the safety status of four general overhead traveling crane samples is evaluated to verify the rationality and feasibility of the proposed method. The results demonstrate that the method described in this paper can precisely and reasonably reflect the safety status of a crane.

  8. MEMS for automotive and aerospace applications

    CERN Document Server

    Kraft, Michael

    2013-01-01

    MEMS for automotive and aerospace applications reviews the use of Micro-Electro-Mechanical-Systems (MEMS) in developing solutions to the unique challenges presented by the automotive and aerospace industries.Part one explores MEMS for a variety of automotive applications. The role of MEMS in passenger safety and comfort, sensors for automotive vehicle stability control applications and automotive tire pressure monitoring systems are considered, along with pressure and flow sensors for engine management, and RF MEMS for automotive radar sensors. Part two then goes on to explore MEMS for

  9. Variational method for the minimization of entropy generation in solar cells

    NARCIS (Netherlands)

    Smit, S.; Kessels, W.M.M.

    2015-01-01

    In this work, a method is presented to extend traditional solar cell simulation tools to make it possible to calculate the most efficient design of practical solar cells. The method is based on the theory of nonequilibrium thermodynamics, which is used to derive an expression for the local entropy

  10. Enabling technology for MEMS and nanodevices

    CERN Document Server

    Baltes, Henry; Fedder, Gary K; Hierold, Christofer; Korvink, Jan G; Tabata, Osamu

    2013-01-01

    This softcover edition of the eponymous volume from the successful ""Advanced Micro & Nanosystems"" series covers all aspects of fabrication of MEMS under CMOS-compatible conditions from design to implementation.It examines the various routes and methods to combine electronics generated by the CMOS technology with novel micromechanical parts into one-chip solutions. Various approaches, fundamental and technological aspects as well as strategies leading to different types of functionalities and presented in detail.For the practicing engineer as well as MSc and PhD students on MEMS cours

  11. MEMS/MOEMS foundry services at INO

    Science.gov (United States)

    García-Blanco, Sonia; Ilias, Samir; Williamson, Fraser; Généreux, Francis; Le Noc, Loïc; Poirier, Michel; Proulx, Christian; Tremblay, Bruno; Provençal, Francis; Desroches, Yan; Caron, Jean-Sol; Larouche, Carl; Beaupré, Patrick; Fortin, Benoit; Topart, Patrice; Picard, Francis; Alain, Christine; Pope, Timothy; Jerominek, Hubert

    2010-06-01

    In the MEMS manufacturing world, the "fabless" model is getting increasing importance in recent years as a way for MEMS manufactures and startups to minimize equipment costs and initial capital investment. In order for this model to be successful, the fabless company needs to work closely with a MEMS foundry service provider. Due to the lack of standardization in MEMS processes, as opposed to CMOS microfabrication, the experience in MEMS development processes and the flexibility of the MEMS foundry are of vital importance. A multidisciplinary team together with a complete microfabrication toolset allows INO to offer unique MEMS foundry services to fabless companies looking for low to mid-volume production. Companies that benefit from their own microfabrication facilities can also be interested in INO's assistance in conducting their research and development work during periods where production runs keep their whole staff busy. Services include design, prototyping, fabrication, packaging, and testing of various MEMS and MOEMS devices on wafers fully compatible with CMOS integration. Wafer diameters ranging typically from 1 inch to 6 inches can be accepted while 8-inch wafers can be processed in some instances. Standard microfabrication techniques such as metal, dielectric, and semiconductor film deposition and etching as well as photolithographic pattern transfer are available. A stepper permits reduction of the critical dimension to around 0.4 μm. Metals deposited by vacuum deposition methods include Au, Ag, Al, Al alloys, Ti, Cr, Cu, Mo, MoCr, Ni, Pt, and V with thickness varying from 5 nm to 2 μm. Electroplating of several materials including Ni, Au and In is also available. In addition, INO has developed and built a gold black deposition facility to answer customer's needs for broadband microbolometric detectors. The gold black deposited presents specular reflectance of less than 10% in the wavelength range from 0.2 μm to 100 μm with thickness ranging from

  12. High-uniformity centimeter-wide Si etching method for MEMS devices with large opening elements

    Science.gov (United States)

    Okamoto, Yuki; Tohyama, Yukiya; Inagaki, Shunsuke; Takiguchi, Mikio; Ono, Tomoki; Lebrasseur, Eric; Mita, Yoshio

    2018-04-01

    We propose a compensated mesh pattern filling method to achieve highly uniform wafer depth etching (over hundreds of microns) with a large-area opening (over centimeter). The mesh opening diameter is gradually changed between the center and the edge of a large etching area. Using such a design, the etching depth distribution depending on sidewall distance (known as the local loading effect) inversely compensates for the over-centimeter-scale etching depth distribution, known as the global or within-die(chip)-scale loading effect. Only a single DRIE with test structure patterns provides a micro-electromechanical systems (MEMS) designer with the etched depth dependence on the mesh opening size as well as on the distance from the chip edge, and the designer only has to set the opening size so as to obtain a uniform etching depth over the entire chip. This method is useful when process optimization cannot be performed, such as in the cases of using standard conditions for a foundry service and of short turn-around-time prototyping. To demonstrate, a large MEMS mirror that needed over 1 cm2 of backside etching was successfully fabricated using as-is-provided DRIE conditions.

  13. [Identification of special quality eggs with NIR spectroscopy technology based on symbol entropy feature extraction method].

    Science.gov (United States)

    Zhao, Yong; Hong, Wen-Xue

    2011-11-01

    Fast, nondestructive and accurate identification of special quality eggs is an urgent problem. The present paper proposed a new feature extraction method based on symbol entropy to identify near infrared spectroscopy of special quality eggs. The authors selected normal eggs, free range eggs, selenium-enriched eggs and zinc-enriched eggs as research objects and measured the near-infrared diffuse reflectance spectra in the range of 12 000-4 000 cm(-1). Raw spectra were symbolically represented with aggregation approximation algorithm and symbolic entropy was extracted as feature vector. An error-correcting output codes multiclass support vector machine classifier was designed to identify the spectrum. Symbolic entropy feature is robust when parameter changed and the highest recognition rate reaches up to 100%. The results show that the identification method of special quality eggs using near-infrared is feasible and the symbol entropy can be used as a new feature extraction method of near-infrared spectra.

  14. Adaptive Subband Filtering Method for MEMS Accelerometer Noise Reduction

    Directory of Open Access Journals (Sweden)

    Piotr PIETRZAK

    2008-12-01

    Full Text Available Silicon microaccelerometers can be considered as an alternative to high-priced piezoelectric sensors. Unfortunately, relatively high noise floor of commercially available MEMS (Micro-Electro-Mechanical Systems sensors limits the possibility of their usage in condition monitoring systems of rotating machines. The solution of this problem is the method of signal filtering described in the paper. It is based on adaptive subband filtering employing Adaptive Line Enhancer. For filter weights adaptation, two novel algorithms have been developed. They are based on the NLMS algorithm. Both of them significantly simplify its software and hardware implementation and accelerate the adaptation process. The paper also presents the software (Matlab and hardware (FPGA implementation of the proposed noise filter. In addition, the results of the performed tests are reported. They confirm high efficiency of the solution.

  15. CMOS MEMS Fabrication Technologies and Devices

    Directory of Open Access Journals (Sweden)

    Hongwei Qu

    2016-01-01

    Full Text Available This paper reviews CMOS (complementary metal-oxide-semiconductor MEMS (micro-electro-mechanical systems fabrication technologies and enabled micro devices of various sensors and actuators. The technologies are classified based on the sequence of the fabrication of CMOS circuitry and MEMS elements, while SOI (silicon-on-insulator CMOS MEMS are introduced separately. Introduction of associated devices follows the description of the respective CMOS MEMS technologies. Due to the vast array of CMOS MEMS devices, this review focuses only on the most typical MEMS sensors and actuators including pressure sensors, inertial sensors, frequency reference devices and actuators utilizing different physics effects and the fabrication processes introduced. Moreover, the incorporation of MEMS and CMOS is limited to monolithic integration, meaning wafer-bonding-based stacking and other integration approaches, despite their advantages, are excluded from the discussion. Both competitive industrial products and state-of-the-art research results on CMOS MEMS are covered.

  16. SpatEntropy: Spatial Entropy Measures in R

    OpenAIRE

    Altieri, Linda; Cocchi, Daniela; Roli, Giulia

    2018-01-01

    This article illustrates how to measure the heterogeneity of spatial data presenting a finite number of categories via computation of spatial entropy. The R package SpatEntropy contains functions for the computation of entropy and spatial entropy measures. The extension to spatial entropy measures is a unique feature of SpatEntropy. In addition to the traditional version of Shannon's entropy, the package includes Batty's spatial entropy, O'Neill's entropy, Li and Reynolds' contagion index, Ka...

  17. Wafer-Level Packaging Method for RF MEMS Applications Using Pre-Patterned BCB Polymer

    OpenAIRE

    Zhuhao Gong; Yulong Zhang; Xin Guo; Zewen Liu

    2018-01-01

    A radio-frequency micro-electro-mechanical system (RF MEMS) wafer-level packaging (WLP) method using pre-patterned benzo-cyclo-butene (BCB) polymers with a high-resistivity silicon cap is proposed to achieve high bonding quality and excellent RF performance. In this process, the BCB polymer was pre-defined to form the sealing ring and bonding layer by the spin-coating and patterning of photosensitive BCB before the cavity formation. During anisotropic wet etching of the silicon wafer to gener...

  18. Estimation of Lithological Classification in Taipei Basin: A Bayesian Maximum Entropy Method

    Science.gov (United States)

    Wu, Meng-Ting; Lin, Yuan-Chien; Yu, Hwa-Lung

    2015-04-01

    In environmental or other scientific applications, we must have a certain understanding of geological lithological composition. Because of restrictions of real conditions, only limited amount of data can be acquired. To find out the lithological distribution in the study area, many spatial statistical methods used to estimate the lithological composition on unsampled points or grids. This study applied the Bayesian Maximum Entropy (BME method), which is an emerging method of the geological spatiotemporal statistics field. The BME method can identify the spatiotemporal correlation of the data, and combine not only the hard data but the soft data to improve estimation. The data of lithological classification is discrete categorical data. Therefore, this research applied Categorical BME to establish a complete three-dimensional Lithological estimation model. Apply the limited hard data from the cores and the soft data generated from the geological dating data and the virtual wells to estimate the three-dimensional lithological classification in Taipei Basin. Keywords: Categorical Bayesian Maximum Entropy method, Lithological Classification, Hydrogeological Setting

  19. A Novel Temperature Compensation Method for a MEMS Gyroscope Oriented on a Periphery Circuit

    Directory of Open Access Journals (Sweden)

    Huiliang Cao

    2013-09-01

    Full Text Available This paper investigates temperature compensation methods used for the scale factor and bias of the MEMS gyroscope within the temperature range from − 40°C to 60°C. The structure and periphery monitor circuit are introduced. Then the determinant elements of the MEMS gyroscope's scale factor are analysed and the results indicate that scale factor is directly proportional to drive amplitude and sense loop gain and is inversely proportional to the frequency gap between two modes. After that, the compensation methods are proposed, the thermal resistor's positive temperature coefficient (tempco is utilized to calibrate the scale factor's tempco through regulating the drive mode amplitude and the sense loop gain, and each method is applied respectively and the results are contrasted. The test results of the two specimens express that the most effective compensation method could decrease the scale factor's tempco from 693ppm/°C (640ppm/°C to 250ppm/°C (257ppm/°C, improving it by 63.9% (59.8%. Finally, a method of declining bias's tempco is investigated and implemented after scale factor compensation. A summator with a thermal resistor is utilized at the output level and decreases the bias's tempco from 103.89°/h/°C (100.78°/h/°C to 9.70°/h/°C (12°/h/°C improving it by 90.7% (88%. Repeat tests are performed based on two specimens to prove the repeatability and reproducibility of the methods.

  20. Acoustic Source Localization via Subspace Based Method Using Small Aperture MEMS Arrays

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2014-01-01

    Full Text Available Small aperture microphone arrays provide many advantages for portable devices and hearing aid equipment. In this paper, a subspace based localization method is proposed for acoustic source using small aperture arrays. The effects of array aperture on localization are analyzed by using array response (array manifold. Besides array aperture, the frequency of acoustic source and the variance of signal power are simulated to demonstrate how to optimize localization performance, which is carried out by introducing frequency error with the proposed method. The proposed method for 5 mm array aperture is validated by simulations and experiments with MEMS microphone arrays. Different types of acoustic sources can be localized with the highest precision of 6 degrees even in the presence of wind noise and other noises. Furthermore, the proposed method reduces the computational complexity compared with other methods.

  1. Adjoint entropy vs topological entropy

    OpenAIRE

    Giordano Bruno, Anna

    2012-01-01

    Recently the adjoint algebraic entropy of endomorphisms of abelian groups was introduced and studied. We generalize the notion of adjoint entropy to continuous endomorphisms of topological abelian groups. Indeed, the adjoint algebraic entropy is defined using the family of all finite-index subgroups, while we take only the subfamily of all open finite-index subgroups to define the topological adjoint entropy. This allows us to compare the (topological) adjoint entropy with the known topologic...

  2. SU-8 Based MEMS Process with Two Metal Layers using α-Si as a Sacrificial Material

    KAUST Repository

    Ramadan, Khaled S.

    2012-01-01

    MEMS applications. α-Si can be deposited at large thicknesses for MEMS applications and also can be released in a dry method using XeF2 which can solve stiction problems related to MEMS applications. In this thesis, an SU-8 MEMS process is developed

  3. Wafer level packaging of MEMS

    International Nuclear Information System (INIS)

    Esashi, Masayoshi

    2008-01-01

    Wafer level packaging plays many important roles for MEMS (micro electro mechanical systems), including cost, yield and reliability. MEMS structures on silicon chips are encapsulated between bonded wafers or by surface micromachining, and electrical interconnections are made from the cavity. Bonding at the interface, such as glass–Si anodic bonding and metal-to-metal bonding, requires electrical interconnection through the lid vias in many cases. On the other hand, lateral electrical interconnections on the surface of the chip are used for bonding with intermediate melting materials, such as low melting point glass and solder. The cavity formed by surface micromachining is made using sacrificial etching, and the openings needed for the sacrificial etching are plugged using deposition sealing methods. Vacuum packaging methods and the structures for electrical feedthrough for the interconnection are discussed in this review. (topical review)

  4. Upper entropy axioms and lower entropy axioms

    International Nuclear Information System (INIS)

    Guo, Jin-Li; Suo, Qi

    2015-01-01

    The paper suggests the concepts of an upper entropy and a lower entropy. We propose a new axiomatic definition, namely, upper entropy axioms, inspired by axioms of metric spaces, and also formulate lower entropy axioms. We also develop weak upper entropy axioms and weak lower entropy axioms. Their conditions are weaker than those of Shannon–Khinchin axioms and Tsallis axioms, while these conditions are stronger than those of the axiomatics based on the first three Shannon–Khinchin axioms. The subadditivity and strong subadditivity of entropy are obtained in the new axiomatics. Tsallis statistics is a special case of satisfying our axioms. Moreover, different forms of information measures, such as Shannon entropy, Daroczy entropy, Tsallis entropy and other entropies, can be unified under the same axiomatics

  5. Quantifying selection and diversity in viruses by entropy methods, with application to the haemagglutinin of H3N2 influenza

    Science.gov (United States)

    Pan, Keyao; Deem, Michael W.

    2011-01-01

    Many viruses evolve rapidly. For example, haemagglutinin (HA) of the H3N2 influenza A virus evolves to escape antibody binding. This evolution of the H3N2 virus means that people who have previously been exposed to an influenza strain may be infected by a newly emerged virus. In this paper, we use Shannon entropy and relative entropy to measure the diversity and selection pressure by an antibody in each amino acid site of H3 HA between the 1992–1993 season and the 2009–2010 season. Shannon entropy and relative entropy are two independent state variables that we use to characterize H3N2 evolution. The entropy method estimates future H3N2 evolution and migration using currently available H3 HA sequences. First, we show that the rate of evolution increases with the virus diversity in the current season. The Shannon entropy of the sequence in the current season predicts relative entropy between sequences in the current season and those in the next season. Second, a global migration pattern of H3N2 is assembled by comparing the relative entropy flows of sequences sampled in China, Japan, the USA and Europe. We verify this entropy method by describing two aspects of historical H3N2 evolution. First, we identify 54 amino acid sites in HA that have evolved in the past to evade the immune system. Second, the entropy method shows that epitopes A and B on the top of HA evolve most vigorously to escape antibody binding. Our work provides a novel entropy-based method to predict and quantify future H3N2 evolution and to describe the evolutionary history of H3N2. PMID:21543352

  6. Nonsymmetric entropy and maximum nonsymmetric entropy principle

    International Nuclear Information System (INIS)

    Liu Chengshi

    2009-01-01

    Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.

  7. MEMS Reliability Assurance Activities at JPL

    Science.gov (United States)

    Kayali, S.; Lawton, R.; Stark, B.

    2000-01-01

    An overview of Microelectromechanical Systems (MEMS) reliability assurance and qualification activities at JPL is presented along with the a discussion of characterization of MEMS structures implemented on single crystal silicon, polycrystalline silicon, CMOS, and LIGA processes. Additionally, common failure modes and mechanisms affecting MEMS structures, including radiation effects, are discussed. Common reliability and qualification practices contained in the MEMS Reliability Assurance Guideline are also presented.

  8. Challenges in the Packaging of MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Malshe, A.P.; Singh, S.B.; Eaton, W.P.; O' Neal, C.; Brown, W.D.; Miller, W.M.

    1999-03-26

    The packaging of Micro-Electro-Mechanical Systems (MEMS) is a field of great importance to anyone using or manufacturing sensors, consumer products, or military applications. Currently much work has been done in the design and fabrication of MEMS devices but insufficient research and few publications have been completed on the packaging of these devices. This is despite the fact that packaging is a very large percentage of the total cost of MEMS devices. The main difference between IC packaging and MEMS packaging is that MEMS packaging is almost always application specific and greatly affected by its environment and packaging techniques such as die handling, die attach processes, and lid sealing. Many of these aspects are directly related to the materials used in the packaging processes. MEMS devices that are functional in wafer form can be rendered inoperable after packaging. MEMS dies must be handled only from the chip sides so features on the top surface are not damaged. This eliminates most current die pick-and-place fixtures. Die attach materials are key to MEMS packaging. Using hard die attach solders can create high stresses in the MEMS devices, which can affect their operation greatly. Low-stress epoxies can be high-outgassing, which can also affect device performance. Also, a low modulus die attach can allow the die to move during ultrasonic wirebonding resulting to low wirebond strength. Another source of residual stress is the lid sealing process. Most MEMS based sensors and devices require a hermetically sealed package. This can be done by parallel seam welding the package lid, but at the cost of further induced stress on the die. Another issue of MEMS packaging is the media compatibility of the packaged device. MEMS unlike ICS often interface with their environment, which could be high pressure or corrosive. The main conclusion we can draw about MEMS packaging is that the package affects the performance and reliability of the MEMS devices. There is a

  9. Controlling the Shannon Entropy of Quantum Systems

    Science.gov (United States)

    Xing, Yifan; Wu, Jun

    2013-01-01

    This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking. PMID:23818819

  10. Controlling the Shannon Entropy of Quantum Systems

    Directory of Open Access Journals (Sweden)

    Yifan Xing

    2013-01-01

    Full Text Available This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking.

  11. Entropy, neutro-entropy and anti-entropy for neutrosophic information

    OpenAIRE

    Vasile Patrascu

    2017-01-01

    This approach presents a multi-valued representation of the neutrosophic information. It highlights the link between the bifuzzy information and neutrosophic one. The constructed deca-valued structure shows the neutrosophic information complexity. This deca-valued structure led to construction of two new concepts for the neutrosophic information: neutro-entropy and anti-entropy. These two concepts are added to the two existing: entropy and non-entropy. Thus, we obtained the following triad: e...

  12. Hermeticity testing of MEMS and microelectronic packages

    CERN Document Server

    Costello, Suzanne

    2013-01-01

    Packaging of microelectronics has been developing since the invention of the transistor in 1947. With the increasing complexity and decreasing size of the die, packaging requirements have continued to change. A step change in package requirements came with the introduction of the Micro-Electro-Mechanical System (MEMS) whereby interactions with the external environment are, in some cases, required.This resource is a rapid, definitive reference on hermetic packaging for the MEMS and microelectronics industry, giving practical guidance on traditional and newly developed test methods. This book in

  13. Physical entropy, information entropy and their evolution equations

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Inspired by the evolution equation of nonequilibrium statistical physics entropy and the concise statistical formula of the entropy production rate, we develop a theory of the dynamic information entropy and build a nonlinear evolution equation of the information entropy density changing in time and state variable space. Its mathematical form and physical meaning are similar to the evolution equation of the physical entropy: The time rate of change of information entropy density originates together from drift, diffusion and production. The concise statistical formula of information entropy production rate is similar to that of physical entropy also. Furthermore, we study the similarity and difference between physical entropy and information entropy and the possible unification of the two statistical entropies, and discuss the relationship among the principle of entropy increase, the principle of equilibrium maximum entropy and the principle of maximum information entropy as well as the connection between them and the entropy evolution equation.

  14. Incommensurate modulations made visible by the Maximum Entropy Method in superspace

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; van Smaalen, S.

    2004-01-01

    Roč. 219, - (2004), s. 719-729 ISSN 0044-2968 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : Maximum Entropy Method * modulated structures * charge density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.390, year: 2004

  15. Optical inspection of hidden MEMS structures

    Science.gov (United States)

    Krauter, Johann; Gronle, Marc; Osten, Wolfgang

    2017-06-01

    Micro-electro-mechanical system's (MEMS) applications have greatly expanded over the recent years, and the MEMS industry has grown almost exponentially. One of the strongest drivers are the automotive and consumer markets. A 100% test is necessary especially in the production of automotive MEMS sensors since they are subject to safety relevant functions. This inspection should be carried out before dicing and packaging since more than 90% of the production costs are incurred during these steps. An electrical test is currently being carried out with each MEMS component. In the case of a malfunction, the defect can not be located on the wafer because the MEMS are no longer optically accessible due to the encapsulation. This paper presents a low coherence interferometer for the topography measurement of MEMS structures located within the wafer stack. Here, a high axial and lateral resolution is necessary to identify defects such as stuck or bent MEMS fingers. First, the boundary conditions for an optical inspection system will be discussed. The setup is then shown with some exemplary measurements.

  16. Multidimensional scaling analysis of financial time series based on modified cross-sample entropy methods

    Science.gov (United States)

    He, Jiayi; Shang, Pengjian; Xiong, Hui

    2018-06-01

    Stocks, as the concrete manifestation of financial time series with plenty of potential information, are often used in the study of financial time series. In this paper, we utilize the stock data to recognize their patterns through out the dissimilarity matrix based on modified cross-sample entropy, then three-dimensional perceptual maps of the results are provided through multidimensional scaling method. Two modified multidimensional scaling methods are proposed in this paper, that is, multidimensional scaling based on Kronecker-delta cross-sample entropy (MDS-KCSE) and multidimensional scaling based on permutation cross-sample entropy (MDS-PCSE). These two methods use Kronecker-delta based cross-sample entropy and permutation based cross-sample entropy to replace the distance or dissimilarity measurement in classical multidimensional scaling (MDS). Multidimensional scaling based on Chebyshev distance (MDSC) is employed to provide a reference for comparisons. Our analysis reveals a clear clustering both in synthetic data and 18 indices from diverse stock markets. It implies that time series generated by the same model are easier to have similar irregularity than others, and the difference in the stock index, which is caused by the country or region and the different financial policies, can reflect the irregularity in the data. In the synthetic data experiments, not only the time series generated by different models can be distinguished, the one generated under different parameters of the same model can also be detected. In the financial data experiment, the stock indices are clearly divided into five groups. Through analysis, we find that they correspond to five regions, respectively, that is, Europe, North America, South America, Asian-Pacific (with the exception of mainland China), mainland China and Russia. The results also demonstrate that MDS-KCSE and MDS-PCSE provide more effective divisions in experiments than MDSC.

  17. Weighted fractional permutation entropy and fractional sample entropy for nonlinear Potts financial dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kaixuan, E-mail: kaixuanxubjtu@yeah.net; Wang, Jun

    2017-02-26

    In this paper, recently introduced permutation entropy and sample entropy are further developed to the fractional cases, weighted fractional permutation entropy (WFPE) and fractional sample entropy (FSE). The fractional order generalization of information entropy is utilized in the above two complexity approaches, to detect the statistical characteristics of fractional order information in complex systems. The effectiveness analysis of proposed methods on the synthetic data and the real-world data reveals that tuning the fractional order allows a high sensitivity and more accurate characterization to the signal evolution, which is useful in describing the dynamics of complex systems. Moreover, the numerical research on nonlinear complexity behaviors is compared between the returns series of Potts financial model and the actual stock markets. And the empirical results confirm the feasibility of the proposed model. - Highlights: • Two new entropy approaches for estimation of nonlinear complexity are proposed for the financial market. • Effectiveness analysis of proposed methods is presented and their respective features are studied. • Empirical research of proposed analysis on seven world financial market indices. • Numerical simulation of Potts financial dynamics is preformed for nonlinear complexity behaviors.

  18. Weighted fractional permutation entropy and fractional sample entropy for nonlinear Potts financial dynamics

    International Nuclear Information System (INIS)

    Xu, Kaixuan; Wang, Jun

    2017-01-01

    In this paper, recently introduced permutation entropy and sample entropy are further developed to the fractional cases, weighted fractional permutation entropy (WFPE) and fractional sample entropy (FSE). The fractional order generalization of information entropy is utilized in the above two complexity approaches, to detect the statistical characteristics of fractional order information in complex systems. The effectiveness analysis of proposed methods on the synthetic data and the real-world data reveals that tuning the fractional order allows a high sensitivity and more accurate characterization to the signal evolution, which is useful in describing the dynamics of complex systems. Moreover, the numerical research on nonlinear complexity behaviors is compared between the returns series of Potts financial model and the actual stock markets. And the empirical results confirm the feasibility of the proposed model. - Highlights: • Two new entropy approaches for estimation of nonlinear complexity are proposed for the financial market. • Effectiveness analysis of proposed methods is presented and their respective features are studied. • Empirical research of proposed analysis on seven world financial market indices. • Numerical simulation of Potts financial dynamics is preformed for nonlinear complexity behaviors.

  19. Gradient Dynamics and Entropy Production Maximization

    Science.gov (United States)

    Janečka, Adam; Pavelka, Michal

    2018-01-01

    We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.

  20. Uncertainty quantification in capacitive RF MEMS switches

    Science.gov (United States)

    Pax, Benjamin J.

    Development of radio frequency micro electrical-mechanical systems (RF MEMS) has led to novel approaches to implement electrical circuitry. The introduction of capacitive MEMS switches, in particular, has shown promise in low-loss, low-power devices. However, the promise of MEMS switches has not yet been completely realized. RF-MEMS switches are known to fail after only a few months of operation, and nominally similar designs show wide variability in lifetime. Modeling switch operation using nominal or as-designed parameters cannot predict the statistical spread in the number of cycles to failure, and probabilistic methods are necessary. A Bayesian framework for calibration, validation and prediction offers an integrated approach to quantifying the uncertainty in predictions of MEMS switch performance. The objective of this thesis is to use the Bayesian framework to predict the creep-related deflection of the PRISM RF-MEMS switch over several thousand hours of operation. The PRISM switch used in this thesis is the focus of research at Purdue's PRISM center, and is a capacitive contacting RF-MEMS switch. It employs a fixed-fixed nickel membrane which is electrostatically actuated by applying voltage between the membrane and a pull-down electrode. Creep plays a central role in the reliability of this switch. The focus of this thesis is on the creep model, which is calibrated against experimental data measured for a frog-leg varactor fabricated and characterized at Purdue University. Creep plasticity is modeled using plate element theory with electrostatic forces being generated using either parallel plate approximations where appropriate, or solving for the full 3D potential field. For the latter, structure-electrostatics interaction is determined through immersed boundary method. A probabilistic framework using generalized polynomial chaos (gPC) is used to create surrogate models to mitigate the costly full physics simulations, and Bayesian calibration and forward

  1. Entropy, neutro-entropy and anti-entropy for neutrosophic information

    OpenAIRE

    Vasile Patrascu

    2017-01-01

    This article shows a deca-valued representation of neutrosophic information in which are defined the following features: truth, falsity, weak truth, weak falsity, ignorance, contradiction, saturation, neutrality, ambiguity and hesitation. Using these features, there are constructed computing formulas for entropy, neutro-entropy and anti-entropy.

  2. Use of the maximum entropy method in X-ray astronomy

    International Nuclear Information System (INIS)

    Willingale, R.

    1981-01-01

    An algorithm used to apply the maximum entropy method in X-ray astronomy is described. It is easy to programme on a digital computer and fast enough to allow processing of two-dimensional images. The method gives good noise suppression without loss of instrumental resolution and has been successfully applied to several data analysis problems in X-ray astronomy. The restoration of a high-resolution image from the Einstein Observatory demonstrates the use of the algorithm. (author)

  3. MEMS fluidic actuator

    Science.gov (United States)

    Kholwadwala, Deepesh K [Albuquerque, NM; Johnston, Gabriel A [Trophy Club, TX; Rohrer, Brandon R [Albuquerque, NM; Galambos, Paul C [Albuquerque, NM; Okandan, Murat [Albuquerque, NM

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  4. MEMS cost analysis from laboratory to industry

    CERN Document Server

    Freng, Ron Lawes

    2016-01-01

    The World of MEMS; Chapter 2: Basic Fabrication Processes; Chapter 3: Surface Microengineering. High Aspect Ratio Microengineering; Chapter 5: MEMS Testing; Chapter 6: MEMS Packaging. Clean Rooms, Buildings and Plant; Chapter 8: The MEMSCOST Spreadsheet; Chapter 9: Product Costs - Accelerometers. Product Costs - Microphones. MEMS Foundries. Financial Reporting and Analysis. Conclusions.

  5. A Performance Improvement Method for Low-Cost Land Vehicle GPS/MEMS-INS Attitude Determination

    Science.gov (United States)

    Cong, Li; Li, Ercui; Qin, Honglei; Ling, Keck Voon; Xue, Rui

    2015-01-01

    Global positioning system (GPS) technology is well suited for attitude determination. However, in land vehicle application, low-cost single frequency GPS receivers which have low measurement quality are often used, and external factors such as multipath and low satellite visibility in the densely built-up urban environment further degrade the quality of the GPS measurements. Due to the low-quality receivers used and the challenging urban environment, the success rate of the single epoch ambiguity resolution for dynamic attitude determination is usually quite low. In this paper, a micro-electro-mechanical system (MEMS)—inertial navigation system (INS)-aided ambiguity resolution method is proposed to improve the GPS attitude determination performance, which is particularly suitable for land vehicle attitude determination. First, the INS calculated baseline vector is augmented with the GPS carrier phase and code measurements. This improves the ambiguity dilution of precision (ADOP), resulting in better quality of the unconstrained float solution. Second, the undesirable float solutions caused by large measurement errors are further filtered and replaced using the INS-aided ambiguity function method (AFM). The fixed solutions are then obtained by the constrained least squares ambiguity decorrelation (CLAMBDA) algorithm. Finally, the GPS/MEMS-INS integration is realized by the use of a Kalman filter. Theoretical analysis of the ADOP is given and experimental results demonstrate that our proposed method can significantly improve the quality of the float ambiguity solution, leading to high success rate and better accuracy of attitude determination. PMID:25760057

  6. Direct comparison of phase-sensitive vibrational sum frequency generation with maximum entropy method: case study of water.

    Science.gov (United States)

    de Beer, Alex G F; Samson, Jean-Sebastièn; Hua, Wei; Huang, Zishuai; Chen, Xiangke; Allen, Heather C; Roke, Sylvie

    2011-12-14

    We present a direct comparison of phase sensitive sum-frequency generation experiments with phase reconstruction obtained by the maximum entropy method. We show that both methods lead to the same complex spectrum. Furthermore, we discuss the strengths and weaknesses of each of these methods, analyzing possible sources of experimental and analytical errors. A simulation program for maximum entropy phase reconstruction is available at: http://lbp.epfl.ch/. © 2011 American Institute of Physics

  7. Nondestructive surface profiling of hidden MEMS using an infrared low-coherence interferometric microscope

    Science.gov (United States)

    Krauter, Johann; Osten, Wolfgang

    2018-03-01

    There are a wide range of applications for micro-electro-mechanical systems (MEMS). The automotive and consumer market is the strongest driver for the growing MEMS industry. A 100 % test of MEMS is particularly necessary since these are often used for safety-related purposes such as the ESP (Electronic Stability Program) system. The production of MEMS is a fully automated process that generates 90 % of the costs during the packaging and dicing steps. Nowadays, an electrical test is carried out on each individual MEMS component before these steps. However, after encapsulation, MEMS are opaque to visible light and other defects cannot be detected. Therefore, we apply an infrared low-coherence interferometer for the topography measurement of those hidden structures. A lock-in algorithm-based method is shown to calculate the object height and to reduce ghost steps due to the 2π -unambiguity. Finally, measurements of different MEMS-based sensors are presented.

  8. Novel 3D modeling methods for virtual fabrication and EDA compatible design of MEMS via parametric libraries

    International Nuclear Information System (INIS)

    Schröpfer, Gerold; Lorenz, Gunar; Rouvillois, Stéphane; Breit, Stephen

    2010-01-01

    This paper provides a brief summary of the state-of-the-art of MEMS-specific modeling techniques and describes the validation of new models for a parametric component library. Two recently developed 3D modeling tools are described in more detail. The first one captures a methodology for designing MEMS devices and simulating them together with integrated electronics within a standard electronic design automation (EDA) environment. The MEMS designer can construct the MEMS model directly in a 3D view. The resulting 3D model differs from a typical feature-based 3D CAD modeling tool in that there is an underlying behavioral model and parametric layout associated with each MEMS component. The model of the complete MEMS device that is shared with the standard EDA environment can be fully parameterized with respect to manufacturing- and design-dependent variables. Another recent innovation is a process modeling tool that allows accurate and highly realistic visualization of the step-by-step creation of 3D micro-fabricated devices. The novelty of the tool lies in its use of voxels (3D pixels) rather than conventional 3D CAD techniques to represent the 3D geometry. Case studies for experimental devices are presented showing how the examination of these virtual prototypes can reveal design errors before mask tape out, support process development before actual fabrication and also enable failure analysis after manufacturing.

  9. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

    Directory of Open Access Journals (Sweden)

    Yongxin Chou

    2017-01-01

    Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

  10. Modeling nonlinearities in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

    2013-08-01

    We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

  11. A Teaching - Learning Framework for MEMS Education

    International Nuclear Information System (INIS)

    Sheeparamatti, B G; Angadi, S A; Sheeparamatti, R B; Kadadevaramath, J S

    2006-01-01

    Micro-Electro-Mechanical Systems (MEMS) technology has been identified as one of the most promising technologies in the 21st century. MEMS technology has opened up a wide array of unforeseen applications. Hence it is necessary to train the technocrats of tomorrow in this emerging field to meet the industrial/societal demands. The drive behind fostering of MEMS technology is the reduction in the cost, size, weight, and power consumption of the sensors, actuators, and associated electronics. MEMS is a multidisciplinary engineering and basic science area which includes electrical engineering, mechanical engineering, material science and biomedical engineering. Hence MEMS education needs a special approach to prepare the technocrats for a career in MEMS. The modern education methodology using computer based training systems (CBTS) with embedded modeling and simulation tools will help in this direction. The availability of computer based learning resources such as MATLAB, ANSYS/Multiphysics and rapid prototyping tools have contributed to proposition of an efficient teaching-learning framework for MEMS education presented in this paper. This paper proposes a conceptual framework for teaching/learning MEMS in the current technical education scenario

  12. Improving Distributed Denial of Service (DDOS Detection using Entropy Method in Software Defined Network (SDN

    Directory of Open Access Journals (Sweden)

    Maman Abdurohman

    2017-12-01

    Full Text Available This research proposed a new method to enhance Distributed Denial of Service (DDoS detection attack on Software Defined Network (SDN environment. This research utilized the OpenFlow controller of SDN for DDoS attack detection using modified method and regarding entropy value. The new method would check whether the traffic was a normal traffic or DDoS attack by measuring the randomness of the packets. This method consisted of two steps, detecting attack and checking the entropy. The result shows that the new method can reduce false positive when there is a temporary and sudden increase in normal traffic. The new method succeeds in not detecting this as a DDoS attack. Compared to previous methods, this proposed method can enhance DDoS attack detection on SDN environment.

  13. Micro electromechanical systems (MEMS) for mechanical engineers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. P., LLNL

    1996-11-18

    The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, the analysis of the mechanical system, the design of testing apparatus, the implementation of analytical tools, and the packaging process. Every single aspect of mechanical engineering is being utilized in the MEMS field today, however, the impact could be more substantial if more mechanical engineers are involved in the systems level designing. In this paper, an attempt is made to create the pathways for a mechanical engineer to enter in the MEMS field. Examples of application in optics and medical devices will be used to illustrate how mechanical

  14. European MEMS foundries

    Science.gov (United States)

    Salomon, Patric R.

    2003-01-01

    According to the latest release of the NEXUS market study, the market for MEMS or Microsystems Technology (MST) is predicted to grow to $68B by the year 2005, with systems containing these components generating even higher revenues and growth. The latest advances in MST/MEMS technology have enabled the design of a new generation of microsystems that are smaller, cheaper, more reliable, and consume less power. These integrated systems bring together numerous analog/mixed signal microelectronics blocks and MEMS functions on a single chip or on two or more chips assembled within an integrated package. In spite of all these advances in technology and manufacturing, a system manufacturer either faces a substantial up-front R&D investment to create his own infrastructure and expertise, or he can use design and foundry services to get the initial product into the marketplace fast and with an affordable investment. Once he has a viable product, he can still think about his own manufacturing efforts and investments to obtain an optimized high volume manufacturing for the specific product. One of the barriers to successful exploitation of MEMS/MST technology has been the lack of access to industrial foundries capable of producing certified microsystems devices in commercial quantities, including packaging and test. This paper discusses Multi-project wafer (MPW) runs, requirements for foundries and gives some examples of foundry business models. Furthermore, this paper will give an overview on MST/MEMS services that are available in Europe, including pure commercial activities, European project activities (e.g. Europractice), and some academic services.

  15. Low Streamflow Forcasting using Minimum Relative Entropy

    Science.gov (United States)

    Cui, H.; Singh, V. P.

    2013-12-01

    Minimum relative entropy spectral analysis is derived in this study, and applied to forecast streamflow time series. Proposed method extends the autocorrelation in the manner that the relative entropy of underlying process is minimized so that time series data can be forecasted. Different prior estimation, such as uniform, exponential and Gaussian assumption, is taken to estimate the spectral density depending on the autocorrelation structure. Seasonal and nonseasonal low streamflow series obtained from Colorado River (Texas) under draught condition is successfully forecasted using proposed method. Minimum relative entropy determines spectral of low streamflow series with higher resolution than conventional method. Forecasted streamflow is compared to the prediction using Burg's maximum entropy spectral analysis (MESA) and Configurational entropy. The advantage and disadvantage of each method in forecasting low streamflow is discussed.

  16. MEMS-based Circuits and Systems for Wireless Communication

    CERN Document Server

    Kaiser, Andreas

    2013-01-01

    MEMS-based Circuits and Systems for Wireless Communication provides comprehensive coverage of RF-MEMS technology from device to system level. This edited volume places emphasis on how system performance for radio frequency applications can be leveraged by Micro-Electro-Mechanical Systems (MEMS). Coverage also extends to innovative MEMS-aware radio architectures that push the potential of MEMS technology further ahead.  This work presents a broad overview of the technology from MEMS devices (mainly BAW and Si MEMS resonators) to basic circuits, such as oscillators and filters, and finally complete systems such as ultra-low-power MEMS-based radios. Contributions from leading experts around the world are organized in three parts. Part I introduces RF-MEMS technology, devices and modeling and includes a prospective outlook on ongoing developments towards Nano-Electro-Mechanical Systems (NEMS) and phononic crystals. Device properties and models are presented in a circuit oriented perspective. Part II focusses on ...

  17. Laser-heating wire bonding on MEMS packaging

    Directory of Open Access Journals (Sweden)

    Yuetao Liu

    2014-02-01

    Full Text Available Making connections is critical in fabrication of MEMS (Micro-Electro-Mechanical Systems. It is also complicated, because the temperature during joining affects both the bond produced and the structure and mechanical properties of the moving parts of the device. Specifications for MEMS packaging require that the temperature not exceed 240 °C. However, usually, temperatures can reach up to 300 °C during conventional thermosonic wire bonding. Such a temperature will change the distribution of dopants in CMOS (Complementary Metal Oxide Semiconductor circuits. In this paper we propose a new heating process. A semiconductor laser (wavelength 808 nm is suggested as the thermal source for wire bonding. The thermal field of this setup was analyzed, and specific mathematical models of the field were built. Experimental results show that the heating can be focused on the bonding pad, and that much lower heat conduction occurs, compared with that during the normal heating method. The bond strength increases with increasing laser power. The bond strengths obtained with laser heating are slightly lower than those obtained with the normal heating method, but can still meet the strength requirements for MEMS.

  18. MEMS linear and nonlinear statics and dynamics

    CERN Document Server

    Younis, Mohammad I

    2011-01-01

    MEMS Linear and Nonlinear Statics and Dynamics presents the necessary analytical and computational tools for MEMS designers to model and simulate most known MEMS devices, structures, and phenomena. This book also provides an in-depth analysis and treatment of the most common static and dynamic phenomena in MEMS that are encountered by engineers. Coverage also includes nonlinear modeling approaches to modeling various MEMS phenomena of a nonlinear nature, such as those due to electrostatic forces, squeeze-film damping, and large deflection of structures. The book also: Includes examples of nume

  19. Maximum Entropy Method in Moessbauer Spectroscopy - a Problem of Magnetic Texture

    International Nuclear Information System (INIS)

    Satula, D.; Szymanski, K.; Dobrzynski, L.

    2011-01-01

    A reconstruction of the three dimensional distribution of the hyperfine magnetic field, isomer shift and texture parameter z from the Moessbauer spectra by the maximum entropy method is presented. The method was tested on the simulated spectrum consisting of two Gaussian hyperfine field distributions with different values of the texture parameters. It is shown that proper prior has to be chosen in order to arrive at the physically meaningful results. (authors)

  20. EEG entropy measures in anesthesia

    Science.gov (United States)

    Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

    2015-01-01

    Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation

  1. EEG entropy measures in anesthesia

    Directory of Open Access Journals (Sweden)

    Zhenhu eLiang

    2015-02-01

    Full Text Available Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs’ effect is lacking. In this study, we compare the capability of twelve entropy indices for monitoring depth of anesthesia (DoA and detecting the burst suppression pattern (BSP, in anesthesia induced by GA-BAergic agents.Methods: Twelve indices were investigated, namely Response Entropy (RE and State entropy (SE, three wavelet entropy (WE measures (Shannon WE (SWE, Tsallis WE (TWE and Renyi WE (RWE, Hilbert-Huang spectral entropy (HHSE, approximate entropy (ApEn, sample entropy (SampEn, Fuzzy entropy, and three permutation entropy (PE measures (Shannon PE (SPE, Tsallis PE (TPE and Renyi PE (RPE. Two EEG data sets from sevoflurane-induced and isoflu-rane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, phar-macokinetic / pharmacodynamic (PK/PD modeling and prediction probability analysis were applied. The multifractal detrended fluctuation analysis (MDFA as a non-entropy measure was compared.Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline vari-ability, higher coefficient of determination and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an ad-vantage in computation efficiency compared with MDFA.Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure.Significance: Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA.

  2. Surface chemistry and tribology of MEMS.

    Science.gov (United States)

    Maboudian, Roya; Carraro, Carlo

    2004-01-01

    The microscopic length scale and high surface-to-volume ratio, characteristic of microelectro-mechanical systems (MEMS), dictate that surface properties are of paramount importance. This review deals with the effects of surface chemical treatments on tribological properties (adhesion, friction, and wear) of MEMS devices. After a brief review of materials and processes that are utilized in MEMS technology, the relevant tribological and chemical issues are discussed. Various MEMS microinstruments are discussed, which are commonly employed to perform adhesion, friction, and wear measurements. The effects of different surface treatments on the reported tribological properties are discussed.

  3. Variations mechanism in entropy of wave height field and its relation with thermodynamic entropy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper gives a brief description of annual period and seasonal variation in the wave height field entropy in the northeastern Pacific. A calculation of the quantity of the, received by lithosphere systems in the northern hemisphere is introduced. The wave heat field entropy is compared with the difference in the quantity of the sun's radiation heat. Analysis on the transfer method, period and lag of this seasonal variation led to the conclusion that the annual period and seasonal variation in the entropy of the wave height field in the Northwestern Pacific is due to the seasonal variation of the sun's radiation heat. Furthermore, the inconsistency between thermodynamic entropy and information entropy was studied.

  4. Operator Splitting Methods for Degenerate Convection-Diffusion Equations I: Convergence and Entropy Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Holden, Helge; Karlsen, Kenneth H.; Lie, Knut-Andreas

    1999-10-01

    We present and analyze a numerical method for the solution of a class of scalar, multi-dimensional, nonlinear degenerate convection-diffusion equations. The method is based on operator splitting to separate the convective and the diffusive terms in the governing equation. The nonlinear, convective part is solved using front tracking and dimensional splitting, while the nonlinear diffusion equation is solved by a suitable difference scheme. We verify L{sup 1} compactness of the corresponding set of approximate solutions and derive precise entropy estimates. In particular, these results allow us to pass to the limit in our approximations and recover an entropy solution of the problem in question. The theory presented covers a large class of equations. Important subclasses are hyperbolic conservation laws, porous medium type equations, two-phase reservoir flow equations, and strongly degenerate equations coming from the recent theory of sedimentation-consolidation processes. A thorough numerical investigation of the method analyzed in this paper (and similar methods) is presented in a companion paper. (author)

  5. Application of the Maximum Entropy Method to Risk Analysis of Mergers and Acquisitions

    Science.gov (United States)

    Xie, Jigang; Song, Wenyun

    The maximum entropy (ME) method can be used to analyze the risk of mergers and acquisitions when only pre-acquisition information is available. A practical example of the risk analysis of China listed firms’ mergers and acquisitions is provided to testify the feasibility and practicality of the method.

  6. Calibration of an interfacial force microscope for MEMS metrology : FY08-09 activities.

    Energy Technology Data Exchange (ETDEWEB)

    Houston, Jack E.; Baker, Michael Sean; Crowson, Douglas A.; Mitchell, John Anthony; Moore, Nathan W.

    2009-10-01

    Progress in MEMS fabrication has enabled a wide variety of force and displacement sensing devices to be constructed. One device under intense development at Sandia is a passive shock switch, described elsewhere (Mitchell 2008). A goal of all MEMS devices, including the shock switch, is to achieve a high degree of reliability. This, in turn, requires systematic methods for validating device performance during each iteration of design. Once a design is finalized, suitable tools are needed to provide quality assurance for manufactured devices. To ensure device performance, measurements on these devices must be traceable to NIST standards. In addition, accurate metrology of MEMS components is needed to validate mechanical models that are used to design devices to accelerate development and meet emerging needs. Progress towards a NIST-traceable calibration method is described for a next-generation, 2D Interfacial Force Microscope (IFM) for applications in MEMS metrology and qualification. Discussed are the results of screening several suitable calibration methods and the known sources of uncertainty in each method.

  7. A Modified Entropy Generation Number for Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    This paper demonstrates the difference between the entropy generation number method proposed by Bejian and the method of entropy generation per unit amount of heat transferred in analyzing the ther-modynamic performance of heat exchangers,points out the reason for leading to the above difference.A modified entropy generation number for evaluating the irreversibility of heat exchangers is proposed which is in consistent with the entropy generation per unit amount of heat transferred in entropy generation analysis.The entropy generated by friction is also investigated.Results show that when the entropy generated by friction in heat exchangers in taken into account,there is a minimum total entropy generation number while the NTU and the ratio of heat capacity rates vary.The existence of this minimum is the prerequisite of heat exchanger optimization.

  8. Electrostatic MEMS devices with high reliability

    Science.gov (United States)

    Goldsmith, Charles L; Auciello, Orlando H; Sumant, Anirudha V; Mancini, Derrick C; Gudeman, Chris; Sampath, Suresh; Carlilse, John A; Carpick, Robert W; Hwang, James

    2015-02-24

    The present invention provides for an electrostatic microelectromechanical (MEMS) device comprising a dielectric layer separating a first conductor and a second conductor. The first conductor is moveable towards the second conductor, when a voltage is applied to the MEMS device. The dielectric layer recovers from dielectric charging failure almost immediately upon removal of the voltage from the MEMS device.

  9. Curvature Entropy for Curved Profile Generation

    Directory of Open Access Journals (Sweden)

    Koichiro Sato

    2012-03-01

    Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.

  10. Prediction of Protein Configurational Entropy (Popcoen).

    Science.gov (United States)

    Goethe, Martin; Gleixner, Jan; Fita, Ignacio; Rubi, J Miguel

    2018-03-13

    A knowledge-based method for configurational entropy prediction of proteins is presented; this methodology is extremely fast, compared to previous approaches, because it does not involve any type of configurational sampling. Instead, the configurational entropy of a query fold is estimated by evaluating an artificial neural network, which was trained on molecular-dynamics simulations of ∼1000 proteins. The predicted entropy can be incorporated into a large class of protein software based on cost-function minimization/evaluation, in which configurational entropy is currently neglected for performance reasons. Software of this type is used for all major protein tasks such as structure predictions, proteins design, NMR and X-ray refinement, docking, and mutation effect predictions. Integrating the predicted entropy can yield a significant accuracy increase as we show exemplarily for native-state identification with the prominent protein software FoldX. The method has been termed Popcoen for Prediction of Protein Configurational Entropy. An implementation is freely available at http://fmc.ub.edu/popcoen/ .

  11. A New Method of Reliability Evaluation Based on Wavelet Information Entropy for Equipment Condition Identification

    International Nuclear Information System (INIS)

    He, Z J; Zhang, X L; Chen, X F

    2012-01-01

    Aiming at reliability evaluation of condition identification of mechanical equipment, it is necessary to analyze condition monitoring information. A new method of reliability evaluation based on wavelet information entropy extracted from vibration signals of mechanical equipment is proposed. The method is quite different from traditional reliability evaluation models that are dependent on probability statistics analysis of large number sample data. The vibration signals of mechanical equipment were analyzed by means of second generation wavelet package (SGWP). We take relative energy in each frequency band of decomposed signal that equals a percentage of the whole signal energy as probability. Normalized information entropy (IE) is obtained based on the relative energy to describe uncertainty of a system instead of probability. The reliability degree is transformed by the normalized wavelet information entropy. A successful application has been achieved to evaluate the assembled quality reliability for a kind of dismountable disk-drum aero-engine. The reliability degree indicates the assembled quality satisfactorily.

  12. Stability analysis of explicit entropy viscosity methods for non-linear scalar conservation equations

    KAUST Repository

    Bonito, Andrea; Guermond, Jean-Luc; Popov, Bojan

    2013-01-01

    We establish the L2-stability of an entropy viscosity technique applied to nonlinear scalar conservation equations. First-and second-order explicit time-stepping techniques using continuous finite elements in space are considered. The method

  13. Critical Analysis of Non-Nuclear Electron-Density Maxima and the Maximum Entropy Method

    NARCIS (Netherlands)

    de Vries, R.Y.; Briels, Willem J.; Feil, D.; Feil, D.

    1996-01-01

    Experimental evidence for the existence of non-nuclear maxima in charge densities is questioned. It is shown that the non-nuclear maxima reported for silicon are artifacts of the maximum entropy method that was used to analyze the x-ray diffraction data. This method can be improved by the use of

  14. Algebraic topological entropy

    International Nuclear Information System (INIS)

    Hudetz, T.

    1989-01-01

    As a 'by-product' of the Connes-Narnhofer-Thirring theory of dynamical entropy for (originally non-Abelian) nuclear C * -algebras, the well-known variational principle for topological entropy is eqivalently reformulated in purly algebraically defined terms for (separable) Abelian C * -algebras. This 'algebraic variational principle' should not only nicely illustrate the 'feed-back' of methods developed for quantum dynamical systems to the classical theory, but it could also be proved directly by 'algebraic' methods and could thus further simplify the original proof of the variational principle (at least 'in principle'). 23 refs. (Author)

  15. Integrated design of MEMS

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Brissaud, Daniel

    2007-01-01

    Emerging technologies of Micro-Electromechanical Systems (MEMS) are applications such as airbag accelerometers. Micro-products present many physical differences from macro-products. Moreover, there is a high level of integration in multiple fields of physics with strongly coupled effects...... industrial immersion to propose a socio-technological description of the design process and MEMS design tools....

  16. Entropy correlation distance method. The Euro introduction effect on the Consumer Price Index

    Science.gov (United States)

    Miśkiewicz, Janusz

    2010-04-01

    The idea of entropy was introduced in thermodynamics, but it can be used in time series analysis. There are various ways to define and measure the entropy of a system. Here the so called Theil index, which is often used in economy and finance, is applied as it were an entropy measure. In this study the time series are remapped through the Theil index. Then the linear correlation coefficient between the remapped time series is evaluated as a function of time and time window size and the corresponding statistical distance is defined. The results are compared with the the usual correlation distance measure for the time series themselves. As an example this entropy correlation distance method (ECDM) is applied to several series, as those of the Consumer Price Index (CPI) in order to test some so called globalisation processes. Distance matrices are calculated in order to construct two network structures which are next analysed. The role of two different time scales introduced by the Theil index and a correlation coefficient is also discussed. The evolution of the mean distance between the most developed countries is presented and the globalisation periods of the prices discussed. It is finally shown that the evolution of mean distance between the most developed countries on several networks follows the process of introducing the European currency - the Euro. It is contrasted to the GDP based analysis. It is stressed that the entropy correlation distance measure is more suitable in detecting significant changes, like a globalisation process than the usual statistical (correlation based) measure.

  17. Piezoelectric MEMS resonators

    CERN Document Server

    Piazza, Gianluca

    2017-01-01

    This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associate...

  18. Research and Analysis of MEMS Switches in Different Frequency Bands

    Directory of Open Access Journals (Sweden)

    Wenchao Tian

    2018-04-01

    Full Text Available Due to their high isolation, low insertion loss, high linearity, and low power consumption, microelectromechanical systems (MEMS switches have drawn much attention from researchers in recent years. In this paper, we introduce the research status of MEMS switches in different bands and several reliability issues, such as dielectric charging, contact failure, and temperature instability. In this paper, some of the following methods to improve the performance of MEMS switches in high frequency are summarized: (1 utilizing combinations of several switches in series; (2 covering a float metal layer on the dielectric layer; (3 using dielectric layer materials with high dielectric constants and conductor materials with low resistance; (4 developing MEMS switches using T-match and π-match; (5 designing MEMS switches based on bipolar complementary metal–oxide–semiconductor (BiCMOS technology and reconfigurable MEMS’ surfaces; (6 employing thermal compensation structures, circularly symmetric structures, thermal buckle-beam actuators, molybdenum membrane, and thin-film packaging; (7 selecting Ultra-NanoCrystalline diamond or aluminum nitride dielectric materials and applying a bipolar driving voltage, stoppers, and a double-dielectric-layer structure; and (8 adopting gold alloying with carbon nanotubes (CNTs, hermetic and reliable packaging, and mN-level contact.

  19. Linear entropy in quantum phase space

    International Nuclear Information System (INIS)

    Rosales-Zarate, Laura E. C.; Drummond, P. D.

    2011-01-01

    We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. The preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.

  20. Linear entropy in quantum phase space

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Zarate, Laura E. C.; Drummond, P. D. [Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)

    2011-10-15

    We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. The preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.

  1. Adhesion aspects in MEMS/NEMS

    CERN Document Server

    Kim, Seong H; Mittal, Kash L

    2012-01-01

    Phenomena associated with the adhesion interaction of surfaces have been a critical aspect of micro- and nanosystem development and performance since the first MicroElectroMechanicalSystems(MEMS) were fabricated. These phenomena are ubiquitous in nature and are present in all systems, however MEMS devices are particularly sensitive to their effects owing to their small size and limited actuation force that can be generated. Extension of MEMS technology concepts to the nanoscale and development of NanoElectroMechanicalSystems(NEMS) will result in systems even more strongly influenced by surface

  2. Practical guide to RF-MEMS

    CERN Document Server

    Iannacci, Jacopo

    2013-01-01

    Closes the gap between hardcore-theoretical and purely experimental RF-MEMS books. The book covers, from a practical viewpoint, the most critical steps that have to be taken in order to develop novel RF-MEMS device concepts. Prototypical RF-MEMS devices, both including lumped components and complex networks, are presented at the beginning of the book as reference examples, and these are then discussed from different perspectives with regard to design, simulation, packaging, testing, and post-fabrication modeling. Theoretical concepts are introduced when necessary to complement the practical

  3. A six degrees of freedom mems manipulator

    NARCIS (Netherlands)

    de Jong, B.R.

    2006-01-01

    This thesis reports about a six degrees of freedom (DOF) precision manipulator in MEMS, concerning concept generation for the manipulator followed by design and fabrication (of parts) of the proposed manipulation concept in MEMS. Researching the abilities of 6 DOF precision manipulation in MEMS is

  4. A new entropy based method for computing software structural complexity

    CERN Document Server

    Roca, J L

    2002-01-01

    In this paper a new methodology for the evaluation of software structural complexity is described. It is based on the entropy evaluation of the random uniform response function associated with the so called software characteristic function SCF. The behavior of the SCF with the different software structures and their relationship with the number of inherent errors is investigated. It is also investigated how the entropy concept can be used to evaluate the complexity of a software structure considering the SCF as a canonical representation of the graph associated with the control flow diagram. The functions, parameters and algorithms that allow to carry out this evaluation are also introduced. After this analytic phase follows the experimental phase, verifying the consistency of the proposed metric and their boundary conditions. The conclusion is that the degree of software structural complexity can be measured as the entropy of the random uniform response function of the SCF. That entropy is in direct relation...

  5. Piezoelectric Lead Zirconate Titanate (PZT) Ring Shaped Contour-Mode MEMS Resonators

    Science.gov (United States)

    Kasambe, P. V.; Asgaonkar, V. V.; Bangera, A. D.; Lokre, A. S.; Rathod, S. S.; Bhoir, D. V.

    2018-02-01

    Flexibility in setting fundamental frequency of resonator independent of its motional resistance is one of the desired criteria in micro-electromechanical (MEMS) resonator design. It is observed that ring-shaped piezoelectric contour-mode MEMS resonators satisfy this design criterion than in case of rectangular plate MEMS resonators. Also ring-shaped contour-mode piezoelectric MEMS resonator has an advantage that its fundamental frequency is defined by in-plane dimensions, but they show variation of fundamental frequency with different Platinum (Pt) thickness referred as change in ratio of fNEW /fO . This paper presents the effects of variation in geometrical parameters and change in piezoelectric material on the resonant frequencies of Platinum piezoelectric-Aluminium ring-shaped contour-mode MEMS resonators and its electrical parameters. The proposed structure with Lead Zirconate Titanate (PZT) as the piezoelectric material was observed to be a piezoelectric material with minimal change in fundamental resonant frequency due to Platinum thickness variation. This structure was also found to exhibit extremely low motional resistance of 0.03 Ω as compared to the 31-35 Ω range obtained when using AlN as the piezoelectric material. CoventorWare 10 is used for the design, simulation and corresponding analysis of resonators which is Finite Element Method (FEM) analysis and design tool for MEMS devices.

  6. Design and Simulation of MEMS Devices using Interval Analysis

    International Nuclear Information System (INIS)

    Shanmugavalli, M; Uma, G; Vasuki, B; Umapathy, M

    2006-01-01

    Modeling and simulation of MEMS devices are used to optimize the design, to improve the performance of the device, to reduce time to market, to minimize development time and cost by avoiding unnecessary design cycles and foundry runs. The major design objectives in any device design, is to meet the required functional parameters and the reliability of the device. The functional parameters depend on the geometry of the structure, material properties and process parameters. All model parameters act as input to optimize the functional parameters. The major difficulty the designer faces is the dimensions and properties used in the simulation of the MEMS devices can not be exactly followed during fabrication. In order to overcome this problem, the designer must test the device in simulation for bound of parameters involved in it. The paper demonstrates the use of interval methods to assess the electromechanical behaviour of micro electromechanical systems (MEMS) under the presence of manufacturing and process uncertainties. Interval method guides the design of pullin voltage analysis of fixed-fixed beam to achieve a robust and reliable design in a most efficient way. The methods are implemented numerically using Coventorware and analytically using Intlab

  7. Thermoeconomic diagnosis and entropy generation paradox

    DEFF Research Database (Denmark)

    Sigthorsson, Oskar; Ommen, Torben Schmidt; Elmegaard, Brian

    2017-01-01

    In the entropy generation paradox, the entropy generation number, as a function of heat exchanger effectiveness, counter-intuitively approaches zero in two limits symmetrically from a single maximum. In thermoeconomic diagnosis, namely in the characteristic curve method, the exergy destruction...... to the entropy generation paradox, as a decreased heat exchanger effectiveness (as in the case of an operation anomaly in the component) can counter-intuitively result in decreased exergy destruction rate of the component. Therefore, along with an improper selection of independent variables, the heat exchanger...... increases in case of an operation anomaly in a component. The normalised exergy destruction rate as the dependent variable therefore resolves the relation of the characteristic curve method with the entropy generation paradox....

  8. Density estimation by maximum quantum entropy

    International Nuclear Information System (INIS)

    Silver, R.N.; Wallstrom, T.; Martz, H.F.

    1993-01-01

    A new Bayesian method for non-parametric density estimation is proposed, based on a mathematical analogy to quantum statistical physics. The mathematical procedure is related to maximum entropy methods for inverse problems and image reconstruction. The information divergence enforces global smoothing toward default models, convexity, positivity, extensivity and normalization. The novel feature is the replacement of classical entropy by quantum entropy, so that local smoothing is enforced by constraints on differential operators. The linear response of the estimate is proportional to the covariance. The hyperparameters are estimated by type-II maximum likelihood (evidence). The method is demonstrated on textbook data sets

  9. Miniaturized GPS/MEMS IMU integrated board

    Science.gov (United States)

    Lin, Ching-Fang (Inventor)

    2012-01-01

    This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.

  10. Entropy of charged dilaton-axion black hole

    International Nuclear Information System (INIS)

    Ghosh, Tanwi; SenGupta, Soumitra

    2008-01-01

    Using the brick wall method, the entropy of the charged dilaton-axion black hole is determined for both asymptotically flat and nonflat cases. The entropy turns out to be proportional to the horizon area of the black hole confirming the Bekenstein-Hawking area-entropy formula for black holes. The leading order logarithmic corrections to the entropy are also derived for such black holes.

  11. Going Fabless with MEMS

    Directory of Open Access Journals (Sweden)

    Bhaskar CHOUBEY

    2011-04-01

    Full Text Available The Microelectromechanical sensors are finding increasing applications in everyday life. However, each MEMS sensor is generally fabricated on its own individual process. This leads to high cost per sensor. It has been suggested the MEMS should and would follow the path of integrated circuits industry, wherein fabless firms could concentrate on design leading pure-foundries to perfect the manufacturing process. With several designs being manufactured on the same process, the installation cost of fabrication would be evenly shared. Simultaneously, multiple project wafer runs are being offered for MEMS processes to encourage design activity in universities as well as startups. This paper reviews the present state of this transition through an experience of designing and manufacturing microelectromechanical resonators on different processes.

  12. Structured synthesis of MEMS using evolutionary approaches

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Achiche, Sofiane

    2008-01-01

    In this paper, we discuss the hierarchy that is involved in a typical MEMS design and how evolutionary approaches can be used to automate the hierarchical synthesis process for MEMS. The paper first introduces the flow of a structured MEMS design process and emphasizes that system-level lumped...

  13. Three dimensional MEMS supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei

    2011-10-15

    and the specific power of 0.58 mWcm-2 at 20mVs-1 scan rate. The 3D MEMS supercapacitor fabricated in this project has the specific capacitance and the specific power of 0.029 F cm-2 and 2.2 mWcm-2 respectively at a relative large discharge rate of 5 m Acm-2. It is also found vi that the supercapacitors have the performance of broad frequency range up to 300Hz. For DRIE based 3D MEMS supercapacitor, the innovative designs were developed based on silicon micromachining process flow which includes the key processes such as thermal oxidation, RF sputtering, wet etching, DRIE, electroless plating and P Py polymerization. The optimized P Py electrode doping with Tos- performed ideal super capacitor properties in NaCl electrolyte. The single PPy electrode of the 3D MEMS supercapacitors can provide 0.128 F cm-2 specific capacitance and 1.28 mWcm-2 specific power at 20 mvs-1 scan rate. The specific capacitance of the 3D MEMS supercapacitors equals 0.056 F cm-2, and the specific power at 20 mvs-1 scan rate equals 0.56 mWcm-2. In addition, novel supercapacitors based on wafer level process are designed for flexible integration in applications such as high temperature electronics and hybrid power system for electric vehicles. Experimental work on TiO2 anodic oxidation, which enables the fabrication of the one of these designs, has been carried out. Dense TiO2 nano holes with diameters ranged from about 90 to 270 nm were obtained in 0.05 wt% HF aqueous solutions with two-step anodic oxidation method. Comparing to the published specific capacitance (about 2 mFcm-2) for microsupercapacitors [33], I have achieved much larger specific capacitance (typically 0.029 to 0.056 F cm-2) for 3D MEMS supercapacitors. The above results have been presented in 3 international conferences. Total 4 journal articles have been published, and one has been submitted. The article in the Journal of Power Source (appendix 3) has been cited 9 times after published in April 2009, and the article in

  14. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems.

    Science.gov (United States)

    Hanel, Rudolf; Thurner, Stefan; Gell-Mann, Murray

    2014-05-13

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there has been an ongoing controversy over whether the notion of the maximum entropy principle can be extended in a meaningful way to nonextensive, nonergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for nonergodic and complex statistical systems if their relative entropy can be factored into a generalized multiplicity and a constraint term. The problem of finding such a factorization reduces to finding an appropriate representation of relative entropy in a linear basis. In a particular example we show that path-dependent random processes with memory naturally require specific generalized entropies. The example is to our knowledge the first exact derivation of a generalized entropy from the microscopic properties of a path-dependent random process.

  15. Entropy Coherent and Entropy Convex Measures of Risk

    NARCIS (Netherlands)

    Laeven, R.J.A.; Stadje, M.A.

    2011-01-01

    We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. We prove that convex, entropy convex and entropy coherent measures of risk emerge as certainty equivalents under variational, homothetic and multiple priors preferences,

  16. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Electron density distribution and bonding in ZnSe and PbSe using maximum entropy method (MEM) · K S Syed Ali R Saravanan S Israel R K Rajaram · More Details Abstract Fulltext PDF. The study of electronic structure of materials and bonding is an important part of material characterization. The maximum entropy method ...

  17. Multivariate refined composite multiscale entropy analysis

    International Nuclear Information System (INIS)

    Humeau-Heurtier, Anne

    2016-01-01

    Multiscale entropy (MSE) has become a prevailing method to quantify signals complexity. MSE relies on sample entropy. However, MSE may yield imprecise complexity estimation at large scales, because sample entropy does not give precise estimation of entropy when short signals are processed. A refined composite multiscale entropy (RCMSE) has therefore recently been proposed. Nevertheless, RCMSE is for univariate signals only. The simultaneous analysis of multi-channel (multivariate) data often over-performs studies based on univariate signals. We therefore introduce an extension of RCMSE to multivariate data. Applications of multivariate RCMSE to simulated processes reveal its better performances over the standard multivariate MSE. - Highlights: • Multiscale entropy quantifies data complexity but may be inaccurate at large scale. • A refined composite multiscale entropy (RCMSE) has therefore recently been proposed. • Nevertheless, RCMSE is adapted to univariate time series only. • We herein introduce an extension of RCMSE to multivariate data. • It shows better performances than the standard multivariate multiscale entropy.

  18. Applications of Entropy in Finance: A Review

    Directory of Open Access Journals (Sweden)

    Guanqun Tong

    2013-11-01

    Full Text Available Although the concept of entropy is originated from thermodynamics, its concepts and relevant principles, especially the principles of maximum entropy and minimum cross-entropy, have been extensively applied in finance. In this paper, we review the concepts and principles of entropy, as well as their applications in the field of finance, especially in portfolio selection and asset pricing. Furthermore, we review the effects of the applications of entropy and compare them with other traditional and new methods.

  19. Spectrum unfolding in X-ray spectrometry using the maximum entropy method

    International Nuclear Information System (INIS)

    Fernandez, Jorge E.; Scot, Viviana; Di Giulio, Eugenio

    2014-01-01

    The solution of the unfolding problem is an ever-present issue in X-ray spectrometry. The maximum entropy technique solves this problem by taking advantage of some known a priori physical information and by ensuring an outcome with only positive values. This method is implemented in MAXED (MAXimum Entropy Deconvolution), a software code contained in the package UMG (Unfolding with MAXED and GRAVEL) developed at PTB and distributed by NEA Data Bank. This package contains also the code GRAVEL (used to estimate the precision of the solution). This article introduces the new code UMESTRAT (Unfolding Maximum Entropy STRATegy) which applies a semi-automatic strategy to solve the unfolding problem by using a suitable combination of MAXED and GRAVEL for applications in X-ray spectrometry. Some examples of the use of UMESTRAT are shown, demonstrating its capability to remove detector artifacts from the measured spectrum consistently with the model used for the detector response function (DRF). - Highlights: ► A new strategy to solve the unfolding problem in X-ray spectrometry is presented. ► The presented strategy uses a suitable combination of the codes MAXED and GRAVEL. ► The applied strategy provides additional information on the Detector Response Function. ► The code UMESTRAT is developed to apply this new strategy in a semi-automatic mode

  20. Use of thermal cycling to reduce adhesion of OTS coated coated MEMS cantilevers

    Science.gov (United States)

    Ali, Shaikh M.; Phinney, Leslie M.

    2003-01-01

    °Microelectromechanical systems (MEMS) have enormous potential to contribute in diverse fields such as automotive, health care, aerospace, consumer products, and biotechnology, but successful commercial applications of MEMS are still small in number. Reliability of MEMS is a major impediment to the commercialization of laboratory prototypes. Due to the multitude of MEMS applications and the numerous processing and packaging steps, MEMS are exposed to a variety of environmental conditions, making the prediction of operational reliability difficult. In this paper, we investigate the effects of operating temperature on the in-use adhesive failure of electrostatically actuated MEMS microcantilevers coated with octadecyltrichlorosilane (OTS) films. The cantilevers are subjected to repeated temperature cycles and electrostatically actuated at temperatures between 25°C and 300°C in ambient air. The experimental results indicate that temperature cycling of the OTS coated cantilevers in air reduces the sticking probability of the microcantilevers. The sticking probability of OTS coated cantilevers was highest during heating, which decreased during cooling, and was lowest during reheating. Modifications to the OTS release method to increase its yield are also discussed.

  1. Entropy coherent and entropy convex measures of risk

    NARCIS (Netherlands)

    Laeven, Roger; Stadje, M.A.

    2010-01-01

    We introduce entropy coherent and entropy convex measures of risk and prove a collection of axiomatic characterization and duality results. We show in particular that entropy coherent and entropy convex measures of risk emerge as negative certainty equivalents in (the regular and a generalized

  2. System Entropy Measurement of Stochastic Partial Differential Systems

    Directory of Open Access Journals (Sweden)

    Bor-Sen Chen

    2016-03-01

    Full Text Available System entropy describes the dispersal of a system’s energy and is an indication of the disorder of a physical system. Several system entropy measurement methods have been developed for dynamic systems. However, most real physical systems are always modeled using stochastic partial differential dynamic equations in the spatio-temporal domain. No efficient method currently exists that can calculate the system entropy of stochastic partial differential systems (SPDSs in consideration of the effects of intrinsic random fluctuation and compartment diffusion. In this study, a novel indirect measurement method is proposed for calculating of system entropy of SPDSs using a Hamilton–Jacobi integral inequality (HJII-constrained optimization method. In other words, we solve a nonlinear HJII-constrained optimization problem for measuring the system entropy of nonlinear stochastic partial differential systems (NSPDSs. To simplify the system entropy measurement of NSPDSs, the global linearization technique and finite difference scheme were employed to approximate the nonlinear stochastic spatial state space system. This allows the nonlinear HJII-constrained optimization problem for the system entropy measurement to be transformed to an equivalent linear matrix inequalities (LMIs-constrained optimization problem, which can be easily solved using the MATLAB LMI-toolbox (MATLAB R2014a, version 8.3. Finally, several examples are presented to illustrate the system entropy measurement of SPDSs.

  3. Compressibility and rarefaction effects on entropy and entropy generation in micro/nano Couette flow using DSMC

    International Nuclear Information System (INIS)

    Ejtehadi, Omid; Esfahani, Javad Abolfazli; Roohi, Ehsan

    2012-01-01

    In the present work, compressible flow of argon gas in the famous problem of Couette flow in micro/nano-scale is considered and numerically analyzed using the direct simulation Monte Carlo (DSMC) method. The effects of compressibility and rarefaction on entropy and entropy generation in terms of viscous dissipation and thermal diffusion are studied in a wide range of Mach and Knudsen numbers and the observed physics are discussed. In this regard, we computed entropy by using its kinetic theory formulation in a microscopic way while the entropy generation distribution is achieved by applying a semi-microscopic approach and thoroughly free from equilibrium assumptions. The results of our simulations demonstrated that the entropy profiles are in accordance with the temperature profiles. It is also illustrated that the increase of Mach number will result in non-uniform entropy profiles with increase in the vicinity of the central regions of the channel. Moreover, generation of entropy in all regions of the domain stages clear growth. By contrast, increasing the Knudsen number has inverse effects such as: uniform entropy profiles and a falling off in entropy generation amount throughout the channel.

  4. Minimal entropy approximation for cellular automata

    International Nuclear Information System (INIS)

    Fukś, Henryk

    2014-01-01

    We present a method for the construction of approximate orbits of measures under the action of cellular automata which is complementary to the local structure theory. The local structure theory is based on the idea of Bayesian extension, that is, construction of a probability measure consistent with given block probabilities and maximizing entropy. If instead of maximizing entropy one minimizes it, one can develop another method for the construction of approximate orbits, at the heart of which is the iteration of finite-dimensional maps, called minimal entropy maps. We present numerical evidence that the minimal entropy approximation sometimes outperforms the local structure theory in characterizing the properties of cellular automata. The density response curve for elementary CA rule 26 is used to illustrate this claim. (paper)

  5. Analysis of calculating methods for failure distribution function based on maximal entropy principle

    International Nuclear Information System (INIS)

    Guo Chunying; Lin Yuangen; Jiang Meng; Wu Changli

    2009-01-01

    The computation of invalidation distribution functions of electronic devices when exposed in gamma rays is discussed here. First, the possible devices failure distribution models are determined through the tests of statistical hypotheses using the test data. The results show that: the devices' failure distribution can obey multi-distributions when the test data is few. In order to decide the optimum failure distribution model, the maximal entropy principle is used and the elementary failure models are determined. Then, the Bootstrap estimation method is used to simulate the intervals estimation of the mean and the standard deviation. On the basis of this, the maximal entropy principle is used again and the simulated annealing method is applied to find the optimum values of the mean and the standard deviation. Accordingly, the electronic devices' optimum failure distributions are finally determined and the survival probabilities are calculated. (authors)

  6. MEMS reliability: coming of age

    Science.gov (United States)

    Douglass, Michael R.

    2008-02-01

    In today's high-volume semiconductor world, one could easily take reliability for granted. As the MOEMS/MEMS industry continues to establish itself as a viable alternative to conventional manufacturing in the macro world, reliability can be of high concern. Currently, there are several emerging market opportunities in which MOEMS/MEMS is gaining a foothold. Markets such as mobile media, consumer electronics, biomedical devices, and homeland security are all showing great interest in microfabricated products. At the same time, these markets are among the most demanding when it comes to reliability assurance. To be successful, each company developing a MOEMS/MEMS device must consider reliability on an equal footing with cost, performance and manufacturability. What can this maturing industry learn from the successful development of DLP technology, air bag accelerometers and inkjet printheads? This paper discusses some basic reliability principles which any MOEMS/MEMS device development must use. Examples from the commercially successful and highly reliable Digital Micromirror Device complement the discussion.

  7. Effective updating process of seismic fragilities using Bayesian method and information entropy

    International Nuclear Information System (INIS)

    Kato, Masaaki; Takata, Takashi; Yamaguchi, Akira

    2008-01-01

    Seismic probabilistic safety assessment (SPSA) is an effective method for evaluating overall performance of seismic safety of a plant. Seismic fragilities are estimated to quantify the seismically induced accident sequences. It is a great concern that the SPSA results involve uncertainties, a part of which comes from the uncertainty in the seismic fragility of equipment and systems. A straightforward approach to reduce the uncertainty is to perform a seismic qualification test and to reflect the results on the seismic fragility estimate. In this paper, we propose a figure-of-merit to find the most cost-effective condition of the seismic qualification tests about the acceleration level and number of components tested. Then a mathematical method to reflect the test results on the fragility update is developed. A Bayesian method is used for the fragility update procedure. Since a lognormal distribution that is used for the fragility model does not have a Bayes conjugate function, a parameterization method is proposed so that the posterior distribution expresses the characteristics of the fragility. The information entropy is used as the figure-of-merit to express importance of obtained evidence. It is found that the information entropy is strongly associated with the uncertainty of the fragility. (author)

  8. Entropy coherent and entropy convex measures of risk

    NARCIS (Netherlands)

    Laeven, R.J.A.; Stadje, M.

    2013-01-01

    We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. Entropy coherent and entropy convex measures of risk are special cases of φ-coherent and φ-convex measures of risk. Contrary to the classical use of coherent and convex

  9. Videometrics-based Detection of Vibration Linearity in MEMS Gyroscope

    Directory of Open Access Journals (Sweden)

    Yong Zhou

    2011-05-01

    Full Text Available MEMS gyroscope performs as a sort of sensor to detect angular velocity, with diverse applications in engineering including vehicle and intelligent traffic etc. A balanced vibration of driving module excited by electrostatic driving signal is the base MEMS gyroscope's performance. In order to analyze the linear property of vibration in MEMS Gyroscope, a method of computer vision measuring is applied with the help of high-speed vidicon to obtain video of linear vibration of driving module in gyroscope, under the driving voltage signal of inherent frequency and amplitude linearly increasing. By means of image processing, target identifying, and motion parameter extracting from the obtained video, vibration curve with time variation is acquired. And then, linearity of this vibration system can be analyzed by focusing on the amplitude value of vibration responding to the amplitude variation of driving voltage signal.

  10. Short-time maximum entropy method analysis of molecular dynamics simulation: Unimolecular decomposition of formic acid

    Science.gov (United States)

    Takahashi, Osamu; Nomura, Tetsuo; Tabayashi, Kiyohiko; Yamasaki, Katsuyoshi

    2008-07-01

    We performed spectral analysis by using the maximum entropy method instead of the traditional Fourier transform technique to investigate the short-time behavior in molecular systems, such as the energy transfer between vibrational modes and chemical reactions. This procedure was applied to direct ab initio molecular dynamics calculations for the decomposition of formic acid. More reactive trajectories of dehydrolation than those of decarboxylation were obtained for Z-formic acid, which was consistent with the prediction of previous theoretical and experimental studies. Short-time maximum entropy method analyses were performed for typical reactive and non-reactive trajectories. Spectrograms of a reactive trajectory were obtained; these clearly showed the reactant, transient, and product regions, especially for the dehydrolation path.

  11. MemBrain: An Easy-to-Use Online Webserver for Transmembrane Protein Structure Prediction

    Science.gov (United States)

    Yin, Xi; Yang, Jing; Xiao, Feng; Yang, Yang; Shen, Hong-Bin

    2018-03-01

    Membrane proteins are an important kind of proteins embedded in the membranes of cells and play crucial roles in living organisms, such as ion channels, transporters, receptors. Because it is difficult to determinate the membrane protein's structure by wet-lab experiments, accurate and fast amino acid sequence-based computational methods are highly desired. In this paper, we report an online prediction tool called MemBrain, whose input is the amino acid sequence. MemBrain consists of specialized modules for predicting transmembrane helices, residue-residue contacts and relative accessible surface area of α-helical membrane proteins. MemBrain achieves a prediction accuracy of 97.9% of A TMH, 87.1% of A P, 3.2 ± 3.0 of N-score, 3.1 ± 2.8 of C-score. MemBrain-Contact obtains 62%/64.1% prediction accuracy on training and independent dataset on top L/5 contact prediction, respectively. And MemBrain-Rasa achieves Pearson correlation coefficient of 0.733 and its mean absolute error of 13.593. These prediction results provide valuable hints for revealing the structure and function of membrane proteins. MemBrain web server is free for academic use and available at www.csbio.sjtu.edu.cn/bioinf/MemBrain/. [Figure not available: see fulltext.

  12. Evaluation index system of steel industry sustainable development based on entropy method and topsis method

    Science.gov (United States)

    Ronglian, Yuan; Mingye, Ai; Qiaona, Jia; Yuxuan, Liu

    2018-03-01

    Sustainable development is the only way for the development of human society. As an important part of the national economy, the steel industry is an energy-intensive industry and needs to go further for sustainable development. In this paper, we use entropy method and Topsis method to evaluate the development of China’s steel industry during the “12th Five-Year Plan” from four aspects: resource utilization efficiency, main energy and material consumption, pollution status and resource reuse rate. And we also put forward some suggestions for the development of China’s steel industry.

  13. Electroplating of low stress permalloy for MEMS

    International Nuclear Information System (INIS)

    Zhang Yonghua; Ding Guifu; Cai Yuli; Wang Hong; Cai Bingchu

    2006-01-01

    With the wafer-bending method and spectrophotometry, the internal stress in electroplated Ni-Fe alloy for MEMS has been investigated as a function of bath concentration. This investigation demonstrated that low concentration plating solution is useful for the decrease of the residual stress in the electrodeposits, and the stress could further decrease with an increase of saccharin additive content. And the change of stress from tensile to compressive was not observed with the increase of the additive content in plating path. The low stress permalloy (Ni 81 Fe 19 ) was reached in our experimental conditions. A bistable electromagnetic RF MEMS switch with deformation-free bilayer cantilever beam was fabricated successfully by electroplated permalloy

  14. Electron density distribution and bonding in ZnSe and PbSe using ...

    Indian Academy of Sciences (India)

    Unknown

    structural refinement using JANA 2000, and then the re- fined structure factors have been utilized for MEM re- finements to elucidate the ... the appropriate methods in which the concept of entropy is introduced to handle the uncertainty properly. The principle of MEM is to obtain an electron density distri- bution, which is ...

  15. Research on the attitude of small UAV based on MEMS devices

    Science.gov (United States)

    Shi, Xiaojie; Lu, Libin; Jin, Guodong; Tan, Lining

    2017-05-01

    This paper mainly introduces the research principle and implementation method of the small UAV navigation attitude system based on MEMS devices. The Gauss - Newton method based on least squares is used to calibrate the MEMS accelerometer and gyroscope for calibration. Improve the accuracy of the attitude by using the modified complementary filtering to correct the attitude angle error. The experimental data show that the design of the attitude and attitude system in this paper to meet the requirements of small UAV attitude accuracy to achieve a small, low cost.

  16. Novel SU-8 based vacuum wafer-level packaging for MEMS devices

    DEFF Research Database (Denmark)

    Murillo, Gonzalo; Davis, Zachary James; Keller, Stephan Urs

    2010-01-01

    This work presents a simple and low-cost SU-8 based wafer-level vacuum packaging method which is CMOS and MEMS compatible. Different approaches have been investigated by taking advantage of the properties of SU-8, such as chemical resistance, optical transparence, mechanical reliability and versa......This work presents a simple and low-cost SU-8 based wafer-level vacuum packaging method which is CMOS and MEMS compatible. Different approaches have been investigated by taking advantage of the properties of SU-8, such as chemical resistance, optical transparence, mechanical reliability...

  17. Optimization and simulation of MEMS rectilinear ion trap

    Directory of Open Access Journals (Sweden)

    Huang Gang

    2015-04-01

    Full Text Available In this paper, the design of a MEMS rectilinear ion trap was optimized under simulated conditions. The size range of the MEMS rectilinear ion trap’s electrodes studied in this paper is measured at micron scale. SIMION software was used to simulate the MEMS rectilinear ion trap with different sizes and different radio-frequency signals. The ion-trapping efficiencies of the ion trap under these different simulation conditions were obtained. The ion-trapping efficiencies were compared to determine the performance of the MEMS rectilinear ion trap in different conditions and to find the optimum conditions. The simulation results show that for the ion trap at micron scale or smaller, the optimized length–width ratio was 0.8, and a higher frequency of radio-frequency signal is necessary to obtain a higher ion-trapping efficiency. These results have a guiding role in the process of developing MEMS rectilinear ion traps, and great application prospects in the research fields of the MEMS rectilinear ion trap and the MEMS mass spectrometer.

  18. CFD Prediction of Airfoil Drag in Viscous Flow Using the Entropy Generation Method

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2018-01-01

    Full Text Available A new aerodynamic force of drag prediction approach was developed to compute the airfoil drag via entropy generation rate in the flow field. According to the momentum balance, entropy generation and its relationship to drag were derived for viscous flow. Model equations for the calculation of the local entropy generation in turbulent flows were presented by extending the RANS procedure to the entropy balance equation. The accuracy of algorithm and programs was assessed by simulating the pressure coefficient distribution and dragging coefficient of different airfoils under different Reynolds number at different attack angle. Numerical data shows that the total entropy generation rate in the flow field and the drag coefficient of the airfoil can be related by linear equation, which indicates that the total drag could be resolved into entropy generation based on its physical mechanism of energy loss.

  19. Progress in Preparation and Research of High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    CHEN Yong-xing

    2017-11-01

    Full Text Available The current high entropy alloys' studies are most in block, powder, coating, film and other areas. There are few studies of high entropy alloys in other areas and they are lack of unified classification. According to the current high entropy alloys' research situation, The paper has focused on the classification on all kinds of high entropy alloys having been researched, introduced the selecting principle of elements, summarized the preparation methods, reviewed the research institutions, research methods and research contents of high entropy alloys, prospected the application prospect of high entropy alloys, put forward a series of scientific problems of high entropy alloys, including less research on mechanism, incomplete performance research, unsystematic thermal stability study, preparation process parameters to be optimized, lightweight high entropy alloys' design, the expansion on the research field, etc, and the solutions have been given. Those have certain guiding significance for the expansion of the application of high entropy alloys subjects in the future research direction.

  20. Thermodynamic optimization of ground heat exchangers with single U-tube by entropy generation minimization method

    International Nuclear Information System (INIS)

    Li Min; Lai, Alvin C.K.

    2013-01-01

    Highlights: ► A second-law-based analysis is performed for single U-tube ground heat exchangers. ► Two expressions for the optimal length and flow velocity are developed for GHEs. ► Empirical velocities of GHEs are large compared to thermodynamic optimum values. - Abstract: This paper investigates thermodynamic performance of borehole ground heat exchangers with a single U-tube by the entropy generation minimization method which requires information of heat transfer and fluid mechanics, in addition to thermodynamics analysis. This study first derives an expression for dimensionless entropy generation number, a function that consists of five dimensionless variables, including Reynolds number, dimensionless borehole length, scale factor of pressures, and two duty parameters of ground heat exchangers. The derivation combines a heat transfer model and a hydraulics model for borehole ground heat exchangers with the first law and the second law of thermodynamics. Next, the entropy generation number is minimized to produce two analytical expressions for the optimal length and the optimal flow velocity of ground heat exchangers. Then, this paper discusses and analyzes implications and applications of these optimization formulas with two case studies. An important finding from the case studies is that widely used empirical velocities of circulating fluid are too large to operate ground-coupled heat pump systems in a thermodynamic optimization way. This paper demonstrates that thermodynamic optimal parameters of ground heat exchangers can probably be determined by using the entropy generation minimization method.

  1. An Evolutionary Approach for Robust Layout Synthesis of MEMS

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Goodman, Erik

    2005-01-01

    The paper introduces a robust design method for layout synthesis of MEM resonators subject to inherent geometric uncertainties such as the fabrication error on the sidewall of the structure. The robust design problem is formulated as a multi-objective constrained optimisation problem after certain...... assumptions and treated with multiobjective genetic algorithm (MOGA), a special type of evolutionary computing approaches. Case study based on layout synthesis of a comb-driven MEM resonator shows that the approach proposed in this paper can lead to design results that meet the target performance and are less...

  2. A fatigue test method for Pb(Zr,Ti)O3 thin films by using MEMS-based self-sensitive piezoelectric microcantilevers

    Science.gov (United States)

    Kobayashi, T.; Maeda, R.; Itoh, T.

    2008-11-01

    In the present study, we propose a new method for the fatigue test of lead zirconate titanate (PZT) thin films for MEMS devices by using self-sensitive piezoelectric microcantilevers developed in our previous study. We have deposited PZT thin films on SOI wafers and fabricated the microcantilevers through the MEMS microfabrication process. In the self-sensitive piezoelectric microcantilevers, the PZT thin films are separated in order to act as an actuator and a sensor. The fatigue characteristic of the PZT thin films can be evaluated by measuring the output voltage of the sensor as a function of time. When a sine wave of 20 Vpp and a dc bias of 10 V were applied to the PZT thin films for an actuator, the output voltage of the sensor fell down after 107 fatigue cycles. We have also investigated the influence of amplitude of the actuation sine wave and dc bias on the fatigue of the PZT thin films by using the proposed fatigue test method.

  3. A fatigue test method for Pb(Zr,Ti)O3 thin films by using MEMS-based self-sensitive piezoelectric microcantilevers

    International Nuclear Information System (INIS)

    Kobayashi, T; Maeda, R; Itoh, T

    2008-01-01

    In the present study, we propose a new method for the fatigue test of lead zirconate titanate (PZT) thin films for MEMS devices by using self-sensitive piezoelectric microcantilevers developed in our previous study. We have deposited PZT thin films on SOI wafers and fabricated the microcantilevers through the MEMS microfabrication process. In the self-sensitive piezoelectric microcantilevers, the PZT thin films are separated in order to act as an actuator and a sensor. The fatigue characteristic of the PZT thin films can be evaluated by measuring the output voltage of the sensor as a function of time. When a sine wave of 20 V pp and a dc bias of 10 V were applied to the PZT thin films for an actuator, the output voltage of the sensor fell down after 10 7 fatigue cycles. We have also investigated the influence of amplitude of the actuation sine wave and dc bias on the fatigue of the PZT thin films by using the proposed fatigue test method

  4. Prediction Model of Collapse Risk Based on Information Entropy and Distance Discriminant Analysis Method

    Directory of Open Access Journals (Sweden)

    Hujun He

    2017-01-01

    Full Text Available The prediction and risk classification of collapse is an important issue in the process of highway construction in mountainous regions. Based on the principles of information entropy and Mahalanobis distance discriminant analysis, we have produced a collapse hazard prediction model. We used the entropy measure method to reduce the influence indexes of the collapse activity and extracted the nine main indexes affecting collapse activity as the discriminant factors of the distance discriminant analysis model (i.e., slope shape, aspect, gradient, and height, along with exposure of the structural face, stratum lithology, relationship between weakness face and free face, vegetation cover rate, and degree of rock weathering. We employ postearthquake collapse data in relation to construction of the Yingxiu-Wolong highway, Hanchuan County, China, as training samples for analysis. The results were analyzed using the back substitution estimation method, showing high accuracy and no errors, and were the same as the prediction result of uncertainty measure. Results show that the classification model based on information entropy and distance discriminant analysis achieves the purpose of index optimization and has excellent performance, high prediction accuracy, and a zero false-positive rate. The model can be used as a tool for future evaluation of collapse risk.

  5. Applications of quantum entropy to statistics

    International Nuclear Information System (INIS)

    Silver, R.N.; Martz, H.F.

    1994-01-01

    This paper develops two generalizations of the maximum entropy (ME) principle. First, Shannon classical entropy is replaced by von Neumann quantum entropy to yield a broader class of information divergences (or penalty functions) for statistics applications. Negative relative quantum entropy enforces convexity, positivity, non-local extensivity and prior correlations such as smoothness. This enables the extension of ME methods from their traditional domain of ill-posed in-verse problems to new applications such as non-parametric density estimation. Second, given a choice of information divergence, a combination of ME and Bayes rule is used to assign both prior and posterior probabilities. Hyperparameters are interpreted as Lagrange multipliers enforcing constraints. Conservation principles are proposed to act statistical regularization and other hyperparameters, such as conservation of information and smoothness. ME provides an alternative to heirarchical Bayes methods

  6. The application of entropy weight topsis method for optimal choice in low radiological decorative building materials

    International Nuclear Information System (INIS)

    Feng Guangwen; Hu Youhua; Liu Qian

    2010-01-01

    In this paper, the principle of TOPSIS method was introduced and applied to sorting the given indexes of glazed brick and granite respectively in different areas' decorative building materials in order to selecting the optimal low radiological decorative building materials. First, the entropy weight TOPSIS method was used for data processing about the sample numbers and radio nuclides content, and then different weights were given to different indexes. Finally, by using the SAS software for data analysis and sorting, we obtained that the optimal low radiological decorative building materials were Sichuan glazed brick and Henan granite. Through the results, it could be seen that the application of entropy weight TOPSIS method in selecting low radiological decorative building materials was feasible, and it will also provide the method reference. (authors)

  7. Optimized Kernel Entropy Components.

    Science.gov (United States)

    Izquierdo-Verdiguier, Emma; Laparra, Valero; Jenssen, Robert; Gomez-Chova, Luis; Camps-Valls, Gustau

    2017-06-01

    This brief addresses two main issues of the standard kernel entropy component analysis (KECA) algorithm: the optimization of the kernel decomposition and the optimization of the Gaussian kernel parameter. KECA roughly reduces to a sorting of the importance of kernel eigenvectors by entropy instead of variance, as in the kernel principal components analysis. In this brief, we propose an extension of the KECA method, named optimized KECA (OKECA), that directly extracts the optimal features retaining most of the data entropy by means of compacting the information in very few features (often in just one or two). The proposed method produces features which have higher expressive power. In particular, it is based on the independent component analysis framework, and introduces an extra rotation to the eigen decomposition, which is optimized via gradient-ascent search. This maximum entropy preservation suggests that OKECA features are more efficient than KECA features for density estimation. In addition, a critical issue in both the methods is the selection of the kernel parameter, since it critically affects the resulting performance. Here, we analyze the most common kernel length-scale selection criteria. The results of both the methods are illustrated in different synthetic and real problems. Results show that OKECA returns projections with more expressive power than KECA, the most successful rule for estimating the kernel parameter is based on maximum likelihood, and OKECA is more robust to the selection of the length-scale parameter in kernel density estimation.

  8. Using MEMS Capacitive Switches in Tunable RF Amplifiers

    Directory of Open Access Journals (Sweden)

    Danson John

    2006-01-01

    Full Text Available A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA operating at GHz and GHz, and a tunable power amplifier (PA at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB noise figure. MEMS switches are used to implement a variable matching network that allows the PA to realize up to 37% PAE improvement at low input powers.

  9. MEMS-based transmission lines for microwave applications

    Science.gov (United States)

    Wu, Qun; Fu, Jiahui; Gu, Xuemai; Shi, Huajuan; Lee, Jongchul

    2003-04-01

    This paper mainly presents a briefly review for recent progress in MEMS-based transmission lines for use in microwave and millimeterwave range. MEMS-based transmission lines including different transmission line structure such as membrane-supported microstrip line microstrip line, coplanar microshield transmission line, LIGA micromachined planar transmission line, micromachined waveguides and coplanar waveguide are discussed. MEMS-based transmission lines are characterized by low propagation loss, wide operation frequency band, low dispersion and high quality factor, in addition, the fabrication is compatible with traditional processing of integrated circuits (IC"s). The emergence of MEMS-based transmission lines provided a solution for miniaturizing microwave system and monolithic microwave integrated circuits.

  10. Information and Entropy

    Science.gov (United States)

    Caticha, Ariel

    2007-11-01

    What is information? Is it physical? We argue that in a Bayesian theory the notion of information must be defined in terms of its effects on the beliefs of rational agents. Information is whatever constrains rational beliefs and therefore it is the force that induces us to change our minds. This problem of updating from a prior to a posterior probability distribution is tackled through an eliminative induction process that singles out the logarithmic relative entropy as the unique tool for inference. The resulting method of Maximum relative Entropy (ME), which is designed for updating from arbitrary priors given information in the form of arbitrary constraints, includes as special cases both MaxEnt (which allows arbitrary constraints) and Bayes' rule (which allows arbitrary priors). Thus, ME unifies the two themes of these workshops—the Maximum Entropy and the Bayesian methods—into a single general inference scheme that allows us to handle problems that lie beyond the reach of either of the two methods separately. I conclude with a couple of simple illustrative examples.

  11. Evaluation of MEMS-Based Wireless Accelerometer Sensors in Detecting Gear Tooth Faults in Helicopter Transmissions

    Science.gov (United States)

    Lewicki, David George; Lambert, Nicholas A.; Wagoner, Robert S.

    2015-01-01

    The diagnostics capability of micro-electro-mechanical systems (MEMS) based rotating accelerometer sensors in detecting gear tooth crack failures in helicopter main-rotor transmissions was evaluated. MEMS sensors were installed on a pre-notched OH-58C spiral-bevel pinion gear. Endurance tests were performed and the gear was run to tooth fracture failure. Results from the MEMS sensor were compared to conventional accelerometers mounted on the transmission housing. Most of the four stationary accelerometers mounted on the gear box housing and most of the CI's used gave indications of failure at the end of the test. The MEMS system performed well and lasted the entire test. All MEMS accelerometers gave an indication of failure at the end of the test. The MEMS systems performed as well, if not better, than the stationary accelerometers mounted on the gear box housing with regards to gear tooth fault detection. For both the MEMS sensors and stationary sensors, the fault detection time was not much sooner than the actual tooth fracture time. The MEMS sensor spectrum data showed large first order shaft frequency sidebands due to the measurement rotating frame of reference. The method of constructing a pseudo tach signal from periodic characteristics of the vibration data was successful in deriving a TSA signal without an actual tach and proved as an effective way to improve fault detection for the MEMS.

  12. ENTROPY FUNCTIONAL FOR CONTINUOUS SYSTEMS OF FINITE ENTROPY

    Institute of Scientific and Technical Information of China (English)

    M. Rahimi A. Riazi

    2012-01-01

    In this article,we introduce the concept of entropy functional for continuous systems on compact metric spaces,and prove some of its properties.We also extract the Kolmogorov entropy from the entropy functional.

  13. Receiver function estimated by maximum entropy deconvolution

    Institute of Scientific and Technical Information of China (English)

    吴庆举; 田小波; 张乃铃; 李卫平; 曾融生

    2003-01-01

    Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.

  14. Entropy function and universality of entropy-area relation for small black holes

    International Nuclear Information System (INIS)

    Cai Ronggen; Chen, C.-M.; Maeda, Kei-ichi; Ohta, Nobuyoshi; Pang Dawei

    2008-01-01

    We discuss the entropy-area relation for the small black holes with higher curvature corrections by using the entropy function formalism and field redefinition method. We show that the entropy S BH of the small black hole is proportional to its horizon area A. In particular, we find a universal result that S BH =A/2G, the ratio is 2 times of Bekenstein-Hawking entropy-area formula in many cases of physical interest. In four dimensions, the universal relation is always true irrespective of the coefficients of the higher-order terms if the dilaton couplings are the same, which is the case for string effective theory, while in five dimensions, the relation again holds irrespective of the overall coefficient if the higher-order corrections are in the GB combination. We also discuss how this result generalizes to known physically interesting cases with Lovelock correction terms in various dimensions, and possible implications of the universal relation.

  15. A Bayes-Maximum Entropy method for multi-sensor data fusion

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, M.

    1991-01-01

    In this paper we introduce a Bayes-Maximum Entropy formalism for multi-sensor data fusion, and present an application of this methodology to the fusion of ultrasound and visual sensor data as acquired by a mobile robot. In our approach the principle of maximum entropy is applied to the construction of priors and likelihoods from the data. Distances between ultrasound and visual points of interest in a dual representation are used to define Gibbs likelihood distributions. Both one- and two-dimensional likelihoods are presented, and cast into a form which makes explicit their dependence upon the mean. The Bayesian posterior distributions are used to test a null hypothesis, and Maximum Entropy Maps used for navigation are updated using the resulting information from the dual representation. 14 refs., 9 figs.

  16. Entropy of the Mixture of Sources and Entropy Dimension

    OpenAIRE

    Smieja, Marek; Tabor, Jacek

    2011-01-01

    We investigate the problem of the entropy of the mixture of sources. There is given an estimation of the entropy and entropy dimension of convex combination of measures. The proof is based on our alternative definition of the entropy based on measures instead of partitions.

  17. Advanced mechatronics and MEMS devices II

    CERN Document Server

    Wei, Bin

    2017-01-01

    This book introduces the state-of-the-art technologies in mechatronics, robotics, and MEMS devices in order to improve their methodologies. It provides a follow-up to "Advanced Mechatronics and MEMS Devices" (2013) with an exploration of the most up-to-date technologies and their applications, shown through examples that give readers insights and lessons learned from actual projects. Researchers on mechatronics, robotics, and MEMS as well as graduate students in mechanical engineering will find chapters on: Fundamental design and working principles on MEMS accelerometers Innovative mobile technologies Force/tactile sensors development Control schemes for reconfigurable robotic systems Inertial microfluidics Piezoelectric force sensors and dynamic calibration techniques ...And more. Authors explore applications in the areas of agriculture, biomedicine, advanced manufacturing, and space. Micro-assembly for current and future industries is also considered, as well as the design and development of micro and intel...

  18. Tribo-functionalizing Si and SU8 materials by surface modification for application in MEMS/NEMS actuator-based devices

    International Nuclear Information System (INIS)

    Singh, R A; Satyanarayana, N; Sinha, S K; Kustandi, T S

    2011-01-01

    Micro/nano-electro-mechanical-systems (MEMS/NEMS) are miniaturized devices built at micro/nanoscales. At these scales, the surface/interfacial forces are extremely strong and they adversely affect the smooth operation and the useful operating lifetimes of such devices. When these forces manifest in severe forms, they lead to material removal and thereby reduce the wear durability of the devices. In this paper, we present a simple, yet robust, two-step surface modification method to significantly enhance the tribological performance of MEMS/NEMS materials. The two-step method involves oxygen plasma treatment of polymeric films and the application of a nanolubricant, namely perfluoropolyether. We apply the two-step method to the two most important MEMS/NEMS structural materials, namely silicon and SU8 polymer. On applying surface modification to these materials, their initial coefficient of friction reduces by ∼4-7 times and the steady-state coefficient of friction reduces by ∼2.5-3.5 times. Simultaneously, the wear durability of both the materials increases by >1000 times. The two-step method is time effective as each of the steps takes the time duration of approximately 1 min. It is also cost effective as the oxygen plasma treatment is a part of the MEMS/NEMS fabrication process. The two-step method can be readily and easily integrated into MEMS/NEMS fabrication processes. It is anticipated that this method will work for any kind of structural material from which MEMS/NEMS are or can be made.

  19. Tribo-functionalizing Si and SU8 materials by surface modification for application in MEMS/NEMS actuator-based devices

    Science.gov (United States)

    Singh, R. A.; Satyanarayana, N.; Kustandi, T. S.; Sinha, S. K.

    2011-01-01

    Micro/nano-electro-mechanical-systems (MEMS/NEMS) are miniaturized devices built at micro/nanoscales. At these scales, the surface/interfacial forces are extremely strong and they adversely affect the smooth operation and the useful operating lifetimes of such devices. When these forces manifest in severe forms, they lead to material removal and thereby reduce the wear durability of the devices. In this paper, we present a simple, yet robust, two-step surface modification method to significantly enhance the tribological performance of MEMS/NEMS materials. The two-step method involves oxygen plasma treatment of polymeric films and the application of a nanolubricant, namely perfluoropolyether. We apply the two-step method to the two most important MEMS/NEMS structural materials, namely silicon and SU8 polymer. On applying surface modification to these materials, their initial coefficient of friction reduces by ~4-7 times and the steady-state coefficient of friction reduces by ~2.5-3.5 times. Simultaneously, the wear durability of both the materials increases by >1000 times. The two-step method is time effective as each of the steps takes the time duration of approximately 1 min. It is also cost effective as the oxygen plasma treatment is a part of the MEMS/NEMS fabrication process. The two-step method can be readily and easily integrated into MEMS/NEMS fabrication processes. It is anticipated that this method will work for any kind of structural material from which MEMS/NEMS are or can be made.

  20. SU-8 Based MEMS Process with Two Metal Layers using α-Si as a Sacrificial Material

    KAUST Repository

    Ramadan, Khaled S.

    2012-04-01

    Polymer based microelectromechanical systems (MEMS) micromachining is finding more interest in research and applications. This is due to its low cost and less time processing compared with silicon MEMS. SU-8 is a photo-patternable polymer that is used as a structural layer for MEMS and microfluidic devices. In addition to being processed with low cost, it is a biocompatible material with good mechanical properties. Also, amorphous silicon (α-Si) has found use as a sacrificial layer in silicon MEMS applications. α-Si can be deposited at large thicknesses for MEMS applications and also can be released in a dry method using XeF2 which can solve stiction problems related to MEMS applications. In this thesis, an SU-8 MEMS process is developed using amorphous silicon (α-Si) as a sacrificial layer. Electrostatic actuation and sensing is used in many MEMS applications. SU-8 is a dielectric material which limits its direct use in electrostatic actuation. This thesis provides a MEMS process with two conductive metal electrodes that can be used for out-of-plane electrostatic applications like MEMS switches and variable capacitors. The process provides the fabrication of dimples that can be conductive or non-conductive to facilitate more flexibility for MEMS designers. This SU-8 process can fabricate SU-8 MEMS structures of a single layer of two different thicknesses. Process parameters were tuned for two sets of thicknesses which are thin (5-10μm) and thick (130μm). Chevron bent-beam structures and different suspended beams (cantilevers and bridges) were fabricated to characterize the SU-8 process through extracting the density, Young’s Modulus and the Coefficient of Thermal Expansion (CTE) of SU-8. Also, the process was tested and used as an educational tool through which different MEMS structures were fabricated including MEMS switches, variable capacitors and thermal actuators.

  1. RF MEMS: status of the industry and roadmaps

    Science.gov (United States)

    Bouchaud, Jeremie; Wicht, Henning

    2005-01-01

    Microsystems for Radio Frequency applications, known as RF MEMS, have entered the commercialization phase in 2003. Bulk Acoustic Wave filters are already produced in series and first commercial samples of switches are available. On the other hand, reliability and packaging problems are still a major hurdle especially for switches and tunable capacitors. Will RF MEMS hold their promise to be one of the future major businesses for MEMS? The presentation will give an overview on RF MEMS applications and market players. WTC will highlight technical challenges that still have to be solved to open mass markets such as mobile telephony and WLAN. WTC will also present applications of RF MEMS and opportunities in niche markets with high added value like military and space applications. WTC will provide a regional analysis and compare R&D focus and public funding situation in North America, Europe and Asia. Finally, WTC will present an updated product roadmap market forecast for RF MEMS devices for the 2004-2008 time period.

  2. The Micronium-A Musical MEMS instrument

    NARCIS (Netherlands)

    Engelen, Johannes Bernardus Charles; de Boer, Hans L.; de Boer, Hylco; Beekman, Jethro G.; Fortgens, Laurens C.; de Graaf, Derk B.; Vocke, Sander; Abelmann, Leon

    The Micronium is a musical instrument fabricated from silicon using microelectromechanical system (MEMS) technology. It is—to the best of our knowledge—the first musical micro-instrument fabricated using MEMS technology, where the actual sound is generated by mechanical microstructures. The

  3. Financial time series analysis based on effective phase transfer entropy

    Science.gov (United States)

    Yang, Pengbo; Shang, Pengjian; Lin, Aijing

    2017-02-01

    Transfer entropy is a powerful technique which is able to quantify the impact of one dynamic system on another system. In this paper, we propose the effective phase transfer entropy method based on the transfer entropy method. We use simulated data to test the performance of this method, and the experimental results confirm that the proposed approach is capable of detecting the information transfer between the systems. We also explore the relationship between effective phase transfer entropy and some variables, such as data size, coupling strength and noise. The effective phase transfer entropy is positively correlated with the data size and the coupling strength. Even in the presence of a large amount of noise, it can detect the information transfer between systems, and it is very robust to noise. Moreover, this measure is indeed able to accurately estimate the information flow between systems compared with phase transfer entropy. In order to reflect the application of this method in practice, we apply this method to financial time series and gain new insight into the interactions between systems. It is demonstrated that the effective phase transfer entropy can be used to detect some economic fluctuations in the financial market. To summarize, the effective phase transfer entropy method is a very efficient tool to estimate the information flow between systems.

  4. Development of Dual-Axis MEMS Accelerometers for Machine Tools Vibration Monitoring

    Directory of Open Access Journals (Sweden)

    Chih-Yung Huang

    2016-07-01

    Full Text Available With the development of intelligent machine tools, monitoring the vibration by the accelerometer is an important issue. Accelerometers used for measuring vibration signals during milling processes require the characteristics of high sensitivity, high resolution, and high bandwidth. A commonly used accelerometer is the lead zirconate titanate (PZT type; however, integrating it into intelligent modules is excessively expensive and difficult. Therefore, the micro electro mechanical systems (MEMS accelerometer is an alternative with the advantages of lower price and superior integration. In the present study, we integrated two MEMS accelerometer chips into a low-pass filter and housing to develop a low-cost dual-axis accelerometer with a bandwidth of 5 kHz and a full scale range of ±50 g for measuring machine tool vibration. In addition, a platform for measuring the linearity, cross-axis sensitivity and frequency response of the MEMS accelerometer by using the back-to-back calibration method was also developed. Finally, cutting experiments with steady and chatter cutting were performed to verify the results of comparing the MEMS accelerometer with the PZT accelerometer in the time and frequency domains. The results demonstrated that the dual-axis MEMS accelerometer is suitable for monitoring the vibration of machine tools at low cost.

  5. Using MEMS Capacitive Switches in Tunable RF Amplifiers

    OpenAIRE

    Danson John; Plett Calvin; Tait Niall

    2006-01-01

    A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA) operating at GHz and GHz, and a tunable power amplifier (PA) at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB no...

  6. Entropy for Mechanically Vibrating Systems

    Science.gov (United States)

    Tufano, Dante

    , which demonstrates the applicability of entropy-based approaches to real-world systems. Three systems are considered to demonstrate these findings: 1) a rod end-coupled to a simple oscillator, 2) two end-coupled rods, and 3) two end-coupled beams. The aforementioned work utilizes the weak coupling assumption to determine the entropy of composite systems. Following this discussion, a direct method of finding entropy is developed which does not rely on this limiting assumption. The resulting entropy provides a useful benchmark for evaluating the accuracy of the weak coupling approach, and is validated using systems of coupled oscillators. The later chapters of this work discuss Khinchin's entropy as applied to nonlinear and nonconservative systems, respectively. The discussion of entropy for nonlinear systems is motivated by the desire to expand the applicability of SEA techniques beyond the linear regime. The discussion of nonconservative systems is also crucial, since real-world systems interact with their environment, and it is necessary to confirm the validity of an entropy approach for systems that are relevant in the context of SEA. Having developed a mathematical framework for determining entropy under a number of previously unexplored cases, the relationship between thermodynamics and statistical vibroacoustics can be better understood. Specifically, vibroacoustic temperatures can be obtained for systems that are not necessarily linear or weakly coupled. In this way, entropy provides insight into how the power flow proportionality of statistical energy analysis (SEA) can be applied to a broader class of vibroacoustic systems. As such, entropy is a useful tool for both justifying and expanding the foundational results of SEA.

  7. Structure of incommensurate ammonium tetrafluoroberyllate studied by structure refinements and the maximum entropy method

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; Amami, M.; van Smaalen, S.

    2004-01-01

    Roč. 60, - (2004), s. 127-137 ISSN 0108-7681 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : incommensurate modulation * superspace * maximum entropy method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.418, year: 2004

  8. Symplectic entropy

    International Nuclear Information System (INIS)

    De Nicola, Sergio; Fedele, Renato; Man'ko, Margarita A; Man'ko, Vladimir I

    2007-01-01

    The tomographic-probability description of quantum states is reviewed. The symplectic tomography of quantum states with continuous variables is studied. The symplectic entropy of the states with continuous variables is discussed and its relation to Shannon entropy and information is elucidated. The known entropic uncertainty relations of the probability distribution in position and momentum of a particle are extended and new uncertainty relations for symplectic entropy are obtained. The partial case of symplectic entropy, which is optical entropy of quantum states, is considered. The entropy associated to optical tomogram is shown to satisfy the new entropic uncertainty relation. The example of Gaussian states of harmonic oscillator is studied and the entropic uncertainty relations for optical tomograms of the Gaussian state are shown to minimize the uncertainty relation

  9. A review of vibration-based MEMS piezoelectric energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Saadon, Salem; Sidek, Othman [Collaborative Microelectronic Design Excellence Center (CEDEC), School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

    2011-01-15

    The simplicity associated with the piezoelectric micro-generators makes it very attractive for MEMS applications, especially for remote systems. In this paper we reviewed the work carried out by researchers during the last three years. The improvements in experimental results obtained in the vibration-based MEMS piezoelectric energy harvesters show very good scope for MEMS piezoelectric harvesters in the field of power MEMS in the near future. (author)

  10. Parametric optimization of CNC end milling using entropy ...

    African Journals Online (AJOL)

    Parametric optimization of CNC end milling using entropy measurement technique combined with grey-Taguchi method. ... International Journal of Engineering, Science and Technology ... Keywords: CNC end milling, surface finish, material removal rate (MRR), entropy measurement technique, Taguchi method ...

  11. Generalized phase retrieval algorithm based on information measures

    OpenAIRE

    Shioya, Hiroyuki; Gohara, Kazutoshi

    2006-01-01

    An iterative phase retrieval algorithm based on the maximum entropy method (MEM) is presented. Introducing a new generalized information measure, we derive a novel class of algorithms which includes the conventionally used error reduction algorithm and a MEM-type iterative algorithm which is presented for the first time. These different phase retrieval methods are unified on the basis of the framework of information measures used in information theory.

  12. Entropy Based Test Point Evaluation and Selection Method for Analog Circuit Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    2014-01-01

    Full Text Available By simplifying tolerance problem and treating faulty voltages on different test points as independent variables, integer-coded table technique is proposed to simplify the test point selection process. Usually, simplifying tolerance problem may induce a wrong solution while the independence assumption will result in over conservative result. To address these problems, the tolerance problem is thoroughly considered in this paper, and dependency relationship between different test points is considered at the same time. A heuristic graph search method is proposed to facilitate the test point selection process. First, the information theoretic concept of entropy is used to evaluate the optimality of test point. The entropy is calculated by using the ambiguous sets and faulty voltage distribution, determined by component tolerance. Second, the selected optimal test point is used to expand current graph node by using dependence relationship between the test point and graph node. Simulated results indicate that the proposed method more accurately finds the optimal set of test points than other methods; therefore, it is a good solution to minimize the size of the test point set. To simplify and clarify the proposed method, only catastrophic and some specific parametric faults are discussed in this paper.

  13. Autonomous entropy-based intelligent experimental design

    Science.gov (United States)

    Malakar, Nabin Kumar

    2011-07-01

    The aim of this thesis is to explore the application of probability and information theory in experimental design, and to do so in a way that combines what we know about inference and inquiry in a comprehensive and consistent manner. Present day scientific frontiers involve data collection at an ever-increasing rate. This requires that we find a way to collect the most relevant data in an automated fashion. By following the logic of the scientific method, we couple an inference engine with an inquiry engine to automate the iterative process of scientific learning. The inference engine involves Bayesian machine learning techniques to estimate model parameters based upon both prior information and previously collected data, while the inquiry engine implements data-driven exploration. By choosing an experiment whose distribution of expected results has the maximum entropy, the inquiry engine selects the experiment that maximizes the expected information gain. The coupled inference and inquiry engines constitute an autonomous learning method for scientific exploration. We apply it to a robotic arm to demonstrate the efficacy of the method. Optimizing inquiry involves searching for an experiment that promises, on average, to be maximally informative. If the set of potential experiments is described by many parameters, the search involves a high-dimensional entropy space. In such cases, a brute force search method will be slow and computationally expensive. We develop an entropy-based search algorithm, called nested entropy sampling, to select the most informative experiment. This helps to reduce the number of computations necessary to find the optimal experiment. We also extended the method of maximizing entropy, and developed a method of maximizing joint entropy so that it could be used as a principle of collaboration between two robots. This is a major achievement of this thesis, as it allows the information-based collaboration between two robotic units towards a same

  14. Surface chemical modification for exceptional wear life of MEMS materials

    Directory of Open Access Journals (Sweden)

    R. Arvind Singh

    2011-12-01

    Full Text Available Micro-Electro-Mechanical-Systems (MEMS are built at micro/nano-scales. At these scales, the interfacial forces are extremely strong. These forces adversely affect the smooth operation and cause wear resulting in the drastic reduction in wear life (useful operating lifetime of actuator-based devices. In this paper, we present a surface chemical modification method that reduces friction and significantly extends the wear life of the two most popular MEMS structural materials namely, silicon and SU-8 polymer. The method includes surface chemical treatment using ethanolamine-sodium phosphate buffer, followed by coating of perfluoropolyether (PFPE nanolubricant on (i silicon coated with SU-8 thin films (500 nm and (ii MEMS process treated SU-8 thick films (50 μm. After the surface chemical modification, it was observed that the steady-state coefficient of friction of the materials reduced by 4 to 5 times and simultaneously their wear durability increased by more than three orders of magnitude (> 1000 times. The significant reduction in the friction coefficients is due to the lubrication effect of PFPE nanolubricant, while the exceptional increase in their wear life is attributed to the bonding between the -OH functional group of ethanolamine treated SU-8 thin/thick films and the -OH functional group of PFPE. The surface chemical modification method acts as a common route to enhance the performance of both silicon and SU-8 polymer. It is time-effective (process time ≤ 11 min, cost-effective and can be readily integrated into MEMS fabrication/assembly processes. It can also work for any kind of structural material from which the miniaturized devices are/can be made.

  15. The generalized F constraint in the maximum-entropy method - a study on simulated data

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; van Smaalen, S.

    2002-01-01

    Roč. 58, - (2002), s. 559-567 ISSN 0108-7673 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : maximum-entropy method * electron density * oxalic acid Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.417, year: 2002

  16. System-Level Modelling and Simulation of MEMS-Based Sensors

    DEFF Research Database (Denmark)

    Virk, Kashif M.; Madsen, Jan; Shafique, Mohammad

    2005-01-01

    The growing complexity of MEMS devices and their increased used in embedded systems (e.g., wireless integrated sensor networks) demands a disciplined aproach for MEMS design as well as the development of techniques for system-level modeling of these devices so that a seamless integration with the......The growing complexity of MEMS devices and their increased used in embedded systems (e.g., wireless integrated sensor networks) demands a disciplined aproach for MEMS design as well as the development of techniques for system-level modeling of these devices so that a seamless integration...... with the existing embedded system design methodologies is possible. In this paper, we present a MEMS design methodology that uses VHDL-AMS based system-level model of a MEMS device as a starting point and combines the top-down and bottom-up design approaches for design, verification, and optimization...

  17. Lattice Field Theory with the Sign Problem and the Maximum Entropy Method

    Directory of Open Access Journals (Sweden)

    Masahiro Imachi

    2007-02-01

    Full Text Available Although numerical simulation in lattice field theory is one of the most effective tools to study non-perturbative properties of field theories, it faces serious obstacles coming from the sign problem in some theories such as finite density QCD and lattice field theory with the θ term. We reconsider this problem from the point of view of the maximum entropy method.

  18. A review: aluminum nitride MEMS contour-mode resonator

    Science.gov (United States)

    Yunhong, Hou; Meng, Zhang; Guowei, Han; Chaowei, Si; Yongmei, Zhao; Jin, Ning

    2016-10-01

    Over the past several decades, the technology of micro-electromechanical system (MEMS) has advanced. A clear need of miniaturization and integration of electronics components has had new solutions for the next generation of wireless communications. The aluminum nitride (AlN) MEMS contour-mode resonator (CMR) has emerged and become promising and competitive due to the advantages of the small size, high quality factor and frequency, low resistance, compatibility with integrated circuit (IC) technology, and the ability of integrating multi-frequency devices on a single chip. In this article, a comprehensive review of AlN MEMS CMR technology will be presented, including its basic working principle, main structures, fabrication processes, and methods of performance optimization. Among these, the deposition and etching process of the AlN film will be specially emphasized and recent advances in various performance optimization methods of the CMR will be given through specific examples which are mainly focused on temperature compensation and reducing anchor losses. This review will conclude with an assessment of the challenges and future trends of the CMR. Project supported by National Natural Science Foundation (Nos. 61274001, 61234007, 61504130), the Nurturing and Development Special Projects of Beijing Science and Technology Innovation Base's Financial Support (No. Z131103002813070), and the National Defense Science and Technology Innovation Fund of CAS (No. CXJJ-14-M32).

  19. Another Method of Building 2D Entropy to Realize Automatic Segmentation

    International Nuclear Information System (INIS)

    Zhang, Y F; Zhang, Y

    2006-01-01

    2D entropy formed during the process of building 2D histogram can realize automatic segmentation. Traditional method utilizes central pixel grey value and the others or all of pixels grey mean value in 4-neighbor to build 2D histogram. In fact, the change of the greyscale value between two ''invariable position vectors'' cannot represent the total characteristics among neighbour pixels very well. A new method is proposed which makes use of minimum grey value in the 4-neighbor and of maximum grey value in the 3x3 neighbour except pixels of the 4-neighbor. New method and traditional one are used in contrast to realize image automatic segmentation. The experimental results of the classical image prove the new method is effective

  20. Modeling of biaxial gimbal-less MEMS scanning mirrors

    Science.gov (United States)

    von Wantoch, Thomas; Gu-Stoppel, Shanshan; Senger, Frank; Mallas, Christian; Hofmann, Ulrich; Meurer, Thomas; Benecke, Wolfgang

    2016-03-01

    One- and two-dimensional MEMS scanning mirrors for resonant or quasi-stationary beam deflection are primarily known as tiny micromirror devices with aperture sizes up to a few Millimeters and usually address low power applications in high volume markets, e.g. laser beam scanning pico-projectors or gesture recognition systems. In contrast, recently reported vacuum packaged MEMS scanners feature mirror diameters up to 20 mm and integrated high-reflectivity dielectric coatings. These mirrors enable MEMS based scanning for applications that require large apertures due to optical constraints like 3D sensing or microscopy as well as for high power laser applications like laser phosphor displays, automotive lighting and displays, 3D printing and general laser material processing. This work presents modelling, control design and experimental characterization of gimbal-less MEMS mirrors with large aperture size. As an example a resonant biaxial Quadpod scanner with 7 mm mirror diameter and four integrated PZT (lead zirconate titanate) actuators is analyzed. The finite element method (FEM) model developed and computed in COMSOL Multiphysics is used for calculating the eigenmodes of the mirror as well as for extracting a high order (n system inputs and scanner displacement as system output. By applying model order reduction techniques using MATLABR a compact state space system approximation of order n = 6 is computed. Based on this reduced order model feedforward control inputs for different, properly chosen scanner displacement trajectories are derived and tested using the original FEM model as well as the micromirror.

  1. A Roller Bearing Fault Diagnosis Method Based on LCD Energy Entropy and ACROA-SVM

    Directory of Open Access Journals (Sweden)

    HungLinh Ao

    2014-01-01

    Full Text Available This study investigates a novel method for roller bearing fault diagnosis based on local characteristic-scale decomposition (LCD energy entropy, together with a support vector machine designed using an Artificial Chemical Reaction Optimisation Algorithm, referred to as an ACROA-SVM. First, the original acceleration vibration signals are decomposed into intrinsic scale components (ISCs. Second, the concept of LCD energy entropy is introduced. Third, the energy features extracted from a number of ISCs that contain the most dominant fault information serve as input vectors for the support vector machine classifier. Finally, the ACROA-SVM classifier is proposed to recognize the faulty roller bearing pattern. The analysis of roller bearing signals with inner-race and outer-race faults shows that the diagnostic approach based on the ACROA-SVM and using LCD to extract the energy levels of the various frequency bands as features can identify roller bearing fault patterns accurately and effectively. The proposed method is superior to approaches based on Empirical Mode Decomposition method and requires less time.

  2. Entanglement entropy after selective measurements in quantum chains

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Khadijeh [Department of Physics, Georgetown University,37th and O Sts. NW, Washington, DC 20057 (United States); Rajabpour, M.A. [Instituto de Física, Universidade Federal Fluminense,Av. Gal. Milton Tavares de Souza s/n, Gragoatá, 24210-346, Niterói, RJ (Brazil)

    2016-12-22

    We study bipartite post measurement entanglement entropy after selective measurements in quantum chains. We first study the quantity for the critical systems that can be described by conformal field theories. We find a connection between post measurement entanglement entropy and the Casimir energy of floating objects. Then we provide formulas for the post measurement entanglement entropy for open and finite temperature systems. We also comment on the Affleck-Ludwig boundary entropy in the context of the post measurement entanglement entropy. Finally, we also provide some formulas regarding modular hamiltonians and entanglement spectrum in the after measurement systems. After through discussion regarding CFT systems we also provide some predictions regarding massive field theories. We then discuss a generic method to calculate the post measurement entanglement entropy in the free fermion systems. Using the method we study the post measurement entanglement entropy in the XY spin chain. We check numerically the CFT and the massive field theory results in the transverse field Ising chain and the XX model. In particular, we study the post meaurement entanglement entropy in the infinite, periodic and open critical transverse field Ising chain and the critical XX model. The effect of the temperature and the gap is also discussed in these models.

  3. Entanglement entropy after selective measurements in quantum chains

    International Nuclear Information System (INIS)

    Najafi, Khadijeh; Rajabpour, M.A.

    2016-01-01

    We study bipartite post measurement entanglement entropy after selective measurements in quantum chains. We first study the quantity for the critical systems that can be described by conformal field theories. We find a connection between post measurement entanglement entropy and the Casimir energy of floating objects. Then we provide formulas for the post measurement entanglement entropy for open and finite temperature systems. We also comment on the Affleck-Ludwig boundary entropy in the context of the post measurement entanglement entropy. Finally, we also provide some formulas regarding modular hamiltonians and entanglement spectrum in the after measurement systems. After through discussion regarding CFT systems we also provide some predictions regarding massive field theories. We then discuss a generic method to calculate the post measurement entanglement entropy in the free fermion systems. Using the method we study the post measurement entanglement entropy in the XY spin chain. We check numerically the CFT and the massive field theory results in the transverse field Ising chain and the XX model. In particular, we study the post meaurement entanglement entropy in the infinite, periodic and open critical transverse field Ising chain and the critical XX model. The effect of the temperature and the gap is also discussed in these models.

  4. Quantum Statistical Entropy of Five-Dimensional Black Hole

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ren; WU Yue-Qin; ZHANG Sheng-Li

    2006-01-01

    The generalized uncertainty relation is introduced to calculate quantum statistic entropy of a black hole.By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of the five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is not the divergent logarithmic term as in the original brick-wall method. And it is obtained that the quantum statistic entropy corresponding to black hole horizon is proportional to the area of the horizon. Further it is shown that the entropy of black hole is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. It makes people further understand the quantum statistic entropy.

  5. Quantum Statistical Entropy of Five-Dimensional Black Hole

    International Nuclear Information System (INIS)

    Zhao Ren; Zhang Shengli; Wu Yueqin

    2006-01-01

    The generalized uncertainty relation is introduced to calculate quantum statistic entropy of a black hole. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of the five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is not the divergent logarithmic term as in the original brick-wall method. And it is obtained that the quantum statistic entropy corresponding to black hole horizon is proportional to the area of the horizon. Further it is shown that the entropy of black hole is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. It makes people further understand the quantum statistic entropy.

  6. Entropy equilibrium equation and dynamic entropy production in environment liquid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The entropy equilibrium equation is the basis of the nonequilibrium state thermodynamics. But the internal energy implies the kinetic energy of the fluid micelle relative to mass center in the classical entropy equilibrium equation at present. This internal energy is not the mean kinetic energy of molecular movement in thermodynamics. Here a modified entropy equilibrium equation is deduced, based on the concept that the internal energy is just the mean kinetic energy of the molecular movement. A dynamic entropy production is introduced into the entropy equilibrium equation to describe the dynamic process distinctly. This modified entropy equilibrium equation can describe not only the entropy variation of the irreversible processes but also the reversible processes in a thermodynamic system. It is more reasonable and suitable for wider applications.

  7. A new entropy based method for computing software structural complexity

    International Nuclear Information System (INIS)

    Roca, Jose L.

    2002-01-01

    In this paper a new methodology for the evaluation of software structural complexity is described. It is based on the entropy evaluation of the random uniform response function associated with the so called software characteristic function SCF. The behavior of the SCF with the different software structures and their relationship with the number of inherent errors is investigated. It is also investigated how the entropy concept can be used to evaluate the complexity of a software structure considering the SCF as a canonical representation of the graph associated with the control flow diagram. The functions, parameters and algorithms that allow to carry out this evaluation are also introduced. After this analytic phase follows the experimental phase, verifying the consistency of the proposed metric and their boundary conditions. The conclusion is that the degree of software structural complexity can be measured as the entropy of the random uniform response function of the SCF. That entropy is in direct relationship with the number of inherent software errors and it implies a basic hazard failure rate for it, so that a minimum structure assures a certain stability and maturity of the program. This metric can be used, either to evaluate the product or the process of software development, as development tool or for monitoring the stability and the quality of the final product. (author)

  8. A New Feature Extraction Method Based on EEMD and Multi-Scale Fuzzy Entropy for Motor Bearing

    Directory of Open Access Journals (Sweden)

    Huimin Zhao

    2016-12-01

    Full Text Available Feature extraction is one of the most important, pivotal, and difficult problems in mechanical fault diagnosis, which directly relates to the accuracy of fault diagnosis and the reliability of early fault prediction. Therefore, a new fault feature extraction method, called the EDOMFE method based on integrating ensemble empirical mode decomposition (EEMD, mode selection, and multi-scale fuzzy entropy is proposed to accurately diagnose fault in this paper. The EEMD method is used to decompose the vibration signal into a series of intrinsic mode functions (IMFs with a different physical significance. The correlation coefficient analysis method is used to calculate and determine three improved IMFs, which are close to the original signal. The multi-scale fuzzy entropy with the ability of effective distinguishing the complexity of different signals is used to calculate the entropy values of the selected three IMFs in order to form a feature vector with the complexity measure, which is regarded as the inputs of the support vector machine (SVM model for training and constructing a SVM classifier (EOMSMFD based on EDOMFE and SVM for fulfilling fault pattern recognition. Finally, the effectiveness of the proposed method is validated by real bearing vibration signals of the motor with different loads and fault severities. The experiment results show that the proposed EDOMFE method can effectively extract fault features from the vibration signal and that the proposed EOMSMFD method can accurately diagnose the fault types and fault severities for the inner race fault, the outer race fault, and rolling element fault of the motor bearing. Therefore, the proposed method provides a new fault diagnosis technology for rotating machinery.

  9. Packaging of MEMS/MOEMS and nanodevices: reliability, testing, and characterization aspects

    Science.gov (United States)

    Tekin, Tolga; Ngo, Ha-Duong; Wittler, Olaf; Bouhlal, Bouchaib; Lang, Klaus-Dieter

    2011-02-01

    The last decade witnessed an explosive growth in research and development efforts devoted to MEMS devices and packaging. The successfully developed MEMS devices are, for example inkjet, pressure sensors, silicon microphones, accelerometers, gyroscopes, MOEMS, micro fuel cells and emerging MEMS. For the next decade, MEMS/MOEMS and nanodevice based products will penetrate into IT, telecommunications, automotive, defense, life sciences, medical and implantable applications. Forecasts say the MEMS market to be $14 billion by 2012. The packaging cost of MEMS/MOEMS products in general is about 70 percent. Unlike today's electronics IC packaging, their packaging are custom-built and difficult due to the moving structural elements. In order for the moving elements of a MEMS device to move effectively in a well-controlled atmosphere, hermetic sealing of the MEMS device in a cap is necessary. For some MEMS devices, such as resonators and gyroscopes, vacuum packaging is required. Usually, the cap is processed at the wafer level, and thus MEMS packaging is truly a wafer level packaging. In terms of MEMS/MOEMS and nanodevice packaging, there are still many critical issues need to be addressed due to the increasing integration density supported by 3D heterogeneous integration of multi-physic components/layers consisting of photonics, electronics, rf, plasmonics, and wireless. The infrastructure of MEMS/MOEMS and nanodevices and their packaging is not well established yet. Generic packaging platform technologies are not available. Some of critical issues have been studied intensively in the last years. In this paper we will discuss about processes, reliability, testing and characterization of MEMS/MOEMS and nanodevice packaging.

  10. Stability analysis of explicit entropy viscosity methods for non-linear scalar conservation equations

    KAUST Repository

    Bonito, Andrea

    2013-10-03

    We establish the L2-stability of an entropy viscosity technique applied to nonlinear scalar conservation equations. First-and second-order explicit time-stepping techniques using continuous finite elements in space are considered. The method is shown to be stable independently of the polynomial degree of the space approximation under the standard CFL condition. © 2013 American Mathematical Society.

  11. Entropy Coding in HEVC

    OpenAIRE

    Sze, Vivienne; Marpe, Detlev

    2014-01-01

    Context-Based Adaptive Binary Arithmetic Coding (CABAC) is a method of entropy coding first introduced in H.264/AVC and now used in the latest High Efficiency Video Coding (HEVC) standard. While it provides high coding efficiency, the data dependencies in H.264/AVC CABAC make it challenging to parallelize and thus limit its throughput. Accordingly, during the standardization of entropy coding for HEVC, both aspects of coding efficiency and throughput were considered. This chapter describes th...

  12. MEMS-Based Waste Vibrational Energy Harvesters

    Science.gov (United States)

    2013-06-01

    MEMS energy- harvesting device. Although PZT is used more prevalently due to its higher piezoelectric coefficient and dielectric constant, AlN has...7 1. Lead Zirconium Titanate ( PZT ) .........................................................7 2. Aluminum...Laboratory PiezoMUMPS Piezoelectric Multi-User MEMS Processes PZT Lead Zirconate Titanate SEM Scanning Electron Microscopy SiO2 Silicon

  13. Inferring Weighted Directed Association Networks from Multivariate Time Series with the Small-Shuffle Symbolic Transfer Entropy Spectrum Method

    Directory of Open Access Journals (Sweden)

    Yanzhu Hu

    2016-09-01

    Full Text Available Complex network methodology is very useful for complex system exploration. However, the relationships among variables in complex systems are usually not clear. Therefore, inferring association networks among variables from their observed data has been a popular research topic. We propose a method, named small-shuffle symbolic transfer entropy spectrum (SSSTES, for inferring association networks from multivariate time series. The method can solve four problems for inferring association networks, i.e., strong correlation identification, correlation quantification, direction identification and temporal relation identification. The method can be divided into four layers. The first layer is the so-called data layer. Data input and processing are the things to do in this layer. In the second layer, we symbolize the model data, original data and shuffled data, from the previous layer and calculate circularly transfer entropy with different time lags for each pair of time series variables. Thirdly, we compose transfer entropy spectrums for pairwise time series with the previous layer’s output, a list of transfer entropy matrix. We also identify the correlation level between variables in this layer. In the last layer, we build a weighted adjacency matrix, the value of each entry representing the correlation level between pairwise variables, and then get the weighted directed association network. Three sets of numerical simulated data from a linear system, a nonlinear system and a coupled Rossler system are used to show how the proposed approach works. Finally, we apply SSSTES to a real industrial system and get a better result than with two other methods.

  14. Sandia Agile MEMS Prototyping, Layout Tools, Education and Services Program

    Energy Technology Data Exchange (ETDEWEB)

    Schriner, H.; Davies, B.; Sniegowski, J.; Rodgers, M.S.; Allen, J.; Shepard, C.

    1998-05-01

    Research and development in the design and manufacture of Microelectromechanical Systems (MEMS) is growing at an enormous rate. Advances in MEMS design tools and fabrication processes at Sandia National Laboratories` Microelectronics Development Laboratory (MDL) have broadened the scope of MEMS applications that can be designed and manufactured for both military and commercial use. As improvements in micromachining fabrication technologies continue to be made, MEMS designs can become more complex, thus opening the door to an even broader set of MEMS applications. In an effort to further research and development in MEMS design, fabrication, and application, Sandia National Laboratories has launched the Sandia Agile MEMS Prototyping, Layout Tools, Education and Services Program or SAMPLES program. The SAMPLES program offers potential partners interested in MEMS the opportunity to prototype an idea and produce hardware that can be used to sell a concept. The SAMPLES program provides education and training on Sandia`s design tools, analysis tools and fabrication process. New designers can participate in the SAMPLES program and design MEMS devices using Sandia`s design and analysis tools. As part of the SAMPLES program, participants` designs are fabricated using Sandia`s 4 level polycrystalline silicon surface micromachine technology fabrication process known as SUMMiT (Sandia Ultra-planar, Multi-level MEMS Technology). Furthermore, SAMPLES participants can also opt to obtain state of the art, post-fabrication services provided at Sandia such as release, packaging, reliability characterization, and failure analysis. This paper discusses the components of the SAMPLES program.

  15. Entropy of Vaidya-deSitter Spacetime

    Institute of Scientific and Technical Information of China (English)

    LI Xiang; ZHAO Zheng

    2001-01-01

    As a statistical model of black hole entropy, the brick-wall method based on the thermal equilibrium in a large scale cannot be applied to the cases out of equilibrium, such as the non-static hole or the case with two horizons.However, the leading term of hole entropy called the Bekenstein-Hawking entropy comes from the contribution of the field near the horizon. According to this idea, the entropy of Vaidya-deSitter spacetime is calculated. A difference from the static case is that the result proportional to the area of horizon relies on a time-dependent cut-off. The condition of local equilibrium near the horizon is used as a working postulate.

  16. Features of atomic images reconstructed from photoelectron, Auger electron, and internal detector electron holography using SPEA-MEM

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Tomohiro, E-mail: matusita@spring8.or.jp [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan); Matsui, Fumihiko [Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192 (Japan)

    2014-08-15

    Highlights: • We develop a 3D atomic image reconstruction algorithm for photoelectron, Auger electron, and internal detector holography. • We examine the shapes of the atomic images reconstructed by using a developed kernel function. • We examine refraction effect at surface, limitation effect of the hologram data, energy resolution effect, and angular resolution effect. • These discussions indicate the experimental requirements to obtain the clear 3D atomic image. - Abstract: Three-dimensional atomic images can be reconstructed from photoelectron, Auger electron, and internal detector electron holograms using a scattering pattern extraction algorithm using the maximum entropy method (SPEA-MEM) that utilizes an integral transform. An integral kernel function for the integral transform is the key to clear atomic image reconstruction. We composed the kernel function using a scattering pattern function and estimated its ability. Image distortion caused by multiple scattering was also evaluated. Four types of Auger electron wave functions were investigated, and the effect of these wave function types was estimated. In addition, we addressed refraction at the surface, the effects of data limitation, and energy and angular resolutions.

  17. Advantages of PZT thick film for MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lou-Moller, R.; Hansen, K.

    2010-01-01

    For all MEMS devices a high coupling between the mechanical and electrical domain is desired. Figures of merit describing the coupling are important for comparing different piezoelectric materials. The existing figures of merit are discussed and a new figure of merit is introduced for a fair comp....... Improved figure of merit is reached in the piezoelectric PZT thick film, TF2100CIP, by using cold isostatic pressure in the PZT preparation process. The porosity of TF2100 is decreased 38%, hence, allowing an increase of charge sensitivity for MEMS sensors of 59%....... thin film and PZT thick film. It is shown that MEMS sensors with the PZT thick film TF2100 from InSensor A/S have potential for significant higher voltage sensitivities compared to PZT thin film base MEMS sensors when the total thickness of the MEMS cantilever, beam, bridge or membrane is high...

  18. Standard semiconductor packaging for high-reliability low-cost MEMS applications

    Science.gov (United States)

    Harney, Kieran P.

    2005-01-01

    Microelectronic packaging technology has evolved over the years in response to the needs of IC technology. The fundamental purpose of the package is to provide protection for the silicon chip and to provide electrical connection to the circuit board. Major change has been witnessed in packaging and today wafer level packaging technology has further revolutionized the industry. MEMS (Micro Electro Mechanical Systems) technology has created new challenges for packaging that do not exist in standard ICs. However, the fundamental objective of MEMS packaging is the same as traditional ICs, the low cost and reliable presentation of the MEMS chip to the next level interconnect. Inertial MEMS is one of the best examples of the successful commercialization of MEMS technology. The adoption of MEMS accelerometers for automotive airbag applications has created a high volume market that demands the highest reliability at low cost. The suppliers to these markets have responded by exploiting standard semiconductor packaging infrastructures. However, there are special packaging needs for MEMS that cannot be ignored. New applications for inertial MEMS devices are emerging in the consumer space that adds the imperative of small size to the need for reliability and low cost. These trends are not unique to MEMS accelerometers. For any MEMS technology to be successful the packaging must provide the basic reliability and interconnection functions, adding the least possible cost to the product. This paper will discuss the evolution of MEMS packaging in the accelerometer industry and identify the main issues that needed to be addressed to enable the successful commercialization of the technology in the automotive and consumer markets.

  19. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  20. Digital reflection holography based systems development for MEMS testing

    Science.gov (United States)

    Singh, Vijay Raj; Liansheng, Sui; Asundi, Anand

    2010-05-01

    MEMS are tiny mechanical devices that are built onto semiconductor chips and are measured in micrometers and nanometers. Testing of MEMS device is an important part in carrying out their functional assessment and reliability analysis. Development of systems based on digital holography (DH) for MEMS inspection and characterization is presented in this paper. Two DH reflection systems, table-top and handheld types, are developed depending on the MEMS measurement requirements and their capabilities are presented. The methodologies for the systems are developed for 3D profile inspection and static & dynamic measurements, which is further integrated with in-house developed software that provides the measurement results in near real time. The applications of the developed systems are demonstrated for different MEMS devices for 3D profile inspection, static deformation/deflection measurements and vibration analysis. The developed systems are well suitable for the testing of MEMS and Microsystems samples, with full-field, static & dynamic inspection as well as to monitor micro-fabrication process.

  1. MEMS Reliability: Infrastructure, Test Structures, Experiments, and Failure Modes

    Energy Technology Data Exchange (ETDEWEB)

    TANNER,DANELLE M.; SMITH,NORMAN F.; IRWIN,LLOYD W.; EATON,WILLIAM P.; HELGESEN,KAREN SUE; CLEMENT,J. JOSEPH; MILLER,WILLIAM M.; MILLER,SAMUEL L.; DUGGER,MICHAEL T.; WALRAVEN,JEREMY A.; PETERSON,KENNETH A.

    2000-01-01

    The burgeoning new technology of Micro-Electro-Mechanical Systems (MEMS) shows great promise in the weapons arena. We can now conceive of micro-gyros, micro-surety systems, and micro-navigators that are extremely small and inexpensive. Do we want to use this new technology in critical applications such as nuclear weapons? This question drove us to understand the reliability and failure mechanisms of silicon surface-micromachined MEMS. Development of a testing infrastructure was a crucial step to perform reliability experiments on MEMS devices and will be reported here. In addition, reliability test structures have been designed and characterized. Many experiments were performed to investigate failure modes and specifically those in different environments (humidity, temperature, shock, vibration, and storage). A predictive reliability model for wear of rubbing surfaces in microengines was developed. The root causes of failure for operating and non-operating MEMS are discussed. The major failure mechanism for operating MEMS was wear of the polysilicon rubbing surfaces. Reliability design rules for future MEMS devices are established.

  2. Entropy and information

    CERN Document Server

    Volkenstein, Mikhail V

    2009-01-01

    The book "Entropy and Information" deals with the thermodynamical concept of entropy and its relationship to information theory. It is successful in explaining the universality of the term "Entropy" not only as a physical phenomenon, but reveals its existence also in other domains. E.g., Volkenstein discusses the "meaning" of entropy in a biological context and shows how entropy is related to artistic activities. Written by the renowned Russian bio-physicist Mikhail V. Volkenstein, this book on "Entropy and Information" surely serves as a timely introduction to understand entropy from a thermodynamic perspective and is definitely an inspiring and thought-provoking book that should be read by every physicist, information-theorist, biologist, and even artist.

  3. A novel fabrication method of silicon nano-needles using MEMS TMAH etching techniques

    International Nuclear Information System (INIS)

    Yan Sheping; Xu Yang; Yang Junyi; Wang Huiquan; Jin Zhonghe; Wang Yuelin

    2011-01-01

    Nano-needles play important roles in nanoscale operations. However, current nano-needle fabrication is usually expensive and controling the sizes and angles is complicated. We have developed a simple and low cost silicon nano-needle fabrication method using traditional microelectromechanical system (MEMS) tetramethyl ammonium hydroxide (TMAH) etching techniques. We take advantage of the fact that the decrease of the silicon etch rate in TMAH solutions exhibits an inverse fourth power dependence on the boron doping concentration in our nano-needle fabrication. Silicon nano-needles, with high aspect ratio and sharp angles θ as small as 2.9 deg., are obtained, which could be used for bio-sensors and nano-handling procedures, such as penetrating living cells. An analytic model is proposed to explain the etching evolution of the experimental results, which is used to predict the needle angle, length, and etching time. Based on our method, nano-needles with small acute angle θ can be obtained.

  4. Parametric Bayesian Estimation of Differential Entropy and Relative Entropy

    OpenAIRE

    Gupta; Srivastava

    2010-01-01

    Given iid samples drawn from a distribution with known parametric form, we propose the minimization of expected Bregman divergence to form Bayesian estimates of differential entropy and relative entropy, and derive such estimators for the uniform, Gaussian, Wishart, and inverse Wishart distributions. Additionally, formulas are given for a log gamma Bregman divergence and the differential entropy and relative entropy for the Wishart and inverse Wishart. The results, as always with Bayesian est...

  5. Entanglement entropy evolution under double-trace deformation

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yushu [College of Physical Science and Technology, Hebei University, Baoding (China)

    2017-12-15

    In this paper, we study the bulk entanglement entropy evolution in conical BTZ black bole background using the heat kernel method. This is motivated by exploring the new examples where the quantum correction of the entanglement entropy gives the leading contribution. We find that in the large black hole limit the bulk entanglement entropy decreases under the double-trace deformation which is consistent with the holographic c theorem and in the small black hole limit the bulk entanglement entropy increases under the deformation. We also discuss the minimal area correction. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. A novel piezoresistive polymer nanocomposite MEMS accelerometer

    International Nuclear Information System (INIS)

    Seena, V; Hari, K; Prajakta, S; Ramgopal Rao, V; Pratap, Rudra

    2017-01-01

    A novel polymer MEMS (micro electro mechanical systems) accelerometer with photo-patternable polymer nanocomposite as a piezoresistor is presented in this work. Polymer MEMS Accelerometer with beam thicknesses of 3.3 µ m and embedded nanocomposite piezoresistive layer having a gauge factor of 90 were fabricated. The photosensitive nanocomposite samples were prepared and characterized for analyzing the mechanical and electrical properties and thereby ensuring proper process parameters for incorporating the piezoresistive layer into the polymer MEMS accelerometer. The microfabrication process flow and unit processes followed are extremely low cost with process temperatures below 100 °C. This also opens up a new possibility for easy integration of such polymer MEMS with CMOS (complementary metal oxide semiconductor) devices and circuits. The fabricated devices were characterized using laser Doppler vibrometer (LDV) and the devices exhibited a resonant frequency of 10.8 kHz and a response sensitivity of 280 nm g −1 at resonance. The main focus of this paper is on the SU-8/CB nanocomposite piezoresistive MEMS accelerometer technology development which covers the material and the fabrication aspects of these devices. CoventorWare FEA analysis performed using the extracted material properties from the experimental characterization which are in close agreement to performance parameters of the fabricated devices is also discussed. The simulated piezoresistive polymer MEMS devices showed an acceleration sensitivity of 126 nm g −1 and 82 ppm of Δ R / R per 1 g of acceleration. (paper)

  7. Cost-Efficient Wafer-Level Capping for MEMS and Imaging Sensors by Adhesive Wafer Bonding

    Directory of Open Access Journals (Sweden)

    Simon J. Bleiker

    2016-10-01

    Full Text Available Device encapsulation and packaging often constitutes a substantial part of the fabrication cost of micro electro-mechanical systems (MEMS transducers and imaging sensor devices. In this paper, we propose a simple and cost-effective wafer-level capping method that utilizes a limited number of highly standardized process steps as well as low-cost materials. The proposed capping process is based on low-temperature adhesive wafer bonding, which ensures full complementary metal-oxide-semiconductor (CMOS compatibility. All necessary fabrication steps for the wafer bonding, such as cavity formation and deposition of the adhesive, are performed on the capping substrate. The polymer adhesive is deposited by spray-coating on the capping wafer containing the cavities. Thus, no lithographic patterning of the polymer adhesive is needed, and material waste is minimized. Furthermore, this process does not require any additional fabrication steps on the device wafer, which lowers the process complexity and fabrication costs. We demonstrate the proposed capping method by packaging two different MEMS devices. The two MEMS devices include a vibration sensor and an acceleration switch, which employ two different electrical interconnection schemes. The experimental results show wafer-level capping with excellent bond quality due to the re-flow behavior of the polymer adhesive. No impediment to the functionality of the MEMS devices was observed, which indicates that the encapsulation does not introduce significant tensile nor compressive stresses. Thus, we present a highly versatile, robust, and cost-efficient capping method for components such as MEMS and imaging sensors.

  8. Configurational entropy of hydrogen-disordered ice polymorphs

    International Nuclear Information System (INIS)

    Herrero, Carlos P.; Ramírez, Rafael

    2014-01-01

    The configurational entropy of several H-disordered ice polymorphs is calculated by means of a thermodynamic integration along a path between a totally H-disordered state and one fulfilling the Bernal-Fowler ice rules. A Monte Carlo procedure based on a simple energy model is used, so that the employed thermodynamic path drives the system from high temperatures to the low-temperature limit. This method turns out to be precise enough to give reliable values for the configurational entropy s th of different ice phases in the thermodynamic limit (number of molecules N → ∞). The precision of the method is checked for the ice model on a two-dimensional square lattice. Results for the configurational entropy are given for H-disordered arrangements on several polymorphs, including ices Ih, Ic, II, III, IV, V, VI, and XII. The highest and lowest entropy values correspond to ices VI and XII, respectively, with a difference of 3.3% between them. The dependence of the entropy on the ice structures has been rationalized by comparing it with structural parameters of the various polymorphs, such as the mean ring size. A particularly good correlation has been found between the configurational entropy and the connective constant derived from self-avoiding walks on the ice networks

  9. Nonadditive entropy maximization is inconsistent with Bayesian updating

    Science.gov (United States)

    Pressé, Steve

    2014-11-01

    The maximum entropy method—used to infer probabilistic models from data—is a special case of Bayes's model inference prescription which, in turn, is grounded in basic propositional logic. By contrast to the maximum entropy method, the compatibility of nonadditive entropy maximization with Bayes's model inference prescription has never been established. Here we demonstrate that nonadditive entropy maximization is incompatible with Bayesian updating and discuss the immediate implications of this finding. We focus our attention on special cases as illustrations.

  10. Maximum entropy methods for extracting the learned features of deep neural networks.

    Science.gov (United States)

    Finnegan, Alex; Song, Jun S

    2017-10-01

    New architectures of multilayer artificial neural networks and new methods for training them are rapidly revolutionizing the application of machine learning in diverse fields, including business, social science, physical sciences, and biology. Interpreting deep neural networks, however, currently remains elusive, and a critical challenge lies in understanding which meaningful features a network is actually learning. We present a general method for interpreting deep neural networks and extracting network-learned features from input data. We describe our algorithm in the context of biological sequence analysis. Our approach, based on ideas from statistical physics, samples from the maximum entropy distribution over possible sequences, anchored at an input sequence and subject to constraints implied by the empirical function learned by a network. Using our framework, we demonstrate that local transcription factor binding motifs can be identified from a network trained on ChIP-seq data and that nucleosome positioning signals are indeed learned by a network trained on chemical cleavage nucleosome maps. Imposing a further constraint on the maximum entropy distribution also allows us to probe whether a network is learning global sequence features, such as the high GC content in nucleosome-rich regions. This work thus provides valuable mathematical tools for interpreting and extracting learned features from feed-forward neural networks.

  11. Poly-SiGe for MEMS-above-CMOS sensors

    CERN Document Server

    Gonzalez Ruiz, Pilar; Witvrouw, Ann

    2014-01-01

    Polycrystalline SiGe has emerged as a promising MEMS (Microelectromechanical Systems) structural material since it provides the desired mechanical properties at lower temperatures compared to poly-Si, allowing the direct post-processing on top of CMOS. This CMOS-MEMS monolithic integration can lead to more compact MEMS with improved performance. The potential of poly-SiGe for MEMS above-aluminum-backend CMOS integration has already been demonstrated. However, aggressive interconnect scaling has led to the replacement of the traditional aluminum metallization by copper (Cu) metallization, due to its lower resistivity and improved reliability. Poly-SiGe for MEMS-above-CMOS sensors demonstrates the compatibility of poly-SiGe with post-processing above the advanced CMOS technology nodes through the successful fabrication of an integrated poly-SiGe piezoresistive pressure sensor, directly fabricated above 0.13 m Cu-backend CMOS. Furthermore, this book presents the first detailed investigation on the influence o...

  12. High Volume Manufacturing and Field Stability of MEMS Products

    Science.gov (United States)

    Martin, Jack

    Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are

  13. Quantum dynamical entropy revisited

    International Nuclear Information System (INIS)

    Hudetz, T.

    1996-10-01

    We define a new quantum dynamical entropy, which is a 'hybrid' of the closely related, physically oriented entropy introduced by Alicki and Fannes in 1994, and of the mathematically well-developed, single-argument entropy introduced by Connes, Narnhofer and Thirring in 1987. We show that this new quantum dynamical entropy has many properties similar to the ones of the Alicki-Fannes entropy, and also inherits some additional properties from the CNT entropy. In particular, the 'hybrid' entropy interpolates between the two different ways in which both the AF and the CNT entropy of the shift automorphism on the quantum spin chain agree with the usual quantum entropy density, resulting in even better agreement. Also, the new quantum dynamical entropy generalizes the classical dynamical entropy of Kolmogorov and Sinai in the same way as does the AF entropy. Finally, we estimate the 'hybrid' entropy both for the Powers-Price shift systems and for the noncommutative Arnold map on the irrational rotation C * -algebra, leaving some interesting open problems. (author)

  14. Spatial-dependence recurrence sample entropy

    Science.gov (United States)

    Pham, Tuan D.; Yan, Hong

    2018-03-01

    Measuring complexity in terms of the predictability of time series is a major area of research in science and engineering, and its applications are spreading throughout many scientific disciplines, where the analysis of physiological signals is perhaps the most widely reported in literature. Sample entropy is a popular measure for quantifying signal irregularity. However, the sample entropy does not take sequential information, which is inherently useful, into its calculation of sample similarity. Here, we develop a method that is based on the mathematical principle of the sample entropy and enables the capture of sequential information of a time series in the context of spatial dependence provided by the binary-level co-occurrence matrix of a recurrence plot. Experimental results on time-series data of the Lorenz system, physiological signals of gait maturation in healthy children, and gait dynamics in Huntington's disease show the potential of the proposed method.

  15. Multi-Scale Entropy Analysis as a Method for Time-Series Analysis of Climate Data

    Directory of Open Access Journals (Sweden)

    Heiko Balzter

    2015-03-01

    Full Text Available Evidence is mounting that the temporal dynamics of the climate system are changing at the same time as the average global temperature is increasing due to multiple climate forcings. A large number of extreme weather events such as prolonged cold spells, heatwaves, droughts and floods have been recorded around the world in the past 10 years. Such changes in the temporal scaling behaviour of climate time-series data can be difficult to detect. While there are easy and direct ways of analysing climate data by calculating the means and variances for different levels of temporal aggregation, these methods can miss more subtle changes in their dynamics. This paper describes multi-scale entropy (MSE analysis as a tool to study climate time-series data and to identify temporal scales of variability and their change over time in climate time-series. MSE estimates the sample entropy of the time-series after coarse-graining at different temporal scales. An application of MSE to Central European, variance-adjusted, mean monthly air temperature anomalies (CRUTEM4v is provided. The results show that the temporal scales of the current climate (1960–2014 are different from the long-term average (1850–1960. For temporal scale factors longer than 12 months, the sample entropy increased markedly compared to the long-term record. Such an increase can be explained by systems theory with greater complexity in the regional temperature data. From 1961 the patterns of monthly air temperatures are less regular at time-scales greater than 12 months than in the earlier time period. This finding suggests that, at these inter-annual time scales, the temperature variability has become less predictable than in the past. It is possible that climate system feedbacks are expressed in altered temporal scales of the European temperature time-series data. A comparison with the variance and Shannon entropy shows that MSE analysis can provide additional information on the

  16. Entropy stable high order discontinuous Galerkin methods for ideal compressible MHD on structured meshes

    Science.gov (United States)

    Liu, Yong; Shu, Chi-Wang; Zhang, Mengping

    2018-02-01

    We present a discontinuous Galerkin (DG) scheme with suitable quadrature rules [15] for ideal compressible magnetohydrodynamic (MHD) equations on structural meshes. The semi-discrete scheme is analyzed to be entropy stable by using the symmetrizable version of the equations as introduced by Godunov [32], the entropy stable DG framework with suitable quadrature rules [15], the entropy conservative flux in [14] inside each cell and the entropy dissipative approximate Godunov type numerical flux at cell interfaces to make the scheme entropy stable. The main difficulty in the generalization of the results in [15] is the appearance of the non-conservative "source terms" added in the modified MHD model introduced by Godunov [32], which do not exist in the general hyperbolic system studied in [15]. Special care must be taken to discretize these "source terms" adequately so that the resulting DG scheme satisfies entropy stability. Total variation diminishing / bounded (TVD/TVB) limiters and bound-preserving limiters are applied to control spurious oscillations. We demonstrate the accuracy and robustness of this new scheme on standard MHD examples.

  17. Amorphous Diamond MEMS and Sensors

    Energy Technology Data Exchange (ETDEWEB)

    SULLIVAN, JOHN P.; FRIEDMANN, THOMAS A.; ASHBY, CAROL I.; DE BOER, MAARTEN P.; SCHUBERT, W. KENT; SHUL, RANDY J.; HOHLFELDER, ROBERT J.; LAVAN, D.A.

    2002-06-01

    This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater

  18. Angular momentum independence of the entropy sum and entropy product for AdS rotating black holes in all dimensions

    Directory of Open Access Journals (Sweden)

    Hang Liu

    2016-08-01

    Full Text Available In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions d>4 with at least one rotation parameter ai=0, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions (d>4 and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affect the angular momentum-free of entropy sum and product but the criterion for angular momentum-independence of entropy product will be affected.

  19. Nernst Theorem and Statistical Entropy of 5-Dimensional Rotating Black Hole

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ren; WU Yue-Qin; ZHANG Li-Chun

    2003-01-01

    In this paper, by using quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of the 5-dimensional rotating black hole. Then via the improved brick-wall method and membrane model, we calculate the entropy of Bose field and Fermi field of the black hole. And it is obtained that the entropy of the black hole is not only related to the area of the outer horizon but also is the function of inner horizon's area. In our results, there are not the left out term and the divergent logarithmic term in the original brick-wall method.The doubt that why the entropy of the scalar or Dirac field outside the event horizon is the entropy of the black hole in the original brick-wall method does not exist. The influence of spinning degeneracy of particles on entropy of the black hole is also given. It is shown that the entropy determined by the areas of the inner and outer horizons will approach zero,when the radiation temperature of the black hole approaches absolute zero. It satisfies Nernst theorem. The entropy can be taken as the Planck absolute entropy. We provide a way to study higher dimensional black hole.

  20. On Using Entropy for Enhancing Handwriting Preprocessing

    Directory of Open Access Journals (Sweden)

    Bernhard Peischl

    2012-11-01

    Full Text Available Handwriting is an important modality for Human-Computer Interaction. For medical professionals, handwriting is (still the preferred natural method of documentation. Handwriting recognition has long been a primary research area in Computer Science. With the tremendous ubiquity of smartphones, along with the renaissance of the stylus, handwriting recognition has become a new impetus. However, recognition rates are still not 100% perfect, and researchers still are constantly improving handwriting algorithms. In this paper we evaluate the performance of entropy based slant- and skew-correction, and compare the results to other methods. We selected 3700 words of 23 writers out of the Unipen-ICROW-03 benchmark set, which we annotated with their associated error angles by hand. Our results show that the entropy-based slant correction method outperforms a window based approach with an average precision of 6:02 for the entropy-based method, compared with the 7:85 for the alternative. On the other hand, the entropy-based skew correction yields a lower average precision of 2:86, compared with the average precision of 2:13 for the alternative LSM based approach.

  1. MEMS tunable grating micro-spectrometer

    Science.gov (United States)

    Tormen, Maurizio; Lockhart, R.; Niedermann, P.; Overstolz, T.; Hoogerwerf, A.; Mayor, J.-M.; Pierer, J.; Bosshard, C.; Ischer, R.; Voirin, G.; Stanley, R. P.

    2017-11-01

    The interest in MEMS based Micro-Spectrometers is increasing due to their potential in terms of flexibility as well as cost, low mass, small volume and power savings. This interest, especially in the Near-Infrared and Mid- Infrared, ranges from planetary exploration missions to astronomy, e.g. the search for extra solar planets, as well as to many other terrestrial fields of application such as, industrial quality and surface control, chemical analysis of soil and water, detection of chemical pollutants, exhausted gas analysis, food quality control, process control in pharmaceuticals, to name a few. A compact MEMS-based Spectrometer for Near- Infrared and Mid-InfraRed operation have been conceived, designed and demonstrated. The design based on tunable MEMS blazed grating, developed in the past at CSEM [1], achieves state of the art results in terms of spectral resolution, operational wavelength range, light throughput, overall dimensions, and power consumption.

  2. Micro-Electromechanical-Systems (MEMS) technologies for aerospace applications in Canada

    International Nuclear Information System (INIS)

    Pimprikar, M.

    2001-01-01

    During the last decade, research and development of Micro-Electro-Mechanical Systems (MEMS) have shown significant promise for a variety of aerospace applications. The advantages of drastic size and weight reduction of MEMS enables consideration of developing low-cost, high-performance, ultra-portable, MEMS-based devices and systems for aircraft, space and defense requirements. 'Microelectromechanical Systems, or MEMS', are integrated microdevices or systems combining electrical and mechanical components, fabricated using integrated circuit compatible batch-processing techniques, and varying in size from micrometers to millimeters. In the 1990's, MEMS were used as laboratory curiosities with very low power, short lifetimes and few concrete applications. One decade later, MEMS have taken major roles in several industries, the total world market is expected to grow from $14 billion to over $40 billion by the year 2002. A typical device contains micromechanical structures that move by flexing (membranes, cantilevers, springs) and MEMS/MOEMS level where the integration of microelectronics, micromechanics and optics form a complete system (sensor, actuator, photonic device). (author)

  3. Quantum chaos: entropy signatures

    International Nuclear Information System (INIS)

    Miller, P.A.; Sarkar, S.; Zarum, R.

    1998-01-01

    A definition of quantum chaos is given in terms of entropy production rates for a quantum system coupled weakly to a reservoir. This allows the treatment of classical and quantum chaos on the same footing. In the quantum theory the entropy considered is the von Neumann entropy and in classical systems it is the Gibbs entropy. The rate of change of the coarse-grained Gibbs entropy of the classical system with time is given by the Kolmogorov-Sinai (KS) entropy. The relation between KS entropy and the rate of change of von Neumann entropy is investigated for the kicked rotator. For a system which is classically chaotic there is a linear relationship between these two entropies. Moreover it is possible to construct contour plots for the local KS entropy and compare it with the corresponding plots for the rate of change of von Neumann entropy. The quantitative and qualitative similarities of these plots are discussed for the standard map (kicked rotor) and the generalised cat maps. (author)

  4. Nano-scale measurement of sub-micrometer MEMS in-plane dynamics using synchronized illumination

    International Nuclear Information System (INIS)

    Warnat, S; Forbrigger, C; Kujath, M; Hubbard, T

    2015-01-01

    A method for measuring the sub-micrometer in-plane dynamics of MEMS devices with nano-scale precision using a CCD camera and synchronized pulsating illumination is presented. Typical MEMS actuators have fast responses (generally in the 1–200 kHz range), much faster than typical cameras which record a time averaged motion. Under constant illumination the average displacement is steady state and independent of dynamic amplitude or phase. Methods such as strobe illumination use short light pulses to freeze the motion. This paper develops the use of longer pulses of illumination that do not freeze the image, but make the average displacement depend on dynamic amplitude and phase; thus allowing both properties to be extracted. The expected signal is derived as a function of light pulse width and delay, and short versus longer pulses are compared. Measurements using a conventional microscope with replacement of the lamp with LEDs confirmed the derived equations. The system was used to measure sub-micrometer motion of MEMS actuators with ∼5 nm precision. The time constant of a thermal actuator was measured and found to be 48 µs. A resonant peak of a MEMS device was measured at 123.30 kHz with an amplitude of 238 nm. (paper)

  5. Modeling and Compensation of Random Drift of MEMS Gyroscopes Based on Least Squares Support Vector Machine Optimized by Chaotic Particle Swarm Optimization.

    Science.gov (United States)

    Xing, Haifeng; Hou, Bo; Lin, Zhihui; Guo, Meifeng

    2017-10-13

    MEMS (Micro Electro Mechanical System) gyroscopes have been widely applied to various fields, but MEMS gyroscope random drift has nonlinear and non-stationary characteristics. It has attracted much attention to model and compensate the random drift because it can improve the precision of inertial devices. This paper has proposed to use wavelet filtering to reduce noise in the original data of MEMS gyroscopes, then reconstruct the random drift data with PSR (phase space reconstruction), and establish the model for the reconstructed data by LSSVM (least squares support vector machine), of which the parameters were optimized using CPSO (chaotic particle swarm optimization). Comparing the effect of modeling the MEMS gyroscope random drift with BP-ANN (back propagation artificial neural network) and the proposed method, the results showed that the latter had a better prediction accuracy. Using the compensation of three groups of MEMS gyroscope random drift data, the standard deviation of three groups of experimental data dropped from 0.00354°/s, 0.00412°/s, and 0.00328°/s to 0.00065°/s, 0.00072°/s and 0.00061°/s, respectively, which demonstrated that the proposed method can reduce the influence of MEMS gyroscope random drift and verified the effectiveness of this method for modeling MEMS gyroscope random drift.

  6. Deep coupling of star tracker and MEMS-gyro data under highly dynamic and long exposure conditions

    Science.gov (United States)

    Sun, Ting; Xing, Fei; You, Zheng; Wang, Xiaochu; Li, Bin

    2014-08-01

    Star trackers and gyroscopes are the two most widely used attitude measurement devices in spacecrafts. The star tracker is supposed to have the highest accuracy in stable conditions among different types of attitude measurement devices. In general, to detect faint stars and reduce the size of the star tracker, a method with long exposure time method is usually used. Thus, under dynamic conditions, smearing of the star image may appear and result in decreased accuracy or even failed extraction of the star spot. This may cause inaccuracies in attitude measurement. Gyros have relatively good dynamic performance and are usually used in combination with star trackers. However, current combination methods focus mainly on the data fusion of the output attitude data levels, which are inadequate for utilizing and processing internal blurred star image information. A method for tracking deep coupling stars and MEMS-gyro data is proposed in this work. The method achieves deep fusion at the star image level. First, dynamic star image processing is performed based on the angular velocity information of the MEMS-gyro. Signal-to-noise ratio (SNR) of the star spot could be improved, and extraction is achieved more effectively. Then, a prediction model for optimal estimation of the star spot position is obtained through the MEMS-gyro, and an extended Kalman filter is introduced. Meanwhile, the MEMS-gyro drift can be estimated and compensated though the proposed method. These enable the star tracker to achieve high star centroid determination accuracy under dynamic conditions. The MEMS-gyro drift can be corrected even when attitude data of the star tracker are unable to be solved and only one navigation star is captured in the field of view. Laboratory experiments were performed to verify the effectiveness of the proposed method and the whole system.

  7. The information entropy of a static dilaton black hole

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In accordance with holographic principle, by calculating the statistical entropy of the quantum field just at the event horizon of the Garfinkle-Horowitz-Strominger dilaton black hole, the information entropy of the black hole was investigated and the Bekenstein-Hawking formula was obtained. The results show that black hole entropy is identical with the statistical entropy of the quantum field at the horizon. Using the generalized uncertainty relation, the divergence of the state density near the event horizon in usual quantum field theory was removed, and the cutoffs and the little mass approximation in the heat gas method of black hole entropy were avoided. Thus, the microstates of the massive scalar field just at the event horizon of the static dilaton black hole were studied directly and a description on holograph principle was presented. By using residue theorem, the integral difficulty in the calculation was overcome, and the information entropy and the Bekenstein-Hawking formula were obtained quantitatively. Compared with the black hole entropy from the loop quantum gravity, the consistency of methods and results of calculating black hole entropy in non-commutative quantum field theory and loop quantum gravity was investigated. By this, the gravity correction constant in the generalized uncertainty relation was suggested and the sense of holographic principle was discussed.

  8. Evolution of a MEMS Photoacoustic Chemical Sensor

    National Research Council Canada - National Science Library

    Pellegrino, Paul M; Polcawich, Ronald G

    2003-01-01

    .... Initial MEMS work is centered on fabrication of a lead zirconate titanate (PZT) microphone subsystem to be incorporated in the full photoacoustic device. Preliminary results were very positive for the macro-photoacoustic cell, PZT membrane microphones design / fabrication and elementary monolithic MEMS photoacoustic cavity.

  9. Comparing Postural Stability Entropy Analyses to Differentiate Fallers and Non-fallers.

    Science.gov (United States)

    Fino, Peter C; Mojdehi, Ahmad R; Adjerid, Khaled; Habibi, Mohammad; Lockhart, Thurmon E; Ross, Shane D

    2016-05-01

    The health and financial cost of falls has spurred research to differentiate the characteristics of fallers and non-fallers. Postural stability has received much of the attention with recent studies exploring various measures of entropy. This study compared the discriminatory ability of several entropy methods at differentiating two paradigms in the center-of-pressure of elderly individuals: (1) eyes open (EO) vs. eyes closed (EC) and (2) fallers (F) vs. non-fallers (NF). Methods were compared using the area under the curve (AUC) of the receiver-operating characteristic curves developed from logistic regression models. Overall, multiscale entropy (MSE) and composite multiscale entropy (CompMSE) performed the best with AUCs of 0.71 for EO/EC and 0.77 for F/NF. When methods were combined together to maximize the AUC, the entropy classifier had an AUC of for 0.91 the F/NF comparison. These results suggest researchers and clinicians attempting to create clinical tests to identify fallers should consider a combination of every entropy method when creating a classifying test. Additionally, MSE and CompMSE classifiers using polar coordinate data outperformed rectangular coordinate data, encouraging more research into the most appropriate time series for postural stability entropy analysis.

  10. An Entropy Stable h/p Non-Conforming Discontinuous Galerkin Method with the Summation-by-Parts Property

    KAUST Repository

    Friedrich, Lucas; Winters, Andrew R.; Ferná ndez, David C. Del Rey; Gassner, Gregor J.; Parsani, Matteo; Carpenter, Mark H.

    2017-01-01

    analysis are discretely mimicked. Special attention is given to the coupling between nonconforming elements as we demonstrate that the standard mortar approach for DG methods does not guarantee entropy stability for non-linear problems, which can lead

  11. Cost-effective method of manufacturing a 3D MEMS optical switch

    Science.gov (United States)

    Carr, Emily; Zhang, Ping; Keebaugh, Doug; Chau, Kelvin

    2009-02-01

    growth of data and video transport networks. All-optical switching eliminates the need for optical-electrical conversion offering the ability to switch optical signals transparently: independent of data rates, formats and wavelength. It also provides network operators much needed automation capabilities to create, monitor and protect optical light paths. To further accelerate the market penetration, it is necessary to identify a path to reduce the manufacturing cost significantly as well as enhance the overall system performance, uniformity and reliability. Currently, most MEMS optical switches are assembled through die level flip-chip bonding with either epoxies or solder bumps. This is due to the alignment accuracy requirements of the switch assembly, defect matching of individual die, and cost of the individual components. In this paper, a wafer level assembly approach is reported based on silicon fusion bonding which aims to reduce the packaging time, defect count and cost through volume production. This approach is successfully demonstrated by the integration of two 6-inch wafers: a mirror array wafer and a "snap-guard" wafer, which provides a mechanical structure on top of the micromirror to prevent electrostatic snap-down. The direct silicon-to-silicon bond eliminates the CTEmismatch and stress issues caused by non-silicon bonding agents. Results from a completed integrated switch assembly will be presented, which demonstrates the reliability and uniformity of some key parameters of this MEMS optical switch.

  12. Wavelength tunable MEMS VCSELs for OCT imaging

    DEFF Research Database (Denmark)

    Sahoo, Hitesh Kumar; Ansbæk, Thor; Ottaviano, Luisa

    2018-01-01

    MEMS VCSELs are one of the most promising swept source (SS) lasers for optical coherence tomography (OCT) and one of the best candidates for future integration with endoscopes, surgical probes and achieving an integrated OCT system. However, the current MEMS-based SS are processed on the III...

  13. Construction and Initial Validation of the Multiracial Experiences Measure (MEM)

    Science.gov (United States)

    Yoo, Hyung Chol; Jackson, Kelly; Guevarra, Rudy P.; Miller, Matthew J.; Harrington, Blair

    2015-01-01

    This article describes the development and validation of the Multiracial Experiences Measure (MEM): a new measure that assesses uniquely racialized risks and resiliencies experienced by individuals of mixed racial heritage. Across two studies, there was evidence for the validation of the 25-item MEM with 5 subscales including Shifting Expressions, Perceived Racial Ambiguity, Creating Third Space, Multicultural Engagement, and Multiracial Discrimination. The 5-subscale structure of the MEM was supported by a combination of exploratory and confirmatory factor analyses. Evidence of criterion-related validity was partially supported with MEM subscales correlating with measures of racial diversity in one’s social network, color-blind racial attitude, psychological distress, and identity conflict. Evidence of discriminant validity was supported with MEM subscales not correlating with impression management. Implications for future research and suggestions for utilization of the MEM in clinical practice with multiracial adults are discussed. PMID:26460977

  14. Distinguishing Stationary/Nonstationary Scaling Processes Using Wavelet Tsallis q-Entropies

    Directory of Open Access Journals (Sweden)

    Julio Ramirez Pacheco

    2012-01-01

    Full Text Available Classification of processes as stationary or nonstationary has been recognized as an important and unresolved problem in the analysis of scaling signals. Stationarity or nonstationarity determines not only the form of autocorrelations and moments but also the selection of estimators. In this paper, a methodology for classifying scaling processes as stationary or nonstationary is proposed. The method is based on wavelet Tsallis q-entropies and particularly on the behaviour of these entropies for scaling signals. It is demonstrated that the observed wavelet Tsallis q-entropies of 1/f signals can be modeled by sum-cosh apodizing functions which allocates constant entropies to a set of scaling signals and varying entropies to the rest and that this allocation is controlled by q. The proposed methodology, therefore, differentiates stationary signals from non-stationary ones based on the observed wavelet Tsallis entropies for 1/f signals. Experimental studies using synthesized signals confirm that the proposed method not only achieves satisfactorily classifications but also outperforms current methods proposed in the literature.

  15. SOI silicon on glass for optical MEMS

    DEFF Research Database (Denmark)

    Larsen, Kristian Pontoppidan; Ravnkilde, Jan Tue; Hansen, Ole

    2003-01-01

    and a final sealing at the interconnects can be performed using a suitable polymer. Packaged MEMS on glass are advantageous within Optical MEMS and for sensitive capacitive devices. We report on experiences with bonding SOI to Pyrex. Uniform DRIE shallow and deep etching was achieved by a combination......A newly developed fabrication method for fabrication of single crystalline Si (SCS) components on glass, utilizing Deep Reactive Ion Etching (DRIE) of a Silicon On Insulator (SOI) wafer is presented. The devices are packaged at wafer level in a glass-silicon-glass (GSG) stack by anodic bonding...... of an optimized device layout and an optimized process recipe. The behavior of the buried oxide membrane when used as an etch stop for the through-hole etch is described. No harmful buckling or fracture of the membrane is observed for an oxide thickness below 1 μm, but larger and more fragile released structures...

  16. Entropy of Reissner-Nordstrom-De Sitter Black Hole in Nonthermal Equilibrium

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ren; ZHANG Jun-Fang; ZHANG Li-Chun

    2002-01-01

    By making use of the method of quantum statistics, we directly derive the partition function of bosonic and fermionic fields in Reissner-Nordstrom-De Sitter black hole and obtain the integral expression of black hole's entropy and the entropy to which the cosmic horizon surface corresponds. It avoids the difficulty in solving the wave equation of various particles. Then via the improved brick-wall method, i.e. the membrane model, we calculate black hole's entropy and cosmic entropy and find out that if we let the integral upper limit and lower limit both tend to the horizon, the entropy of black hole is proportional to the area of horizon and the entropy to which cosmic horizon surface corresponds is proportional to the area of cosmic horizon. In our result, the stripped term and the divergent logarithmic term in the original brick-wall method no longer exist. In the whole process, the physical idea is clear and the calculation is simple.We offer a new simple and direct way for calculating the entropy of different complicated black holes.

  17. Advanced MEMS systems for optical communication and imaging

    International Nuclear Information System (INIS)

    Horenstein, M N; Sumner, R; Freedman, D S; Datta, M; Kani, N; Miller, P; Stewart, J B; Cornelissen, S

    2011-01-01

    Optical communication and adaptive optics have emerged as two important uses of micro-electromechanical (MEMS) devices based on electrostatic actuation. Each application uses a mirror whose surface is altered by applying voltages of up to 300 V. Previous generations of adaptive-optic mirrors were large (∼1 m) and required the use of piezoelectric transducers. Beginning in the mid-1990s, a new class of small MEMS mirrors (∼1 cm) were developed. These mirrors are now a commercially available, mature technology. This paper describes three advanced applications of MEMS mirrors. The first is a mirror used for corona-graphic imaging, whereby an interferometric telescope blocks the direct light from a distant star so that nearby objects such as planets can be seen. We have developed a key component of the system: a 144-channel, fully-scalable, high-voltage multiplexer that reduces power consumption to only a few hundred milliwatts. In a second application, a MEMS mirror comprises part of a two-way optical communication system in which only one node emits a laser beam. The other node is passive, incorporating a retro-reflective, electrostatic MEMS mirror that digitally encodes the reflected beam. In a third application, the short (∼100-ns) pulses of a commercially-available laser rangefinder are returned by the MEMS mirror as a digital data stream. Suitable low-power drive systems comprise part of the system design.

  18. In vivo cellular imaging with microscopes enabled by MEMS scanners

    Science.gov (United States)

    Ra, Hyejun

    High-resolution optical imaging plays an important role in medical diagnosis and biomedical research. Confocal microscopy is a widely used imaging method for obtaining cellular and sub-cellular images of biological tissue in reflectance and fluorescence modes. Its characteristic optical sectioning capability also enables three-dimensional (3-D) image reconstruction. However, its use has mostly been limited to excised tissues due to the requirement of high numerical aperture (NA) lenses for cellular resolution. Microscope miniaturization can enable in vivo imaging to make possible early cancer diagnosis and biological studies in the innate environment. In this dissertation, microscope miniaturization for in vivo cellular imaging is presented. The dual-axes confocal (DAC) architecture overcomes limitations of the conventional single-axis confocal (SAC) architecture to allow for miniaturization with high resolution. A microelectromechanical systems (MEMS) scanner is the central imaging component that is key in miniaturization of the DAC architecture. The design, fabrication, and characterization of the two-dimensional (2-D) MEMS scanner are presented. The gimbaled MEMS scanner is fabricated on a double silicon-on-insulator (SOI) wafer and is actuated by self-aligned vertical electrostatic combdrives. The imaging performance of the MEMS scanner in a DAC configuration is shown in a breadboard microscope setup, where reflectance and fluorescence imaging is demonstrated. Then, the MEMS scanner is integrated into a miniature DAC microscope. The whole imaging system is integrated into a portable unit for research in small animal models of human biology and disease. In vivo 3-D imaging is demonstrated on mouse skin models showing gene transfer and siRNA silencing. The siRNA silencing process is sequentially imaged in one mouse over time.

  19. Recent Progress in Silicon Mems Oscillators

    Science.gov (United States)

    2008-12-01

    MEMS oscillator. As shown, a MEMS resonator is connected to an IC. The reference oscillator, which is basically a transimpedance amplifier ...small size), and (3) DC bias voltage required to operate the resonators. As a result, instead of Colpitts or Pierce architecture, a transimpedence ... amplifier is typically used for sustain the oscillation. The frequency of the resonators is determined by both material properties and geometry of

  20. A Generalized Polynomial Chaos-Based Approach to Analyze the Impacts of Process Deviations on MEMS Beams.

    Science.gov (United States)

    Gao, Lili; Zhou, Zai-Fa; Huang, Qing-An

    2017-11-08

    A microstructure beam is one of the fundamental elements in MEMS devices like cantilever sensors, RF/optical switches, varactors, resonators, etc. It is still difficult to precisely predict the performance of MEMS beams with the current available simulators due to the inevitable process deviations. Feasible numerical methods are required and can be used to improve the yield and profits of the MEMS devices. In this work, process deviations are considered to be stochastic variables, and a newly-developed numerical method, i.e., generalized polynomial chaos (GPC), is applied for the simulation of the MEMS beam. The doubly-clamped polybeam has been utilized to verify the accuracy of GPC, compared with our Monte Carlo (MC) approaches. Performance predictions have been made on the residual stress by achieving its distributions in GaAs Monolithic Microwave Integrated Circuit (MMIC)-based MEMS beams. The results show that errors are within 1% for the results of GPC approximations compared with the MC simulations. Appropriate choices of the 4-order GPC expansions with orthogonal terms have also succeeded in reducing the MC simulation labor. The mean value of the residual stress, concluded from experimental tests, shares an error about 1.1% with that of the 4-order GPC method. It takes a probability around 54.3% for the 4-order GPC approximation to attain the mean test value of the residual stress. The corresponding yield occupies over 90 percent around the mean within the twofold standard deviations.

  1. A Generalized Polynomial Chaos-Based Approach to Analyze the Impacts of Process Deviations on MEMS Beams

    Directory of Open Access Journals (Sweden)

    Lili Gao

    2017-11-01

    Full Text Available A microstructure beam is one of the fundamental elements in MEMS devices like cantilever sensors, RF/optical switches, varactors, resonators, etc. It is still difficult to precisely predict the performance of MEMS beams with the current available simulators due to the inevitable process deviations. Feasible numerical methods are required and can be used to improve the yield and profits of the MEMS devices. In this work, process deviations are considered to be stochastic variables, and a newly-developed numerical method, i.e., generalized polynomial chaos (GPC, is applied for the simulation of the MEMS beam. The doubly-clamped polybeam has been utilized to verify the accuracy of GPC, compared with our Monte Carlo (MC approaches. Performance predictions have been made on the residual stress by achieving its distributions in GaAs Monolithic Microwave Integrated Circuit (MMIC-based MEMS beams. The results show that errors are within 1% for the results of GPC approximations compared with the MC simulations. Appropriate choices of the 4-order GPC expansions with orthogonal terms have also succeeded in reducing the MC simulation labor. The mean value of the residual stress, concluded from experimental tests, shares an error about 1.1% with that of the 4-order GPC method. It takes a probability around 54.3% for the 4-order GPC approximation to attain the mean test value of the residual stress. The corresponding yield occupies over 90 percent around the mean within the twofold standard deviations.

  2. Order and correlation contributions to the entropy of hydrophobic solvation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Maoyuan; Besford, Quinn Alexander; Mulvaney, Thomas; Gray-Weale, Angus, E-mail: gusgw@gusgw.net [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia)

    2015-03-21

    The entropy of hydrophobic solvation has been explained as the result of ordered solvation structures, of hydrogen bonds, of the small size of the water molecule, of dispersion forces, and of solvent density fluctuations. We report a new approach to the calculation of the entropy of hydrophobic solvation, along with tests of and comparisons to several other methods. The methods are assessed in the light of the available thermodynamic and spectroscopic information on the effects of temperature on hydrophobic solvation. Five model hydrophobes in SPC/E water give benchmark solvation entropies via Widom’s test-particle insertion method, and other methods and models are tested against these particle-insertion results. Entropies associated with distributions of tetrahedral order, of electric field, and of solvent dipole orientations are examined. We find these contributions are small compared to the benchmark particle-insertion entropy. Competitive with or better than other theories in accuracy, but with no free parameters, is the new estimate of the entropy contributed by correlations between dipole moments. Dipole correlations account for most of the hydrophobic solvation entropy for all models studied and capture the distinctive temperature dependence seen in thermodynamic and spectroscopic experiments. Entropies based on pair and many-body correlations in number density approach the correct magnitudes but fail to describe temperature and size dependences, respectively. Hydrogen-bond definitions and free energies that best reproduce entropies from simulations are reported, but it is difficult to choose one hydrogen bond model that fits a variety of experiments. The use of information theory, scaled-particle theory, and related methods is discussed briefly. Our results provide a test of the Frank-Evans hypothesis that the negative solvation entropy is due to structured water near the solute, complement the spectroscopic detection of that solvation structure by

  3. Review on the Modeling of Electrostatic MEMS

    Directory of Open Access Journals (Sweden)

    Wan-Chun Chuang

    2010-06-01

    Full Text Available Electrostatic-driven microelectromechanical systems devices, in most cases, consist of couplings of such energy domains as electromechanics, optical electricity, thermoelectricity, and electromagnetism. Their nonlinear working state makes their analysis complex and complicated. This article introduces the physical model of pull-in voltage, dynamic characteristic analysis, air damping effect, reliability, numerical modeling method, and application of electrostatic-driven MEMS devices.

  4. Maximum entropy PDF projection: A review

    Science.gov (United States)

    Baggenstoss, Paul M.

    2017-06-01

    We review maximum entropy (MaxEnt) PDF projection, a method with wide potential applications in statistical inference. The method constructs a sampling distribution for a high-dimensional vector x based on knowing the sampling distribution p(z) of a lower-dimensional feature z = T (x). Under mild conditions, the distribution p(x) having highest possible entropy among all distributions consistent with p(z) may be readily found. Furthermore, the MaxEnt p(x) may be sampled, making the approach useful in Monte Carlo methods. We review the theorem and present a case study in model order selection and classification for handwritten character recognition.

  5. Quantum key distribution with finite resources: Smooth Min entropy vs. Smooth Renyi entropy

    Energy Technology Data Exchange (ETDEWEB)

    Mertz, Markus; Abruzzo, Silvestre; Bratzik, Sylvia; Kampermann, Hermann; Bruss, Dagmar [Institut fuer Theoretische Physik III, Duesseldorf (Germany)

    2010-07-01

    We consider different entropy measures that play an important role in the analysis of the security of QKD with finite resources. The smooth min entropy leads to an optimal bound for the length of a secure key. Another bound on the secure key length was derived by using Renyi entropies. Unfortunately, it is very hard or even impossible to calculate these entropies for realistic QKD scenarios. To estimate the security rate it becomes important to find computable bounds on these entropies. Here, we compare a lower bound for the smooth min entropy with a bound using Renyi entropies. We compare these entropies for the six-state protocol with symmetric attacks.

  6. Applying Improved Multiscale Fuzzy Entropy for Feature Extraction of MI-EEG

    Directory of Open Access Journals (Sweden)

    Ming-ai Li

    2017-01-01

    Full Text Available Electroencephalography (EEG is considered the output of a brain and it is a bioelectrical signal with multiscale and nonlinear properties. Motor Imagery EEG (MI-EEG not only has a close correlation with the human imagination and movement intention but also contains a large amount of physiological or disease information. As a result, it has been fully studied in the field of rehabilitation. To correctly interpret and accurately extract the features of MI-EEG signals, many nonlinear dynamic methods based on entropy, such as Approximate Entropy (ApEn, Sample Entropy (SampEn, Fuzzy Entropy (FE, and Permutation Entropy (PE, have been proposed and exploited continuously in recent years. However, these entropy-based methods can only measure the complexity of MI-EEG based on a single scale and therefore fail to account for the multiscale property inherent in MI-EEG. To solve this problem, Multiscale Sample Entropy (MSE, Multiscale Permutation Entropy (MPE, and Multiscale Fuzzy Entropy (MFE are developed by introducing scale factor. However, MFE has not been widely used in analysis of MI-EEG, and the same parameter values are employed when the MFE method is used to calculate the fuzzy entropy values on multiple scales. Actually, each coarse-grained MI-EEG carries the characteristic information of the original signal on different scale factors. It is necessary to optimize MFE parameters to discover more feature information. In this paper, the parameters of MFE are optimized independently for each scale factor, and the improved MFE (IMFE is applied to the feature extraction of MI-EEG. Based on the event-related desynchronization (ERD/event-related synchronization (ERS phenomenon, IMFE features from multi channels are fused organically to construct the feature vector. Experiments are conducted on a public dataset by using Support Vector Machine (SVM as a classifier. The experiment results of 10-fold cross-validation show that the proposed method yields

  7. Development of an SU-8 MEMS process with two metal electrodes using amorphous silicon as a sacrificial material

    KAUST Repository

    Ramadan, Khaled S.

    2013-02-08

    This work presents an SU-8 surface micromachining process using amorphous silicon as a sacrificial material, which also incorporates two metal layers for electrical excitation. SU-8 is a photo-patternable polymer that is used as a structural layer for MEMS and microfluidic applications due to its mechanical properties, biocompatibility and low cost. Amorphous silicon is used as a sacrificial layer in MEMS applications because it can be deposited in large thicknesses, and can be released in a dry method using XeF2, which alleviates release-based stiction problems related to MEMS applications. In this work, an SU-8 MEMS process was developed using ;-Si as a sacrificial layer. Two conductive metal electrodes were integrated in this process to allow out-of-plane electrostatic actuation for applications like MEMS switches and variable capacitors. In order to facilitate more flexibility for MEMS designers, the process can fabricate dimples that can be conductive or nonconductive. Additionally, this SU-8 process can fabricate SU-8 MEMS structures of a single layer of two different thicknesses. Process parameters were optimized for two sets of thicknesses: thin (5-10 m) and thick (130 m). The process was tested fabricating MEMS switches, capacitors and thermal actuators. © 2013 IOP Publishing Ltd.

  8. On Measuring the Complexity of Networks: Kolmogorov Complexity versus Entropy

    Directory of Open Access Journals (Sweden)

    Mikołaj Morzy

    2017-01-01

    Full Text Available One of the most popular methods of estimating the complexity of networks is to measure the entropy of network invariants, such as adjacency matrices or degree sequences. Unfortunately, entropy and all entropy-based information-theoretic measures have several vulnerabilities. These measures neither are independent of a particular representation of the network nor can capture the properties of the generative process, which produces the network. Instead, we advocate the use of the algorithmic entropy as the basis for complexity definition for networks. Algorithmic entropy (also known as Kolmogorov complexity or K-complexity for short evaluates the complexity of the description required for a lossless recreation of the network. This measure is not affected by a particular choice of network features and it does not depend on the method of network representation. We perform experiments on Shannon entropy and K-complexity for gradually evolving networks. The results of these experiments point to K-complexity as the more robust and reliable measure of network complexity. The original contribution of the paper includes the introduction of several new entropy-deceiving networks and the empirical comparison of entropy and K-complexity as fundamental quantities for constructing complexity measures for networks.

  9. New dynamic silicon photonic components enabled by MEMS technology

    Science.gov (United States)

    Errando-Herranz, Carlos; Edinger, Pierre; Colangelo, Marco; Björk, Joel; Ahmed, Samy; Stemme, Göran; Niklaus, Frank; Gylfason, Kristinn B.

    2018-02-01

    Silicon photonics is the study and application of integrated optical systems which use silicon as an optical medium, usually by confining light in optical waveguides etched into the surface of silicon-on-insulator (SOI) wafers. The term microelectromechanical systems (MEMS) refers to the technology of mechanics on the microscale actuated by electrostatic actuators. Due to the low power requirements of electrostatic actuation, MEMS components are very power efficient, making them well suited for dense integration and mobile operation. MEMS components are conventionally also implemented in silicon, and MEMS sensors such as accelerometers, gyros, and microphones are now standard in every smartphone. By combining these two successful technologies, new active photonic components with extremely low power consumption can be made. We discuss our recent experimental work on tunable filters, tunable fiber-to-chip couplers, and dynamic waveguide dispersion tuning, enabled by the marriage of silicon MEMS and silicon photonics.

  10. Power Management of MEMS-Based Storage Devices for Mobile Systems

    NARCIS (Netherlands)

    Khatib, M.G.; Hartel, Pieter H.

    2008-01-01

    Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. MEMS-based storage devices should also be energy efficient for deployment in mobile systems. The problem is that MEMS-based storage devices are mechanical,

  11. RF MEMS

    Indian Academy of Sciences (India)

    At the bare die level the insertion loss, return loss and the isolation ... ing and packaging of a silicon on glass based RF MEMS switch fabricated using DRIE. ..... follows the power law based on the asperity deformation model given by Pattona & ... Surface mount style RF packages (SMX series 580465) from Startedge Corp.

  12. Micro-electro-mechanical systems (MEMS: Technology for the 21st century

    Directory of Open Access Journals (Sweden)

    Đakov Tatjana A.

    2014-01-01

    Full Text Available Micro-electro-mechanical systems (MEMS are miniturized devices that can sense the environment, process and analyze information, and respond with a variety of mechanical and electrical actuators. MEMS consists of mechanical elements, sensors, actuators, electrical and electronics devices on a common silicon substrate. Micro-electro-mechanical systems are becoming a vital technology for modern society. Some of the advantages of MEMS devices are: very small size, very low power consumption, low cost, easy to integrate into systems or modify, small thermal constant, high resistance to vibration, shock and radiation, batch fabricated in large arrays, improved thermal expansion tolerance. MEMS technology is increasingly penetrating into our lives and improving quality of life, similar to what we experienced in the microelectronics revolution. Commercial opportunities for MEMS are rapidly growing in broad application areas, including biomedical, telecommunication, security, entertainment, aerospace, and more in both the consumer and industrial sectors on a global scale. As a breakthrough technology, MEMS is building synergy between previously unrelated fields such as biology and microelectronics. Many new MEMS and nanotechnology applications will emerge, expanding beyond that which is currently identified or known. MEMS are definitely technology for 21st century.

  13. Entropy Generation Due to Natural Convection in a Partially Heated Cavity by Local RBF-DQ Method

    DEFF Research Database (Denmark)

    Soleimani, S.; Qajarjazi, A.; Bararnia, H.

    2011-01-01

    The Local Radial Basis Function-Differential Quadrature (RBF-DQ) method is applied to twodimensional incompressible Navier-Stokes equations in primitive form. Numerical results of heatlines and entropy generation due to heat transfer and fluid friction have been obtained for laminar natural...

  14. RF-MEMS capacitive switches with high reliability

    Science.gov (United States)

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  15. Transfer Entropy for Nonparametric Granger Causality Detection : An Evaluation of Different Resampling Methods

    NARCIS (Netherlands)

    Diks, C.; Fang, H.

    2017-01-01

    The information-theoretical concept transfer entropy is an ideal measure for detecting conditional independence, or Granger causality in a time series setting. The recent literature indeed witnesses an increased interest in applications of entropy-based tests in this direction. However, those tests

  16. Shannon information entropy in heavy-ion collisions

    Science.gov (United States)

    Ma, Chun-Wang; Ma, Yu-Gang

    2018-03-01

    The general idea of information entropy provided by C.E. Shannon "hangs over everything we do" and can be applied to a great variety of problems once the connection between a distribution and the quantities of interest is found. The Shannon information entropy essentially quantify the information of a quantity with its specific distribution, for which the information entropy based methods have been deeply developed in many scientific areas including physics. The dynamical properties of heavy-ion collisions (HICs) process make it difficult and complex to study the nuclear matter and its evolution, for which Shannon information entropy theory can provide new methods and observables to understand the physical phenomena both theoretically and experimentally. To better understand the processes of HICs, the main characteristics of typical models, including the quantum molecular dynamics models, thermodynamics models, and statistical models, etc., are briefly introduced. The typical applications of Shannon information theory in HICs are collected, which cover the chaotic behavior in branching process of hadron collisions, the liquid-gas phase transition in HICs, and the isobaric difference scaling phenomenon for intermediate mass fragments produced in HICs of neutron-rich systems. Even though the present applications in heavy-ion collision physics are still relatively simple, it would shed light on key questions we are seeking for. It is suggested to further develop the information entropy methods in nuclear reactions models, as well as to develop new analysis methods to study the properties of nuclear matters in HICs, especially the evolution of dynamics system.

  17. Development of an SU-8 MEMS process with two metal electrodes using amorphous silicon as a sacrificial material

    KAUST Repository

    Ramadan, Khaled S.; Nasr, Tarek Adel Hosny; Foulds, Ian G.

    2013-01-01

    method using XeF2, which alleviates release-based stiction problems related to MEMS applications. In this work, an SU-8 MEMS process was developed using ;-Si as a sacrificial layer. Two conductive metal electrodes were integrated in this process to allow

  18. Different grades MEMS accelerometers error characteristics

    Science.gov (United States)

    Pachwicewicz, M.; Weremczuk, J.

    2017-08-01

    The paper presents calibration effects of two different MEMS accelerometers of different price and quality grades and discusses different accelerometers errors types. The calibration for error determining is provided by reference centrifugal measurements. The design and measurement errors of the centrifuge are discussed as well. It is shown that error characteristics of the sensors are very different and it is not possible to use simple calibration methods presented in the literature in both cases.

  19. Application of the multi-objective cross-entropy method to the vehicle routing problem with soft time windows

    Directory of Open Access Journals (Sweden)

    C Hauman

    2014-06-01

    Full Text Available The vehicle routing problem with time windows is a widely studied problem with many real-world applications. The problem considered here entails the construction of routes that a number of identical vehicles travel to service different nodes within a certain time window. New benchmark problems with multi-objective features were recently suggested in the literature and the multi-objective optimisation cross-entropy method is applied to these problems to investigate the feasibility of the method and to determine and propose reference solutions for the benchmark problems. The application of the cross-entropy method to the multi-objective vehicle routing problem with soft time windows is investigated. The objectives that are evaluated include the minimisation of the total distance travelled, the number of vehicles and/or routes, the total waiting time and delay time of the vehicles and the makespan of a route.

  20. Fabrication of integrated metallic MEMS devices

    DEFF Research Database (Denmark)

    Yalcinkaya, Arda Deniz; Ravnkilde, Jan Tue; Hansen, Ole

    2002-01-01

    A simple and complementary metal oxide semiconductor (CMOS) compatible fabrication technique for microelectromechanical (MEMS) devices is presented. The fabrication technology makes use of electroplated metal layers. Among the fabricated devices, high quality factor microresonators are characteri......A simple and complementary metal oxide semiconductor (CMOS) compatible fabrication technique for microelectromechanical (MEMS) devices is presented. The fabrication technology makes use of electroplated metal layers. Among the fabricated devices, high quality factor microresonators...

  1. Frequency adjustable MEMS vibration energy harvester

    Science.gov (United States)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

    2016-10-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  2. Frequency adjustable MEMS vibration energy harvester

    International Nuclear Information System (INIS)

    Podder, P; Constantinou, P; Roy, S; Amann, A

    2016-01-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

  3. Deep coupling of star tracker and MEMS-gyro data under highly dynamic and long exposure conditions

    International Nuclear Information System (INIS)

    Sun, Ting; Xing, Fei; You, Zheng; Wang, Xiaochu; Li, Bin

    2014-01-01

    Star trackers and gyroscopes are the two most widely used attitude measurement devices in spacecrafts. The star tracker is supposed to have the highest accuracy in stable conditions among different types of attitude measurement devices. In general, to detect faint stars and reduce the size of the star tracker, a method with long exposure time method is usually used. Thus, under dynamic conditions, smearing of the star image may appear and result in decreased accuracy or even failed extraction of the star spot. This may cause inaccuracies in attitude measurement. Gyros have relatively good dynamic performance and are usually used in combination with star trackers. However, current combination methods focus mainly on the data fusion of the output attitude data levels, which are inadequate for utilizing and processing internal blurred star image information. A method for tracking deep coupling stars and MEMS-gyro data is proposed in this work. The method achieves deep fusion at the star image level. First, dynamic star image processing is performed based on the angular velocity information of the MEMS-gyro. Signal-to-noise ratio (SNR) of the star spot could be improved, and extraction is achieved more effectively. Then, a prediction model for optimal estimation of the star spot position is obtained through the MEMS-gyro, and an extended Kalman filter is introduced. Meanwhile, the MEMS-gyro drift can be estimated and compensated though the proposed method. These enable the star tracker to achieve high star centroid determination accuracy under dynamic conditions. The MEMS-gyro drift can be corrected even when attitude data of the star tracker are unable to be solved and only one navigation star is captured in the field of view. Laboratory experiments were performed to verify the effectiveness of the proposed method and the whole system. (paper)

  4. The entropy of the life table: A reappraisal.

    Science.gov (United States)

    Fernandez, Oscar E; Beltrán-Sánchez, Hiram

    2015-09-01

    The life table entropy provides useful information for understanding improvements in mortality and survival in a population. In this paper we take a closer look at the life table entropy and use advanced mathematical methods to provide additional insights for understanding how it relates to changes in mortality and survival. By studying the entropy (H) as a functional, we show that changes in the entropy depend on both the relative change in life expectancy lost due to death (e(†)) and in life expectancy at birth (e0). We also show that changes in the entropy can be further linked to improvements in premature and older deaths. We illustrate our methods with empirical data from Latin American countries, which suggests that at high mortality levels declines in H (which are associated with survival increases) linked with larger improvements in e0, whereas at low mortality levels e(†) made larger contributions to H. We additionally show that among countries with low mortality level, contributions of e(†) to changes in the life table entropy resulted from averting early deaths. These findings indicate that future increases in overall survival in low mortality countries will likely result from improvements in e(†). Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Electron density distribution in Si and Ge using multipole, maximum ...

    Indian Academy of Sciences (India)

    Si and Ge has been studied using multipole, maximum entropy method (MEM) and ... and electron density distribution using the currently available versatile ..... data should be subjected to maximum possible utility for the characterization of.

  6. Entropy of black holes with multiple horizons

    Science.gov (United States)

    He, Yun; Ma, Meng-Sen; Zhao, Ren

    2018-05-01

    We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and "quintessence horizon" for the black holes surrounded by quintessence). Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

  7. Text mining by Tsallis entropy

    Science.gov (United States)

    Jamaati, Maryam; Mehri, Ali

    2018-01-01

    Long-range correlations between the elements of natural languages enable them to convey very complex information. Complex structure of human language, as a manifestation of natural languages, motivates us to apply nonextensive statistical mechanics in text mining. Tsallis entropy appropriately ranks the terms' relevance to document subject, taking advantage of their spatial correlation length. We apply this statistical concept as a new powerful word ranking metric in order to extract keywords of a single document. We carry out an experimental evaluation, which shows capability of the presented method in keyword extraction. We find that, Tsallis entropy has reliable word ranking performance, at the same level of the best previous ranking methods.

  8. Self-Similar Solutions of Rényi’s Entropy and the Concavity of Its Entropy Power

    Directory of Open Access Journals (Sweden)

    Agapitos N. Hatzinikitas

    2015-08-01

    Full Text Available We study the class of self-similar probability density functions with finite mean and variance, which maximize Rényi’s entropy. The investigation is restricted in the Schwartz space S(Rd and in the space of l-differentiable compactly supported functions Clc (Rd. Interestingly, the solutions of this optimization problem do not coincide with the solutions of the usual porous medium equation with a Dirac point source, as occurs in the optimization of Shannon’s entropy. We also study the concavity of the entropy power in Rd with respect to time using two different methods. The first one takes advantage of the solutions determined earlier, while the second one is based on a setting that could be used for Riemannian manifolds.

  9. Parametric Bayesian Estimation of Differential Entropy and Relative Entropy

    Directory of Open Access Journals (Sweden)

    Maya Gupta

    2010-04-01

    Full Text Available Given iid samples drawn from a distribution with known parametric form, we propose the minimization of expected Bregman divergence to form Bayesian estimates of differential entropy and relative entropy, and derive such estimators for the uniform, Gaussian, Wishart, and inverse Wishart distributions. Additionally, formulas are given for a log gamma Bregman divergence and the differential entropy and relative entropy for the Wishart and inverse Wishart. The results, as always with Bayesian estimates, depend on the accuracy of the prior parameters, but example simulations show that the performance can be substantially improved compared to maximum likelihood or state-of-the-art nonparametric estimators.

  10. Nonlinear Adaptive Filter for MEMS Gyro Error Cancellation

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal biases are the dominate error in low-cost low-power small MEMS gyros. CubeSats often can't afford the power/mass to put a heater on their MEMS gyros and...

  11. Entropy? Honest!

    Directory of Open Access Journals (Sweden)

    Tommaso Toffoli

    2016-06-01

    Full Text Available Here we deconstruct, and then in a reasoned way reconstruct, the concept of “entropy of a system”, paying particular attention to where the randomness may be coming from. We start with the core concept of entropy as a count associated with a description; this count (traditionally expressed in logarithmic form for a number of good reasons is in essence the number of possibilities—specific instances or “scenarios”—that match that description. Very natural (and virtually inescapable generalizations of the idea of description are the probability distribution and its quantum mechanical counterpart, the density operator. We track the process of dynamically updating entropy as a system evolves. Three factors may cause entropy to change: (1 the system’s internal dynamics; (2 unsolicited external influences on it; and (3 the approximations one has to make when one tries to predict the system’s future state. The latter task is usually hampered by hard-to-quantify aspects of the original description, limited data storage and processing resource, and possibly algorithmic inadequacy. Factors 2 and 3 introduce randomness—often huge amounts of it—into one’s predictions and accordingly degrade them. When forecasting, as long as the entropy bookkeping is conducted in an honest fashion, this degradation will always lead to an entropy increase. To clarify the above point we introduce the notion of honest entropy, which coalesces much of what is of course already done, often tacitly, in responsible entropy-bookkeping practice. This notion—we believe—will help to fill an expressivity gap in scientific discourse. With its help, we shall prove that any dynamical system—not just our physical universe—strictly obeys Clausius’s original formulation of the second law of thermodynamics if and only if it is invertible. Thus this law is a tautological property of invertible systems!

  12. Waveguide-Integrated MEMS Concepts for Tunable Millimeter-Wave Systems

    OpenAIRE

    Baghchehsaraei, Zargham

    2014-01-01

    This thesis presents two families of novel waveguide-integrated components based on millimeter-wave microelectromechanical systems (MEMS) for reconfigurable systems. The first group comprises V-band (50–75 GHz) and W-band (75–110 GHz) waveguide switches and switchable irises, and their application as switchable cavity resonators, and tunable bandpass filters implemented by integration of novel MEMS-reconfigurable surfaces into a rectangular waveguide. The second category comprises MEMS-based ...

  13. Quantum statistical entropy corresponding to cosmic horizon in five-dimensional spacetime

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The generalized uncertainty relation is introduced to calculate the quantum statis-tical entropy corresponding to cosmic horizon. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is no divergent logarithmic term in the original brick-wall method. And it is obtained that the quantum statistical en-tropy corresponding to cosmic horizon is proportional to the area of the horizon. Further it is shown that the entropy corresponding to cosmic horizon is the entropy of quantum state on the surface of horizon. The black hole’s entropy is the intrinsic property of the black hole. The entropy is a quantum effect. In our calculation, by using the quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of five-dimensional spacetime. We provide a way to study the quantum statistical entropy corresponding to cosmic horizon in the higher-dimensional spacetime.

  14. 2D Tsallis Entropy for Image Segmentation Based on Modified Chaotic Bat Algorithm

    Directory of Open Access Journals (Sweden)

    Zhiwei Ye

    2018-03-01

    Full Text Available Image segmentation is a significant step in image analysis and computer vision. Many entropy based approaches have been presented in this topic; among them, Tsallis entropy is one of the best performing methods. However, 1D Tsallis entropy does not consider make use of the spatial correlation information within the neighborhood results might be ruined by noise. Therefore, 2D Tsallis entropy is proposed to solve the problem, and results are compared with 1D Fisher, 1D maximum entropy, 1D cross entropy, 1D Tsallis entropy, fuzzy entropy, 2D Fisher, 2D maximum entropy and 2D cross entropy. On the other hand, due to the existence of huge computational costs, meta-heuristics algorithms like genetic algorithm (GA, particle swarm optimization (PSO, ant colony optimization algorithm (ACO and differential evolution algorithm (DE are used to accelerate the 2D Tsallis entropy thresholding method. In this paper, considering 2D Tsallis entropy as a constrained optimization problem, the optimal thresholds are acquired by maximizing the objective function using a modified chaotic Bat algorithm (MCBA. The proposed algorithm has been tested on some actual and infrared images. The results are compared with that of PSO, GA, ACO and DE and demonstrate that the proposed method outperforms other approaches involved in the paper, which is a feasible and effective option for image segmentation.

  15. Monitoring System for Slope Stability under Rainfall by using MEMS Acceleration Sensor IC tags

    International Nuclear Information System (INIS)

    Murakami, S; Dairaku, A; Komine, H; Saito, O; Sakai, N; Isizawa, T; Maruyama, I

    2013-01-01

    Real-time warning system for slope failure under rainfall is available to disaster prevention and mitigation. Monitoring of multi-point and wireless measurements is effective because it is difficult to conclude the most dangerous part in a slope. The purpose of this study is to propose a method of monitoring system with multi-point and wireless measurements for a slope stability using MEMS acceleration sensor IC tags. MEMS acceleration sensor IC tag is an acceleration sensor microminiaturized by a technology of Micro Electro Mechanical Systems on board IC tag. Especially, low cost of the sensor will yield to the realization of the system. In order to investigate the applicability of the proposed system, a large-scale model test of artificial slope subjected to rainfall has been performed. MEMS acceleration sensor IC tags has been located on the slope and ground acceleration caused by forced vibration has been measured until the model slope collapses. The experimental results show that the MEMS acceleration sensor IC tag is comfortably available under rainfall, the characteristics of ground accelerations varies with changing the condition of the slope subjected to rainfall, and the proposed method can be applied to a real-time monitoring system for slope failure under rainfall.

  16. Infinite Shannon entropy

    International Nuclear Information System (INIS)

    Baccetti, Valentina; Visser, Matt

    2013-01-01

    Even if a probability distribution is properly normalizable, its associated Shannon (or von Neumann) entropy can easily be infinite. We carefully analyze conditions under which this phenomenon can occur. Roughly speaking, this happens when arbitrarily small amounts of probability are dispersed into an infinite number of states; we shall quantify this observation and make it precise. We develop several particularly simple, elementary, and useful bounds, and also provide some asymptotic estimates, leading to necessary and sufficient conditions for the occurrence of infinite Shannon entropy. We go to some effort to keep technical computations as simple and conceptually clear as possible. In particular, we shall see that large entropies cannot be localized in state space; large entropies can only be supported on an exponentially large number of states. We are for the time being interested in single-channel Shannon entropy in the information theoretic sense, not entropy in a stochastic field theory or quantum field theory defined over some configuration space, on the grounds that this simple problem is a necessary precursor to understanding infinite entropy in a field theoretic context. (paper)

  17. Charmonium correlators and spectral functions at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ding,H.T.; Kaczmarek, O.; Karsch, F.; Satz, H.

    2008-09-01

    We present an operational approach to address the in-medium behavior of charmonium and analyze the reliability of maximum entropy method (MEM). We study the dependences of the ratio of correlators to the reconstructed one and the free one on the resonance's width and the continuum's threshold. Furthermore, we discuss the issue of the default model dependence of the spectral function obtained from MEM.

  18. Operational characterization of CSFH MEMS technology based hinges

    Science.gov (United States)

    Crescenzi, Rocco; Balucani, Marco; Belfiore, Nicola Pio

    2018-05-01

    Progress in MEMS technology continuously stimulates new developments in the mechanical structure of micro systems, such as, for example, the concept of so-called CSFH (conjugate surfaces flexural hinge), which makes it possible, simultaneously, to minimize the internal stresses and to increase motion range and robustness. Such a hinge may be actuated by means of a rotary comb-drive, provided that a proper set of simulations and tests are capable to assess its feasibility. In this paper, a CSFH has been analyzed with both theoretical and finite element (FEM) methods, in order to obtain the relation between voltage and generated torque. The FEM model considers also the fringe effect on the comb drive finger. Electromechanical couple-field analysis is performed by means of both direct and load transfer methods. Experimental tests have been also performed on a CSFH embedded in a MEMS prototype, which has been fabricated starting from a SOI wafer and using D-RIE (deep reactive ion etching). Results showed that CSFH performs better than linear flexure hinges in terms of larger rotations and less stress for given applied voltage.

  19. MEMS (Micro-Electro-Mechanical Systems) for Automotive and Consumer Electronics

    Science.gov (United States)

    Marek, Jiri; Gómez, Udo-Martin

    MEMS sensors gained over the last two decades an impressive width of applications: (a) ESP: A car is skidding and stabilizes itself without driver intervention (b) Free-fall detection: A laptop falls to the floor and protects the hard drive by parking the read/write drive head automatically before impact. (c) Airbag: An airbag fires before the driver/occupant involved in an impending automotive crash impacts the steering wheel, thereby significantly reducing physical injury risk. MEMS sensors are sensing the environmental conditions and are giving input to electronic control systems. These crucial MEMS sensors are making system reactions to human needs more intelligent, precise, and at much faster reaction rates than humanly possible. Important prerequisites for the success of sensors are their size, functionality, power consumption, and costs. This technical progress in sensor development is realized by micro-machining. The development of these processes was the breakthrough to industrial mass-production for micro-electro-mechanical systems (MEMS). Besides leading-edge micromechanical processes, innovative and robust ASIC designs, thorough simulations of the electrical and mechanical behaviour, a deep understanding of the interactions (mainly over temperature and lifetime) of the package and the mechanical structures are needed. This was achieved over the last 20 years by intense and successful development activities combined with the experience of volume production of billions of sensors. This chapter gives an overview of current MEMS technology, its applications and the market share. The MEMS processes are described, and the challenges of MEMS, compared to standard IC fabrication, are discussed. The evolution of MEMS requirements is presented, and a short survey of MEMS applications is shown. Concepts of newest inertial sensors for ESP-systems are given with an emphasis on the design concepts of the sensing element and the evaluation circuit for achieving

  20. Relation Entropy and Transferable Entropy Think of Aggregation on Group Decision Making

    Institute of Scientific and Technical Information of China (English)

    CHENG Qi-yue; QIU Wan-hua; LIU Xiao-feng

    2002-01-01

    In this paper, aggregation question based on group decision making and a single decision making is studied. The theory of entropy is applied to the sets pair analysis. The system of relation entropy and the transferable entropy notion are put. The character is studied. An potential by the relation entropy and transferable entropy are defined. It is the consistency measure on the group between a single decision making. We gained a new aggregation effective definition on the group misjudge.

  1. Some Design Considerations on the Electrostatically Actuated Fixed-Fixed End Type MEMS Switches

    International Nuclear Information System (INIS)

    Sadeghian, Hamed; Rezazadeh, Ghader; Sani, Ebrahim Abbaspour

    2006-01-01

    The nonlinear electrostatic pull-in behaviour of MEMS Switches in micro-electromechanical systems (MEMS) is investigated in this article. We used the distributed model when the electrostatic pressure didn't apply at the whole of the beam and applied only in the mid-part of the beam. In this part the electrostatic area is different from two other parts. The model uses Euler-Bernoulli beam theory for fixed-fixed end type beams. The finite difference method was used to solve the nonlinear equation. The proposed model includes the fringing effects of the electrical field, residual stress and varying electrostatic area effects. The numerical results reveal that the profile deflection of the MEMS Switch may not only influence the distribution of the electrostatic force but also considerably change the nonlinear pull-in voltage

  2. Driver Fatigue Detection System Using Electroencephalography Signals Based on Combined Entropy Features

    Directory of Open Access Journals (Sweden)

    Zhendong Mu

    2017-02-01

    Full Text Available Driver fatigue has become one of the major causes of traffic accidents, and is a complicated physiological process. However, there is no effective method to detect driving fatigue. Electroencephalography (EEG signals are complex, unstable, and non-linear; non-linear analysis methods, such as entropy, maybe more appropriate. This study evaluates a combined entropy-based processing method of EEG data to detect driver fatigue. In this paper, 12 subjects were selected to take part in an experiment, obeying driving training in a virtual environment under the instruction of the operator. Four types of enthrones (spectrum entropy, approximate entropy, sample entropy and fuzzy entropy were used to extract features for the purpose of driver fatigue detection. Electrode selection process and a support vector machine (SVM classification algorithm were also proposed. The average recognition accuracy was 98.75%. Retrospective analysis of the EEG showed that the extracted features from electrodes T5, TP7, TP8 and FP1 may yield better performance. SVM classification algorithm using radial basis function as kernel function obtained better results. A combined entropy-based method demonstrates good classification performance for studying driver fatigue detection.

  3. Effect of various concentrations of Minimal Essential Medium vitamins (MEM vitamins on development of

    Directory of Open Access Journals (Sweden)

    Hamed Karami Shabankareh

    2012-01-01

    Full Text Available Background: Improvements in culture media formulations have led to an increasein the ability of sheep embryo in culture throughout the preimplantation period.Objective: This study was carried out to evaluate the effects of variousconcentrations of MEM vitamins during in vitro maturation of sheep oocytes andsubsequent embryo development.Materials and Methods: Sheep ovaries were collected from a slaughterhouse andtransported to the laboratory. Oocytes were matured in SOF medium supplementedwith, eCG, hCG and EGF in various concentrations of MEM vitamins (control, 0.5,1 and 1.5 for 24h. The cumulus oocyte compelex (COCs were co-incubated withepididymal spermatozoa of post mortem rams in synthetic oviduct fluid fertilization(SOFF medium with 10% heat inactivated estrous sheep serum for 18h. Embryoswere cultured in synthetic oviduct fluid culture 1 (SOFC1 medium for 48h followedby cultured in synthetic oviduct fluid culture 2 (SOFC2 medium for six days.Results: Addition of 0.5 and 1  MEM vitamins significantly increased (P< 0.05overall blastocyst development (21.62% and 22.33%; respectively compared with1.5MEM vitamins (15.59%, but there was no difference between control, 0.5 and1MEM vitamins in the percentage of embryos successfully developing to theblastocyst stage (19.50%, 21.62% and 22.33% respectively.Conclusion: It seems that addition of 1.5  of MEM vitamins has detrimental effecton blastocyst rate.

  4. Modularly Integrated MEMS Technology

    National Research Council Canada - National Science Library

    Eyoum, Marie-Angie N

    2006-01-01

    Process design, development and integration to fabricate reliable MEMS devices on top of VLSI-CMOS electronics without damaging the underlying circuitry have been investigated throughout this dissertation...

  5. MEMS for pico- to micro-satellites

    OpenAIRE

    Shea, Herbert

    2009-01-01

    MEMS sensors, actuators, and sub-systems can enable an important reduction in the size and mass of spacecrafts, first by replacing larger and heavier components, then by replacing entire subsystems, and finally by enabling the microfabrication of highly integrated picosats. Very small satellites (1 to 100 kg) stand to benefit the most from MEMS technologies. These small satellites are typically used for science or technology demonstration missions, with higher risk tolerance than multi-ton te...

  6. Modeling, Calibration and Control for Extreme-Precision MEMS Deformable Mirrors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Iris AO will develop electromechanical models and actuator calibration methods to enable open-loop control of MEMS deformable mirrors (DMs) with unprecedented...

  7. Biogeography-inspired multiobjective optimization for helping MEMS synthesis

    Directory of Open Access Journals (Sweden)

    Di Barba Paolo

    2017-09-01

    Full Text Available The aim of the paper is to assess the applicability of a multi-objective biogeography-based optimisation algorithm in MEMS synthesis. In order to test the performances of the proposed method in this research field, the optimal shape design of an electrostatic micromotor, and two different electro-thermo-elastic microactuators are considered as the case studies.

  8. Acoustic resonance in MEMS scale cylindrical tubes with side branches

    Science.gov (United States)

    Schill, John F.; Holthoff, Ellen L.; Pellegrino, Paul M.; Marcus, Logan S.

    2014-05-01

    Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace gas detection. This method routinely exhibits detection limits at the parts-per-million (ppm) or parts-per-billion (ppb) level for gaseous samples. PAS also possesses favorable detection characteristics when the system dimensions are scaled to a microelectromechanical system (MEMS) design. One of the central issues related to sensor miniaturization is optimization of the photoacoustic cell geometry, especially in relationship to high acoustical amplification and reduced system noise. Previous work relied on a multiphysics approach to analyze the resonance structures of the MEMS scale photo acoustic cell. This technique was unable to provide an accurate model of the acoustic structure. In this paper we describe a method that relies on techniques developed from musical instrument theory and electronic transmission line matrix methods to describe cylindrical acoustic resonant cells with side branches of various configurations. Experimental results are presented that demonstrate the ease and accuracy of this method. All experimental results were within 2% of those predicted by this theory.

  9. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  10. On the Stiction of MEMS Materials

    DEFF Research Database (Denmark)

    Zhuang, Yanxin; Menon, Aric Kumaran

    2005-01-01

    energies and stiction of commonly used MEMS materials by contact angle measurements and atomic force microscopy (AFM). Dispersive and polar components of surface energies are calculated by Owens-Wendt-Rabel-Kaelble method. Silicon and silicon-related materials have higher polar surface energies than SU-8...... been shown that the materials with higher surface energy have higher sticton/adhesion forces. The topography of surface influences the contact angle and stiction, and is also discussed in the paper....

  11. Entropy of black holes with multiple horizons

    Directory of Open Access Journals (Sweden)

    Yun He

    2018-05-01

    Full Text Available We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and “quintessence horizon” for the black holes surrounded by quintessence. Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

  12. Entropy and heat generation of lithium cells/batteries

    International Nuclear Information System (INIS)

    Wang Songrui

    2016-01-01

    The methods and techniques commonly used in investigating the change of entropy and heat generation in Li cells/batteries are introduced, as are the measurements, calculations and purposes. The changes of entropy and heat generation are concomitant with the use of Li cells/batteries. In order to improve the management and the application of Li cells/batteries, especially for large scale power batteries, the quantitative investigations of the change of entropy and heat generating are necessary. (topical review)

  13. MEMS Solar Generators

    OpenAIRE

    Grbovic, Dragoslav; Osswald, Sebastian

    2011-01-01

    Approved for public release; distribution is unlimited Using MEMS bimaterial structures to build highly efficient solar energy generators. This is a novel approach that utilizes developments in the area of bimaterial sensors and applies them in the field of solar energy harvesting.

  14. Identification of a Threshold Value for the DEMATEL Method: Using the Maximum Mean De-Entropy Algorithm

    Science.gov (United States)

    Chung-Wei, Li; Gwo-Hshiung, Tzeng

    To deal with complex problems, structuring them through graphical representations and analyzing causal influences can aid in illuminating complex issues, systems, or concepts. The DEMATEL method is a methodology which can be used for researching and solving complicated and intertwined problem groups. The end product of the DEMATEL process is a visual representation—the impact-relations map—by which respondents organize their own actions in the world. The applicability of the DEMATEL method is widespread, ranging from analyzing world problematique decision making to industrial planning. The most important property of the DEMATEL method used in the multi-criteria decision making (MCDM) field is to construct interrelations between criteria. In order to obtain a suitable impact-relations map, an appropriate threshold value is needed to obtain adequate information for further analysis and decision-making. In this paper, we propose a method based on the entropy approach, the maximum mean de-entropy algorithm, to achieve this purpose. Using real cases to find the interrelationships between the criteria for evaluating effects in E-learning programs as an examples, we will compare the results obtained from the respondents and from our method, and discuss that the different impact-relations maps from these two methods.

  15. Digital Image Stabilization Method Based on Variational Mode Decomposition and Relative Entropy

    Directory of Open Access Journals (Sweden)

    Duo Hao

    2017-11-01

    Full Text Available Cameras mounted on vehicles frequently suffer from image shake due to the vehicles’ motions. To remove jitter motions and preserve intentional motions, a hybrid digital image stabilization method is proposed that uses variational mode decomposition (VMD and relative entropy (RE. In this paper, the global motion vector (GMV is initially decomposed into several narrow-banded modes by VMD. REs, which exhibit the difference of probability distribution between two modes, are then calculated to identify the intentional and jitter motion modes. Finally, the summation of the jitter motion modes constitutes jitter motions, whereas the subtraction of the resulting sum from the GMV represents the intentional motions. The proposed stabilization method is compared with several known methods, namely, medium filter (MF, Kalman filter (KF, wavelet decomposition (MD method, empirical mode decomposition (EMD-based method, and enhanced EMD-based method, to evaluate stabilization performance. Experimental results show that the proposed method outperforms the other stabilization methods.

  16. Machine Selection in A Dairy Product Company with Entropy and SAW Method Integration

    Directory of Open Access Journals (Sweden)

    Aşkın Özdağoğlu

    2017-07-01

    Full Text Available Machine selection is an important and difficult process for the firms, and its results may generate more problems than anticipated. In order to find the best alternative, managers should define the requirements of the factory and determine the necessary criteria. On the other hand, the decision making criteria in order to choose the right equipment may vary according to the type of the manufacturing facility, market requirements, and consumer assigned criteria. This study aims to find the best machine alternative  among  the three machine offerings according to twelve evaluation criteria by integrating entropy method with SAW method.

  17. Path length entropy analysis of diastolic heart sounds.

    Science.gov (United States)

    Griffel, Benjamin; Zia, Mohammad K; Fridman, Vladamir; Saponieri, Cesare; Semmlow, John L

    2013-09-01

    Early detection of coronary artery disease (CAD) using the acoustic approach, a noninvasive and cost-effective method, would greatly improve the outcome of CAD patients. To detect CAD, we analyze diastolic sounds for possible CAD murmurs. We observed diastolic sounds to exhibit 1/f structure and developed a new method, path length entropy (PLE) and a scaled version (SPLE), to characterize this structure to improve CAD detection. We compare SPLE results to Hurst exponent, Sample entropy and Multiscale entropy for distinguishing between normal and CAD patients. SPLE achieved a sensitivity-specificity of 80%-81%, the best of the tested methods. However, PLE and SPLE are not sufficient to prove nonlinearity, and evaluation using surrogate data suggests that our cardiovascular sound recordings do not contain significant nonlinear properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Entropy-Based Video Steganalysis of Motion Vectors

    Directory of Open Access Journals (Sweden)

    Elaheh Sadat Sadat

    2018-04-01

    Full Text Available In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and the irregularity of each block increases the precision of the final video classification into cover and stego classes.

  19. Application of the maximum entropy method to profile analysis

    International Nuclear Information System (INIS)

    Armstrong, N.; Kalceff, W.; Cline, J.P.

    1999-01-01

    Full text: A maximum entropy (MaxEnt) method for analysing crystallite size- and strain-induced x-ray profile broadening is presented. This method treats the problems of determining the specimen profile, crystallite size distribution, and strain distribution in a general way by considering them as inverse problems. A common difficulty faced by many experimenters is their inability to determine a well-conditioned solution of the integral equation, which preserves the positivity of the profile or distribution. We show that the MaxEnt method overcomes this problem, while also enabling a priori information, in the form of a model, to be introduced into it. Additionally, we demonstrate that the method is fully quantitative, in that uncertainties in the solution profile or solution distribution can be determined and used in subsequent calculations, including mean particle sizes and rms strain. An outline of the MaxEnt method is presented for the specific problems of determining the specimen profile and crystallite or strain distributions for the correspondingly broadened profiles. This approach offers an alternative to standard methods such as those of Williamson-Hall and Warren-Averbach. An application of the MaxEnt method is demonstrated in the analysis of alumina size-broadened diffraction data (from NIST, Gaithersburg). It is used to determine the specimen profile and column-length distribution of the scattering domains. Finally, these results are compared with the corresponding Williamson-Hall and Warren-Averbach analyses. Copyright (1999) Australian X-ray Analytical Association Inc

  20. Characterizing time-dependent mechanics in metallic MEMS

    Directory of Open Access Journals (Sweden)

    Geers M.G.D.

    2010-06-01

    Full Text Available Experiments for characterization of time-dependent material properties in free-standing metallic microelectromechanical system (MEMS pose challenges: e.g. fabrication and handling (sub-μm sized specimens, control and measurement of sub-μN loads and sub-μm displacements over long periods and various temperatures [1]. A variety of experimental setups have been reported each having their pros and cons. One example is a micro-tensile tester with an ingenious electro-static specimen gripping system [2] aiding simple specimen design giving good results at μN and sub-μm levels, but without in-situ full-field observations. Other progressive examples assimilate the specimen, MEMS actuators and load cells on a single chip [3,4] yielding significant results at nN and nm levels with in-situ TEM/SEM observability, though not without complications: complex load actuator/sensor calibration per chip, measures to reduce fabrication failure and unfeasible cofabrication on wafers with commercial metallic MEMS. This work aims to overcome these drawbacks by developing experimental methods with high sensitivity, precision and in-situ full-field observation capabilities. Moreover, these should be applicable to simple free-standing metallic MEMS that can be co-fabricated with commercial devices. These methods will then serve in systematic studies into size-effects in time-dependent material properties. First a numeric-experimental method is developed. It characterizes bending deformation of onwafer μm-sized aluminum cantilevers. A specially designed micro-clamp is used to mechanically apply a constant precise deflection of the beam (zres <50 nm for a prolonged period, see fig. 1. After this period, the deflection by the micro-clamp is removed. Full-field height maps with the ensuing deformation are measured over time with confocal optical profilometry (COP. This yields the tip deflection as function of time with ~3 nm precision, see fig.2. To extract material

  1. Optical MEMS for earth observation payloads

    Science.gov (United States)

    Rodrigues, B.; Lobb, D. R.; Freire, M.

    2017-11-01

    An ESA study has been taken by Lusospace Ltd and Surrey Satellite Techonoly Ltd (SSTL) into the use of optical Micro Eletro-Mechanical Systems (MEMS) for earth Observation. A review and analysis was undertaken of the Micro-Optical Electro-Mechanical Systems (MOEMS) available in the market with potential application in systems for Earth Observation. A summary of this review will be presented. Following the review two space-instrument design concepts were selected for more detailed analysis. The first was the use of a MEMS device to remove cloud from Earth images. The concept is potentially of interest for any mission using imaging spectrometers. A spectrometer concept was selected and detailed design aspects and benefits evaluated. The second concept developed uses MEMS devices to control the width of entrance slits of spectrometers, to provide variable spectral resolution. This paper will present a summary of the results of the study.

  2. MEMS applications in space exploration

    Science.gov (United States)

    Tang, William C.

    1997-09-01

    Space exploration in the coming century will emphasize cost effectiveness and highly focused mission objectives, which will result in frequent multiple missions that broaden the scope of space science and to validate new technologies on a timely basis. MEMS is one of the key enabling technology to create cost-effective, ultra-miniaturized, robust, and functionally focused spacecraft for both robotic and human exploration programs. Examples of MEMS devices at various stages of development include microgyroscope, microseismometer, microhygrometer, quadrupole mass spectrometer, and micropropulsion engine. These devices, when proven successful, will serve as models for developing components and systems for new-millennium spacecraft.

  3. Three faces of entropy for complex systems: Information, thermodynamics, and the maximum entropy principle

    Science.gov (United States)

    Thurner, Stefan; Corominas-Murtra, Bernat; Hanel, Rudolf

    2017-09-01

    There are at least three distinct ways to conceptualize entropy: entropy as an extensive thermodynamic quantity of physical systems (Clausius, Boltzmann, Gibbs), entropy as a measure for information production of ergodic sources (Shannon), and entropy as a means for statistical inference on multinomial processes (Jaynes maximum entropy principle). Even though these notions represent fundamentally different concepts, the functional form of the entropy for thermodynamic systems in equilibrium, for ergodic sources in information theory, and for independent sampling processes in statistical systems, is degenerate, H (p ) =-∑ipilogpi . For many complex systems, which are typically history-dependent, nonergodic, and nonmultinomial, this is no longer the case. Here we show that for such processes, the three entropy concepts lead to different functional forms of entropy, which we will refer to as SEXT for extensive entropy, SIT for the source information rate in information theory, and SMEP for the entropy functional that appears in the so-called maximum entropy principle, which characterizes the most likely observable distribution functions of a system. We explicitly compute these three entropy functionals for three concrete examples: for Pólya urn processes, which are simple self-reinforcing processes, for sample-space-reducing (SSR) processes, which are simple history dependent processes that are associated with power-law statistics, and finally for multinomial mixture processes.

  4. Statistical properties of entropy production derived from fluctuation theorems

    International Nuclear Information System (INIS)

    Merhav, Neri; Kafri, Yariv

    2010-01-01

    Several implications of well-known fluctuation theorems, on the statistical properties of entropy production, are studied using various approaches. We begin by deriving a tight lower bound on the variance of the entropy production for a given mean of this random variable. It is shown that the Evans–Searles fluctuation theorem alone imposes a significant lower bound on the variance only when the mean entropy production is very small. It is then nonetheless demonstrated that upon incorporating additional information concerning the entropy production, this lower bound can be significantly improved, so as to capture extensivity properties. Another important aspect of the fluctuation properties of the entropy production is the relationship between the mean and the variance, on the one hand, and the probability of the event where the entropy production is negative, on the other hand. Accordingly, we derive upper and lower bounds on this probability in terms of the mean and the variance. These bounds are tighter than previous bounds that can be found in the literature. Moreover, they are tight in the sense that there exist probability distributions, satisfying the Evans–Searles fluctuation theorem, that achieve them with equality. Finally, we present a general method for generating a wide class of inequalities that must be satisfied by the entropy production. We use this method to derive several new inequalities that go beyond the standard derivation of the second law

  5. Maximum entropy deconvolution of low count nuclear medicine images

    International Nuclear Information System (INIS)

    McGrath, D.M.

    1998-12-01

    Maximum entropy is applied to the problem of deconvolving nuclear medicine images, with special consideration for very low count data. The physics of the formation of scintigraphic images is described, illustrating the phenomena which degrade planar estimates of the tracer distribution. Various techniques which are used to restore these images are reviewed, outlining the relative merits of each. The development and theoretical justification of maximum entropy as an image processing technique is discussed. Maximum entropy is then applied to the problem of planar deconvolution, highlighting the question of the choice of error parameters for low count data. A novel iterative version of the algorithm is suggested which allows the errors to be estimated from the predicted Poisson mean values. This method is shown to produce the exact results predicted by combining Poisson statistics and a Bayesian interpretation of the maximum entropy approach. A facility for total count preservation has also been incorporated, leading to improved quantification. In order to evaluate this iterative maximum entropy technique, two comparable methods, Wiener filtering and a novel Bayesian maximum likelihood expectation maximisation technique, were implemented. The comparison of results obtained indicated that this maximum entropy approach may produce equivalent or better measures of image quality than the compared methods, depending upon the accuracy of the system model used. The novel Bayesian maximum likelihood expectation maximisation technique was shown to be preferable over many existing maximum a posteriori methods due to its simplicity of implementation. A single parameter is required to define the Bayesian prior, which suppresses noise in the solution and may reduce the processing time substantially. Finally, maximum entropy deconvolution was applied as a pre-processing step in single photon emission computed tomography reconstruction of low count data. Higher contrast results were

  6. The concept of entropy. Relation between action and entropy

    Directory of Open Access Journals (Sweden)

    J.-P.Badiali

    2005-01-01

    Full Text Available The Boltzmann expression for entropy represents the traditional link between thermodynamics and statistical mechanics. New theoretical developments like the Unruh effect or the black hole theory suggest a new definition of entropy. In this paper we consider the thermodynamics of black holes as seriously founded and we try to see what we can learn from it in the case of ordinary systems for which a pre-relativistic description is sufficient. We introduce a space-time model and a new definition of entropy considering the thermal equilibrium from a dynamic point of view. Then we show that for black hole and ordinary systems we have the same relation relating a change of entropy to a change of action.

  7. PolyMEMS Actuator: A Polymer-Based Microelectromechanical (MEMS) Actuator with Macroscopic Action

    Science.gov (United States)

    2002-09-01

    DIRECTOR: MICHAEL L. TALBERT, Maj., USAF Technical Advisor , Information Technology Division Information Directorate...technologies meet even two of the four requirements, whereas PolyMEMS meets all four. Robo -Lobster Courtesy of Dr. Joseph Ayers, Northeastern

  8. MEMS: A new approach to micro-optics

    Energy Technology Data Exchange (ETDEWEB)

    Sniegowski, J.J.

    1997-12-31

    MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlights polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.

  9. Nonequilibrium entropies

    International Nuclear Information System (INIS)

    Maes, Christian

    2012-01-01

    In contrast to the quite unique entropy concept useful for systems in (local) thermodynamic equilibrium, there is a variety of quite distinct nonequilibrium entropies, reflecting different physical points. We disentangle these entropies as they relate to heat, fluctuations, response, time asymmetry, variational principles, monotonicity, volume contraction or statistical forces. However, not all of those extensions yield state quantities as understood thermodynamically. At the end we sketch how aspects of dynamical activity can take over for obtaining an extended Clausius relation.

  10. A method for the fast estimation of a battery entropy-variation high-resolution curve - Application on a commercial LiFePO4/graphite cell

    Science.gov (United States)

    Damay, Nicolas; Forgez, Christophe; Bichat, Marie-Pierre; Friedrich, Guy

    2016-11-01

    The entropy-variation of a battery is responsible for heat generation or consumption during operation and its prior measurement is mandatory for developing a thermal model. It is generally done through the potentiometric method which is considered as a reference. However, it requires several days or weeks to get a look-up table with a 5 or 10% SoC (State of Charge) resolution. In this study, a calorimetric method based on the inversion of a thermal model is proposed for the fast estimation of a nearly continuous curve of entropy-variation. This is achieved by separating the heats produced while charging and discharging the battery. The entropy-variation is then deduced from the extracted entropic heat. The proposed method is validated by comparing the results obtained with several current rates to measurements made with the potentiometric method.

  11. 5 V Compatible Two-Axis PZT Driven MEMS Scanning Mirror with Mechanical Leverage Structure for Miniature LiDAR Application.

    Science.gov (United States)

    Ye, Liangchen; Zhang, Gaofei; You, Zheng

    2017-03-05

    The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V. In this paper, we present an ultra-low voltage driven two-axis MEMS scanning mirror which is 5 V compatible. In order to realize low voltage and low power, a two-axis MEMS scanning mirror with mechanical leverage driven by PZT (Lead zirconate titanate) ceramic is designed, modeled, fabricated and characterized. To further decrease the power of the MEMS scanning mirror, a new method of impedance matching for PZT ceramic driven by a two-frequency mixed signal is established. As experimental results show, this MEMS scanning mirror reaches a two-axis scanning angle of 41.9° × 40.3° at a total driving voltage of 4.2 Vpp and total power of 16 mW. The effective diameter of reflection of the mirror is 2 mm and the operating frequencies of two-axis scanning are 947.51 Hz and 1464.66 Hz, respectively.

  12. Entropy and convexity for nonlinear partial differential equations.

    Science.gov (United States)

    Ball, John M; Chen, Gui-Qiang G

    2013-12-28

    Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal processes in a thermodynamic system, while the original notion of convexity is for sets and functions in mathematics. Since then, entropy and convexity have become two of the most important concepts in mathematics. In particular, nonlinear methods via entropy and convexity have been playing an increasingly important role in the analysis of nonlinear partial differential equations in recent decades. This opening article of the Theme Issue is intended to provide an introduction to entropy, convexity and related nonlinear methods for the analysis of nonlinear partial differential equations. We also provide a brief discussion about the content and contributions of the papers that make up this Theme Issue.

  13. Distance-Based Configurational Entropy of Proteins from Molecular Dynamics Simulations.

    Science.gov (United States)

    Fogolari, Federico; Corazza, Alessandra; Fortuna, Sara; Soler, Miguel Angel; VanSchouwen, Bryan; Brancolini, Giorgia; Corni, Stefano; Melacini, Giuseppe; Esposito, Gennaro

    2015-01-01

    Estimation of configurational entropy from molecular dynamics trajectories is a difficult task which is often performed using quasi-harmonic or histogram analysis. An entirely different approach, proposed recently, estimates local density distribution around each conformational sample by measuring the distance from its nearest neighbors. In this work we show this theoretically well grounded the method can be easily applied to estimate the entropy from conformational sampling. We consider a set of systems that are representative of important biomolecular processes. In particular: reference entropies for amino acids in unfolded proteins are obtained from a database of residues not participating in secondary structure elements;the conformational entropy of folding of β2-microglobulin is computed from molecular dynamics simulations using reference entropies for the unfolded state;backbone conformational entropy is computed from molecular dynamics simulations of four different states of the EPAC protein and compared with order parameters (often used as a measure of entropy);the conformational and rototranslational entropy of binding is computed from simulations of 20 tripeptides bound to the peptide binding protein OppA and of β2-microglobulin bound to a citrate coated gold surface. This work shows the potential of the method in the most representative biological processes involving proteins, and provides a valuable alternative, principally in the shown cases, where other approaches are problematic.

  14. Combined Forecasting Method of Landslide Deformation Based on MEEMD, Approximate Entropy, and WLS-SVM

    Directory of Open Access Journals (Sweden)

    Shaofeng Xie

    2017-01-01

    Full Text Available Given the chaotic characteristics of the time series of landslides, a new method based on modified ensemble empirical mode decomposition (MEEMD, approximate entropy and the weighted least square support vector machine (WLS-SVM was proposed. The method mainly started from the chaotic sequence of time-frequency analysis and improved the model performance as follows: first a deformation time series was decomposed into a series of subsequences with significantly different complexity using MEEMD. Then the approximate entropy method was used to generate a new subsequence for the combination of subsequences with similar complexity, which could effectively concentrate the component feature information and reduce the computational scale. Finally the WLS-SVM prediction model was established for each new subsequence. At the same time, phase space reconstruction theory and the grid search method were used to select the input dimension and the optimal parameters of the model, and then the superposition of each predicted value was the final forecasting result. Taking the landslide deformation data of Danba as an example, the experiments were carried out and compared with wavelet neural network, support vector machine, least square support vector machine and various combination schemes. The experimental results show that the algorithm has high prediction accuracy. It can ensure a better prediction effect even in landslide deformation periods of rapid fluctuation, and it can also better control the residual value and effectively reduce the error interval.

  15. High-Order Entropy Stable Finite Difference Schemes for Nonlinear Conservation Laws: Finite Domains

    Science.gov (United States)

    Fisher, Travis C.; Carpenter, Mark H.

    2013-01-01

    Developing stable and robust high-order finite difference schemes requires mathematical formalism and appropriate methods of analysis. In this work, nonlinear entropy stability is used to derive provably stable high-order finite difference methods with formal boundary closures for conservation laws. Particular emphasis is placed on the entropy stability of the compressible Navier-Stokes equations. A newly derived entropy stable weighted essentially non-oscillatory finite difference method is used to simulate problems with shocks and a conservative, entropy stable, narrow-stencil finite difference approach is used to approximate viscous terms.

  16. Nano-tribology and materials in MEMS

    CERN Document Server

    Satyanarayana, N; Lim, Seh

    2013-01-01

    This book brings together recent developments in the areas of MEMS tribology, novel lubricants and coatings for nanotechnological applications, biomimetics in tribology and fundamentals of micro/nano-tribology. Tribology plays important roles in the functioning and durability of machines at small length scales because of the problems associated with strong surface adhesion, friction, wear etc. Recently, a number of studies have been conducted to understand tribological phenomena at nano/micro scales and many new tribological solutions for MEMS have been proposed.

  17. Maximum entropy decomposition of quadrupole mass spectra

    International Nuclear Information System (INIS)

    Toussaint, U. von; Dose, V.; Golan, A.

    2004-01-01

    We present an information-theoretic method called generalized maximum entropy (GME) for decomposing mass spectra of gas mixtures from noisy measurements. In this GME approach to the noisy, underdetermined inverse problem, the joint entropies of concentration, cracking, and noise probabilities are maximized subject to the measured data. This provides a robust estimation for the unknown cracking patterns and the concentrations of the contributing molecules. The method is applied to mass spectroscopic data of hydrocarbons, and the estimates are compared with those received from a Bayesian approach. We show that the GME method is efficient and is computationally fast

  18. Foreign exchange rate entropy evolution during financial crises

    Science.gov (United States)

    Stosic, Darko; Stosic, Dusan; Ludermir, Teresa; de Oliveira, Wilson; Stosic, Tatijana

    2016-05-01

    This paper examines the effects of financial crises on foreign exchange (FX) markets, where entropy evolution is measured for different exchange rates, using the time-dependent block entropy method. Empirical results suggest that financial crises are associated with significant increase of exchange rate entropy, reflecting instability in FX market dynamics. In accordance with phenomenological expectations, it is found that FX markets with large liquidity and large trading volume are more inert - they recover quicker from a crisis than markets with small liquidity and small trading volume. Moreover, our numerical analysis shows that periods of economic uncertainty are preceded by periods of low entropy values, which may serve as a tool for anticipating the onset of financial crises.

  19. On determining absolute entropy without quantum theory or the third law of thermodynamics

    Science.gov (United States)

    Steane, Andrew M.

    2016-04-01

    We employ classical thermodynamics to gain information about absolute entropy, without recourse to statistical methods, quantum mechanics or the third law of thermodynamics. The Gibbs-Duhem equation yields various simple methods to determine the absolute entropy of a fluid. We also study the entropy of an ideal gas and the ionization of a plasma in thermal equilibrium. A single measurement of the degree of ionization can be used to determine an unknown constant in the entropy equation, and thus determine the absolute entropy of a gas. It follows from all these examples that the value of entropy at absolute zero temperature does not need to be assigned by postulate, but can be deduced empirically.

  20. Review of Automated Design and Optimization of MEMS

    DEFF Research Database (Denmark)

    Achiche, Sofiane; Fan, Zhun; Bolognini, Francesca

    2007-01-01

    carried out. This paper presents a review of these techniques. The design task of MEMS is usually divided into four main stages: System Level, Device Level, Physical Level and the Process Level. The state of the art o automated MEMS design in each of these levels is investigated....

  1. Investigation on thermo-acoustic instability dynamic characteristics of hydrocarbon fuel flowing in scramjet cooling channel based on wavelet entropy method

    Science.gov (United States)

    Zan, Hao; Li, Haowei; Jiang, Yuguang; Wu, Meng; Zhou, Weixing; Bao, Wen

    2018-06-01

    As part of our efforts to find ways and means to further improve the regenerative cooling technology in scramjet, the experiments of thermo-acoustic instability dynamic characteristics of hydrocarbon fuel flowing have been conducted in horizontal circular tubes at different conditions. The experimental results indicate that there is a developing process from thermo-acoustic stability to instability. In order to have a deep understanding on the developing process of thermo-acoustic instability, the method of Multi-scale Shannon Wavelet Entropy (MSWE) based on Wavelet Transform Correlation Filter (WTCF) and Multi-Scale Shannon Entropy (MSE) is adopted in this paper. The results demonstrate that the developing process of thermo-acoustic instability from noise and weak signals is well detected by MSWE method and the differences among the stability, the developing process and the instability can be identified. These properties render the method particularly powerful for warning thermo-acoustic instability of hydrocarbon fuel flowing in scramjet cooling channels. The mass flow rate and the inlet pressure will make an influence on the developing process of the thermo-acoustic instability. The investigation on thermo-acoustic instability dynamic characteristics at supercritical pressure based on wavelet entropy method offers guidance on the control of scramjet fuel supply, which can secure stable fuel flowing in regenerative cooling system.

  2. Adaptive Global Sliding Mode Control for MEMS Gyroscope Using RBF Neural Network

    Directory of Open Access Journals (Sweden)

    Yundi Chu

    2015-01-01

    Full Text Available An adaptive global sliding mode control (AGSMC using RBF neural network (RBFNN is proposed for the system identification and tracking control of micro-electro-mechanical system (MEMS gyroscope. Firstly, a new kind of adaptive identification method based on the global sliding mode controller is designed to update and estimate angular velocity and other system parameters of MEMS gyroscope online. Moreover, the output of adaptive neural network control is used to adjust the switch gain of sliding mode control dynamically to approach the upper bound of unknown disturbances. In this way, the switch item of sliding mode control can be converted to the output of continuous neural network which can weaken the chattering in the sliding mode control in contrast to the conventional fixed gain sliding mode control. Simulation results show that the designed control system can get satisfactory tracking performance and effective estimation of unknown parameters of MEMS gyroscope.

  3. The holographic entropy cone

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Ning [Institute for Quantum Information and Matter, California Institute of Technology,Pasadena, CA 91125 (United States); Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Nezami, Sepehr [Stanford Institute for Theoretical Physics, Stanford University,Stanford, CA 94305 (United States); Ooguri, Hirosi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo,Kashiwa 277-8583 (Japan); Stoica, Bogdan [Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Sully, James [Theory Group, SLAC National Accelerator Laboratory, Stanford University,Menlo Park, CA 94025 (United States); Walter, Michael [Stanford Institute for Theoretical Physics, Stanford University,Stanford, CA 94305 (United States)

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.

  4. The holographic entropy cone

    International Nuclear Information System (INIS)

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-01-01

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.

  5. Dissecting Protein Configurational Entropy into Conformational and Vibrational Contributions.

    Science.gov (United States)

    Chong, Song-Ho; Ham, Sihyun

    2015-10-01

    Quantifying how the rugged nature of the underlying free-energy landscape determines the entropic cost a protein must incur upon folding and ligand binding is a challenging problem. Here, we present a novel computational approach that dissects the protein configurational entropy on the basis of the classification of protein dynamics on the landscape into two separate components: short-term vibrational dynamics related to individual free-energy wells and long-term conformational dynamics associated with transitions between wells. We apply this method to separate the configurational entropy of the protein villin headpiece subdomain into its conformational and vibrational components. We find that the change in configurational entropy upon folding is dominated by the conformational entropy despite the fact that the magnitude of the vibrational entropy is the significantly larger component in each of the folded and unfolded states, which is in accord with the previous empirical estimations. The straightforward applicability of our method to unfolded proteins promises a wide range of applications, including those related to intrinsically disordered proteins.

  6. Fault feature extraction method based on local mean decomposition Shannon entropy and improved kernel principal component analysis model

    Directory of Open Access Journals (Sweden)

    Jinlu Sheng

    2016-07-01

    Full Text Available To effectively extract the typical features of the bearing, a new method that related the local mean decomposition Shannon entropy and improved kernel principal component analysis model was proposed. First, the features are extracted by time–frequency domain method, local mean decomposition, and using the Shannon entropy to process the original separated product functions, so as to get the original features. However, the features been extracted still contain superfluous information; the nonlinear multi-features process technique, kernel principal component analysis, is introduced to fuse the characters. The kernel principal component analysis is improved by the weight factor. The extracted characteristic features were inputted in the Morlet wavelet kernel support vector machine to get the bearing running state classification model, bearing running state was thereby identified. Cases of test and actual were analyzed.

  7. MEMS Micro-Valve for Space Applications

    Science.gov (United States)

    Chakraborty, I.; Tang, W. C.; Bame, D. P.; Tang, T. K.

    1998-01-01

    We report on the development of a Micro-ElectroMechanical Systems (MEMS) valve that is designed to meet the rigorous performance requirements for a variety of space applications, such as micropropulsion, in-situ chemical analysis of other planets, or micro-fluidics experiments in micro-gravity. These systems often require very small yet reliable silicon valves with extremely low leak rates and long shelf lives. Also, they must survive the perils of space travel, which include unstoppable radiation, monumental shock and vibration forces, as well as extreme variations in temperature. Currently, no commercial MEMS valve meets these requirements. We at JPL are developing a piezoelectric MEMS valve that attempts to address the unique problem of space. We begin with proven configurations that may seem familiar. However, we have implemented some major design innovations that should produce a superior valve. The JPL micro-valve is expected to have an extremely low leak rate, limited susceptibility to particulates, vibration or radiation, as well as a wide operational temperature range.

  8. Radioisotope Power Sources for MEMS Devices,

    International Nuclear Information System (INIS)

    Blanchard, J.P.

    2001-01-01

    Microelectromechanical systems (MEMS) comprise a rapidly expanding research field with potential applications varying from sensors in airbags to more recent optical applications. Depending on the application, these devices often require an on-board power source for remote operation, especially in cases requiring operation for an extended period of time. Previously suggested power sources include fossil fuels and solar energy, but nuclear power sources may provide significant advantages for certain applications. Hence, the objective of this study is to establish the viability of using radioisotopes to power realistic MEMS devices. A junction-type battery was constructed using silicon and a 63 Ni liquid source. A source volume containing 64 microCi provided a power of ∼0.07 nW. A more novel application of nuclear sources for MEMS applications involves the creation of a resonator that is driven by charge collection in a cantilever beam. Preliminary results have established the feasibility of this concept, and future work will optimize the design for various applications

  9. Calculation of von Neumann entropy for hydrogen and positronium negative ions

    International Nuclear Information System (INIS)

    Lin, Chien-Hao; Ho, Yew Kam

    2014-01-01

    In the present work, we carry out calculations of von Neumann entropies and linear entropies for the hydrogen negative ion and the positronium negative ion. We concentrate on the spatial (electron–electron orbital) entanglement in these ions by using highly correlated Hylleraas functions to represent their ground states, and to take care of correlation effects. We apply the Schmidt decomposition method on the partial-wave expanded two-electron wave functions, and from which the one-particle reduced density matrix can be obtained, leading to the quantifications of linear entropy and von Neumann entropy in the H − and Ps − ions. - Highlights: • We calculate von Neumann entropies and linear entropies for hydrogen and positronium negative ions. • We employ highly correlated Hylleraas functions to take into account of correlation effects. • Spatial (electron–electron orbital) entanglement is quantified using the Schmidt decomposition method. • The eigenvalues of the one-particle reduced density matrix are calculated

  10. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    Energy Technology Data Exchange (ETDEWEB)

    Stubberud, Peter A., E-mail: stubber@ee.unlv.edu [Department of Electrical and Computer Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154 (United States); Stubberud, Stephen C., E-mail: scstubberud@ieee.org [Oakridge Technology, San Diego, CA 92121 (United States); Stubberud, Allen R., E-mail: stubberud@att.net [Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697 (United States)

    2014-12-10

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design

  11. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    International Nuclear Information System (INIS)

    Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

    2014-01-01

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design

  12. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    Science.gov (United States)

    Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

    2014-12-01

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT

  13. Mathematical analysis of partial differential equations modeling electrostatic MEMS

    CERN Document Server

    Esposito, Pierpaolo; Guo, Yujin

    2010-01-01

    Micro- and nanoelectromechanical systems (MEMS and NEMS), which combine electronics with miniature-size mechanical devices, are essential components of modern technology. It is the mathematical model describing "electrostatically actuated" MEMS that is addressed in this monograph. Even the simplified models that the authors deal with still lead to very interesting second- and fourth-order nonlinear elliptic equations (in the stationary case) and to nonlinear parabolic equations (in the dynamic case). While nonlinear eigenvalue problems-where the stationary MEMS models fit-are a well-developed

  14. Additive direct-write microfabrication for MEMS: A review

    Science.gov (United States)

    Teh, Kwok Siong

    2017-12-01

    Direct-write additive manufacturing refers to a rich and growing repertoire of well-established fabrication techniques that builds solid objects directly from computer- generated solid models without elaborate intermediate fabrication steps. At the macroscale, direct-write techniques such as stereolithography, selective laser sintering, fused deposition modeling ink-jet printing, and laminated object manufacturing have significantly reduced concept-to-product lead time, enabled complex geometries, and importantly, has led to the renaissance in fabrication known as the maker movement. The technological premises of all direct-write additive manufacturing are identical—converting computer generated three-dimensional models into layers of two-dimensional planes or slices, which are then reconstructed sequentially into threedimensional solid objects in a layer-by-layer format. The key differences between the various additive manufacturing techniques are the means of creating the finished layers and the ancillary processes that accompany them. While still at its infancy, direct-write additive manufacturing techniques at the microscale have the potential to significantly lower the barrier-of-entry—in terms of cost, time and training—for the prototyping and fabrication of MEMS parts that have larger dimensions, high aspect ratios, and complex shapes. In recent years, significant advancements in materials chemistry, laser technology, heat and fluid modeling, and control systems have enabled additive manufacturing to achieve higher resolutions at the micrometer and nanometer length scales to be a viable technology for MEMS fabrication. Compared to traditional MEMS processes that rely heavily on expensive equipment and time-consuming steps, direct-write additive manufacturing techniques allow for rapid design-to-prototype realization by limiting or circumventing the need for cleanrooms, photolithography and extensive training. With current direct-write additive

  15. Method of Measuring the Mismatch of Parasitic Capacitance in MEMS Accelerometer Based on Regulating Electrostatic Stiffness

    Directory of Open Access Journals (Sweden)

    Xianshan Dong

    2018-03-01

    Full Text Available For the MEMS capacitive accelerometer, parasitic capacitance is a serious problem. Its mismatch will deteriorate the performance of accelerometer. Obtaining the mismatch of the parasitic capacitance precisely is helpful for improving the performance of bias and scale. Currently, the method of measuring the mismatch is limited in the direct measuring using the instrument. This traditional method has low accuracy for it would lead in extra parasitic capacitive and have other problems. This paper presents a novel method based on the mechanism of a closed-loop accelerometer. The strongly linear relationship between the output of electric force and the square of pre-load voltage is obtained through theoretical derivation and validated by experiment. Based on this relationship, the mismatch of parasitic capacitance can be obtained precisely through regulating electrostatic stiffness without other equipment. The results can be applied in the design of decreasing the mismatch and electrical adjusting for eliminating the influence of the mismatch.

  16. Entropy of dynamical social networks

    Science.gov (United States)

    Zhao, Kun; Karsai, Marton; Bianconi, Ginestra

    2012-02-01

    Dynamical social networks are evolving rapidly and are highly adaptive. Characterizing the information encoded in social networks is essential to gain insight into the structure, evolution, adaptability and dynamics. Recently entropy measures have been used to quantify the information in email correspondence, static networks and mobility patterns. Nevertheless, we still lack methods to quantify the information encoded in time-varying dynamical social networks. In this talk we present a model to quantify the entropy of dynamical social networks and use this model to analyze the data of phone-call communication. We show evidence that the entropy of the phone-call interaction network changes according to circadian rhythms. Moreover we show that social networks are extremely adaptive and are modified by the use of technologies such as mobile phone communication. Indeed the statistics of duration of phone-call is described by a Weibull distribution and is significantly different from the distribution of duration of face-to-face interactions in a conference. Finally we investigate how much the entropy of dynamical social networks changes in realistic models of phone-call or face-to face interactions characterizing in this way different type human social behavior.

  17. Nuclear Enhanced X-ray Maximum Entropy Method Used to Analyze Local Distortions in Simple Structures

    DEFF Research Database (Denmark)

    Christensen, Sebastian; Bindzus, Niels; Christensen, Mogens

    We introduce a novel method for reconstructing pseudo nuclear density distributions (NDDs): Nuclear Enhanced X-ray Maximum Entropy Method (NEXMEM). NEXMEM offers an alternative route to experimental NDDs, exploiting the superior quality of synchrotron X-ray data compared to neutron data. The method...... proposed to result from anharmonic phonon scattering or from local fluctuating dipoles on the Pb site.[1,2] No macroscopic symmetry change are associated with these effects, rendering them invisible to conventional crystallographic techniques. For this reason PbX was until recently believed to adopt...

  18. Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods

    Directory of Open Access Journals (Sweden)

    Huiliang Cao

    2016-01-01

    Full Text Available This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC, Quadrature Force Correction (QFC and Coupling Stiffness Correction (CSC methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.

  19. Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods.

    Science.gov (United States)

    Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun

    2016-01-07

    This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses' quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups' output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.

  20. Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods

    Science.gov (United States)

    Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun

    2016-01-01

    This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability. PMID:26751455

  1. Ball driven type MEMS SAD for artillery fuse

    International Nuclear Information System (INIS)

    Seok, Jin Oh; Jeong, Ji-hun; Eom, Junseong; Lee, Seung S; Lee, Chun Jae; Ryu, Sung Moon; Oh, Jong Soo

    2017-01-01

    The SAD (safety and arming device) is an indispensable fuse component that ensures safe and reliable performance during the use of ammunition. Because the application of electronic devices for smart munitions is increasing, miniaturization of the SAD has become one of the key issues for next-generation artillery fuses. Based on MEMS technology, various types of miniaturized SADs have been proposed and fabricated. However, none of them have been reported to have been used in actual munitions due to their lack of high impact endurance and complicated explosive train arrangements. In this research, a new MEMS SAD using a ball driven mechanism, is successfully demonstrated based on a UV LIGA (lithography, electroplating and molding) process. Unlike other MEMS SADs, both high impact endurance and simple structure were achieved by using a ball driven mechanism. The simple structural design also simplified the fabrication process and increased the processing yield. The ball driven type MEMS SAD performed successfully under the desired safe and arming conditions of a spin test and showed fine agreement with the FEM simulation result, conducted prior to its fabrication. A field test was also performed with a grenade launcher to evaluate the SAD performance in the firing environment. All 30 of the grenade samples equipped with the proposed MEMS SAD operated successfully under the high-G setback condition. (paper)

  2. Ball driven type MEMS SAD for artillery fuse

    Science.gov (United States)

    Seok, Jin Oh; Jeong, Ji-hun; Eom, Junseong; Lee, Seung S.; Lee, Chun Jae; Ryu, Sung Moon; Oh, Jong Soo

    2017-01-01

    The SAD (safety and arming device) is an indispensable fuse component that ensures safe and reliable performance during the use of ammunition. Because the application of electronic devices for smart munitions is increasing, miniaturization of the SAD has become one of the key issues for next-generation artillery fuses. Based on MEMS technology, various types of miniaturized SADs have been proposed and fabricated. However, none of them have been reported to have been used in actual munitions due to their lack of high impact endurance and complicated explosive train arrangements. In this research, a new MEMS SAD using a ball driven mechanism, is successfully demonstrated based on a UV LIGA (lithography, electroplating and molding) process. Unlike other MEMS SADs, both high impact endurance and simple structure were achieved by using a ball driven mechanism. The simple structural design also simplified the fabrication process and increased the processing yield. The ball driven type MEMS SAD performed successfully under the desired safe and arming conditions of a spin test and showed fine agreement with the FEM simulation result, conducted prior to its fabrication. A field test was also performed with a grenade launcher to evaluate the SAD performance in the firing environment. All 30 of the grenade samples equipped with the proposed MEMS SAD operated successfully under the high-G setback condition.

  3. Microelectromechanical Systems (MEMS)

    Indian Academy of Sciences (India)

    As a field, Microelectromechanical Systems (MEMS) has matured over the last two decades to have several scientific journals dedicated to it. These journals are instrumental in bringing out the interdisciplinary nature of research that the field demands. In the beginning, most papers were process centric where realization of ...

  4. Standard entropy for borides of non-transition metals, rare-earth metals and actinides

    International Nuclear Information System (INIS)

    Borovikova, M.S.

    1986-01-01

    Using as initial data the most reliable values of standard entropy for 10 compounds, the entropies for 40 compounds of non-transition metals, rare-earth metals and actinides have been evaluated by the method of comparative calculation. Taking into account the features of boride structures, two methods, i.e. additive and proportional, have been selected for the entropy calculations. For the range of borides the entropies were calculated from the linear relation of the latter to the number of boron atoms in the boride. For borides of rare-earth metals allowance has been made for magnetic contributions in conformity with the multiplicity of the corresponding ions. Insignificant differences in the electronic contributions to the entropy for borides and metals have been neglected. For dodecaborides only the additive method has been used. This is specified by the most rigid network that provides the same contribution to compound entropy. (orig.)

  5. Entropy Stable Spectral Collocation Schemes for the Navier-Stokes Equations: Discontinuous Interfaces

    Science.gov (United States)

    Carpenter, Mark H.; Fisher, Travis C.; Nielsen, Eric J.; Frankel, Steven H.

    2013-01-01

    Nonlinear entropy stability and a summation-by-parts framework are used to derive provably stable, polynomial-based spectral collocation methods of arbitrary order. The new methods are closely related to discontinuous Galerkin spectral collocation methods commonly known as DGFEM, but exhibit a more general entropy stability property. Although the new schemes are applicable to a broad class of linear and nonlinear conservation laws, emphasis herein is placed on the entropy stability of the compressible Navier-Stokes equations.

  6. RF MEMS theory, design, and technology

    CERN Document Server

    Rebeiz, Gabriel M

    2003-01-01

    Ultrasmall Radio Frequency and Micro-wave Microelectromechanical systems (RF MEMs), such as switches, varactors, and phase shifters, exhibit nearly zero power consumption or loss. For this reason, they are being developed intensively by corporations worldwide for use in telecommunications equipment. This book acquaints readers with the basics of RF MEMs and describes how to design practical circuits and devices with them. The author, an acknowledged expert in the field, presents a range of real-world applications and shares many valuable tricks of the trade.

  7. The application of entropy weight TOPSIS method to optimal points in monitoring the Xinjiang radiation environment

    International Nuclear Information System (INIS)

    Feng Guangwen; Hu Youhua; Liu Qian

    2009-01-01

    In this paper, the application of the entropy weight TOPSIS method to optimal layout points in monitoring the Xinjiang radiation environment has been indroduced. With the help of SAS software, It has been found that the method is more ideal and feasible. The method can provide a reference for us to monitor radiation environment in the same regions further. As the method could bring great convenience and greatly reduce the inspecting work, it is very simple, flexible and effective for a comprehensive evaluation. (authors)

  8. From MEMS to nanomachine

    International Nuclear Information System (INIS)

    Esashi, Masayoshi; Ono, Takahito

    2005-01-01

    Practically applicable microelectromechanical systems (MEMS) and nanomachines have been developed by applying dry processes. Deep reactive ion etching (RIE) of silicon and its applications to an electrostatically levitated rotational gyroscope, a fibre optic blood pressure sensor and in micro-actuated probes are described. High density electrical feedthrough in glass is made using deep RIE of glass and electroplating of metal. Multi-probe data storage system has been developed using the high density electrical feedthrough in glass. Chemical vapour deposition (CVD) of different materials have been developed for MEMS applications; trench-refill using SiO 2 CVD, microstructures using Silicon carbide CVD for glass mold press and selective CVD of carbon nanotube for electron field emitter. Multi-column electron beam lithography system has been developed using the electron field emitter. (topical review)

  9. Third law of thermodynamics as a key test of generalized entropies.

    Science.gov (United States)

    Bento, E P; Viswanathan, G M; da Luz, M G E; Silva, R

    2015-02-01

    The laws of thermodynamics constrain the formulation of statistical mechanics at the microscopic level. The third law of thermodynamics states that the entropy must vanish at absolute zero temperature for systems with nondegenerate ground states in equilibrium. Conversely, the entropy can vanish only at absolute zero temperature. Here we ask whether or not generalized entropies satisfy this fundamental property. We propose a direct analytical procedure to test if a generalized entropy satisfies the third law, assuming only very general assumptions for the entropy S and energy U of an arbitrary N-level classical system. Mathematically, the method relies on exact calculation of β=dS/dU in terms of the microstate probabilities p(i). To illustrate this approach, we present exact results for the two best known generalizations of statistical mechanics. Specifically, we study the Kaniadakis entropy S(κ), which is additive, and the Tsallis entropy S(q), which is nonadditive. We show that the Kaniadakis entropy correctly satisfies the third law only for -1law for q<1. Finally, we give a concrete example of the power of our proposed method by applying it to a paradigmatic system: the one-dimensional ferromagnetic Ising model with nearest-neighbor interactions.

  10. Statistical properties of quantum entanglement and information entropy

    International Nuclear Information System (INIS)

    Abdel-Aty, M.M.A.

    2007-03-01

    Key words: entropy, entanglement, atom-field interaction, trapped ions, cold atoms, information entropy. Objects of research: Pure state entanglement, entropy squeezing mazer. The aim of the work: Study of the new entanglement features and new measures for both pure-state and mixed state of particle-field interaction. Also, the impact of the information entropy on the quantum information theory. Method of investigation: Methods of theoretical physics and applied mathematics (statistical physics, quantum optics) are used. Results obtained and their novelty are: All the results of the dissertation are new and many new features have been discovered. Particularly: the most general case of the pure state entanglement has been introduced. Although various special aspects of the quantum entropy have been investigated previously, the general features of the dynamics, when a multi-level system and a common environment are considered, have not been treated before and our work therefore, field a gap in the literature. Specifically: 1) A new entanglement measure due to quantum mutual entropy (mixed-state entanglement) we called it DEM, has been introduced, 2) A new treatment of the atomic information entropy in higher level systems has been presented. The problem has been completely solved in the case of three-level system, 3) A new solution of the interaction between the ultra cold atoms and cavity field has been discovered, 4) Some new models of the atom-field interaction have been adopted. Practical value: The subject carries out theoretic character. Application region: Results can be used in quantum computer developments. Also, the presented results can be used for further developments of the quantum information and quantum communications. (author)

  11. Modeling multisite streamflow dependence with maximum entropy copula

    Science.gov (United States)

    Hao, Z.; Singh, V. P.

    2013-10-01

    Synthetic streamflows at different sites in a river basin are needed for planning, operation, and management of water resources projects. Modeling the temporal and spatial dependence structure of monthly streamflow at different sites is generally required. In this study, the maximum entropy copula method is proposed for multisite monthly streamflow simulation, in which the temporal and spatial dependence structure is imposed as constraints to derive the maximum entropy copula. The monthly streamflows at different sites are then generated by sampling from the conditional distribution. A case study for the generation of monthly streamflow at three sites in the Colorado River basin illustrates the application of the proposed method. Simulated streamflow from the maximum entropy copula is in satisfactory agreement with observed streamflow.

  12. On the Conditional Rényi Entropy

    NARCIS (Netherlands)

    S. Fehr (Serge); S. Berens (Stefan)

    2014-01-01

    htmlabstractThe Rényi entropy of general order unifies the well-known Shannon entropy with several other entropy notions, like the min-entropy or the collision entropy. In contrast to the Shannon entropy, there seems to be no commonly accepted definition for the conditional Rényi entropy: several

  13. Music viewed by its entropy content: A novel window for comparative analysis.

    Directory of Open Access Journals (Sweden)

    Gerardo Febres

    Full Text Available Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the '2nd Order Entropy'. Applying these methods to a variety of musical pieces showed how the space of 'symbolic specific diversity-entropy' and that of '2nd order entropy' captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning.

  14. Music viewed by its entropy content: A novel window for comparative analysis.

    Science.gov (United States)

    Febres, Gerardo; Jaffe, Klaus

    2017-01-01

    Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a) a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b) a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c) the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the '2nd Order Entropy'. Applying these methods to a variety of musical pieces showed how the space of 'symbolic specific diversity-entropy' and that of '2nd order entropy' captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning.

  15. Tsallis-like entropies in quantum scattering

    International Nuclear Information System (INIS)

    Ion, D.B.; Ion, M.L.

    1998-01-01

    In this work, the following entropies in quantum scattering are defined: the informational angular entropy, S θ ; Tsallis-like angular entropies, S q (θ); the angular momentum entropy, S L ; the Tsallis-like angular momentum entropies, S q (L); the angle-angular momentum entropy, S θL . These entropies are defined as natural measures of the uncertainties corresponding to the distribution probabilities. If we are interested in obtaining a measure of uncertainty of the simultaneous realization of the probability distributions, than, we have to calculate the entropy corresponding to these distributions. The expression of angle-angular momentum entropy is given. The relation between the Tsallis entropies and the angle-angular momentum entropy is derived

  16. Development of the micro pixel chamber based on MEMS technology

    Science.gov (United States)

    Takemura, T.; Takada, A.; Kishimoto, T.; Komura, S.; Kubo, H.; Matsuoka, Y.; Miuchi, K.; Miyamoto, S.; Mizumoto, T.; Mizumura, Y.; Motomura, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Ohta, K.; Parker, J. D.; Sawano, T.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K.

    2018-02-01

    Micro pixel chambers (μ-PIC) are gaseous two-dimensional imaging detectors originally manufactured using printed circuit board (PCB) technology. They are used in MeV gamma-ray astronomy, medicalimaging, neutron imaging, the search for dark matter, and dose monitoring. The position resolution of the present μ-PIC is approximately 120 μm (RMS), however some applications require a fine position resolution of less than 100 μm. To this end, we have started to develop a μ-PIC based on micro electro mechanical system (MEMS) technology, which provides better manufacturing accuracy than PCB technology. Our simulation predicted the gains of MEMS μ-PICs to be twice those of PCB μ-PICs at the same anode voltage. We manufactured two MEMS μ-PICs and tested them to study their behavior. In these experiments, we successfully operated the fabricatedMEMS μ-PICs and we achieved a maximum gain of approximately 7×103 and collected their energy spectra under irradiation of X-rays from 55Fe. However, the measured gains of the MEMS μ-PICs were less than half of the values predicted in the simulations. We postulated that the gains of the MEMS μ-PICs are diminished by the effect of the silicon used as a semiconducting substrate.

  17. Generalized sample entropy analysis for traffic signals based on similarity measure

    Science.gov (United States)

    Shang, Du; Xu, Mengjia; Shang, Pengjian

    2017-05-01

    Sample entropy is a prevailing method used to quantify the complexity of a time series. In this paper a modified method of generalized sample entropy and surrogate data analysis is proposed as a new measure to assess the complexity of a complex dynamical system such as traffic signals. The method based on similarity distance presents a different way of signals patterns match showing distinct behaviors of complexity. Simulations are conducted over synthetic data and traffic signals for providing the comparative study, which is provided to show the power of the new method. Compared with previous sample entropy and surrogate data analysis, the new method has two main advantages. The first one is that it overcomes the limitation about the relationship between the dimension parameter and the length of series. The second one is that the modified sample entropy functions can be used to quantitatively distinguish time series from different complex systems by the similar measure.

  18. Identification method of gas-liquid two-phase flow regime based on image wavelet packet information entropy and genetic neural network

    International Nuclear Information System (INIS)

    Zhou Yunlong; Chen Fei; Sun Bin

    2008-01-01

    Based on the characteristic that wavelet packet transform image can be decomposed by different scales, a flow regime identification method based on image wavelet packet information entropy feature and genetic neural network was proposed. Gas-liquid two-phase flow images were captured by digital high speed video systems in horizontal pipe. The information entropy feature from transformation coefficients were extracted using image processing techniques and multi-resolution analysis. The genetic neural network was trained using those eigenvectors, which was reduced by the principal component analysis, as flow regime samples, and the flow regime intelligent identification was realized. The test result showed that image wavelet packet information entropy feature could excellently reflect the difference between seven typical flow regimes, and the genetic neural network with genetic algorithm and BP algorithm merits were with the characteristics of fast convergence for simulation and avoidance of local minimum. The recognition possibility of the network could reach up to about 100%, and a new and effective method was presented for on-line flow regime. (authors)

  19. Design and Analysis of MEMS Linear Phased Array

    Directory of Open Access Journals (Sweden)

    Guoxiang Fan

    2016-01-01

    Full Text Available A structure of micro-electro-mechanical system (MEMS linear phased array based on “multi-cell” element is designed to increase radiation sound pressure of transducer working in bending vibration mode at high frequency. In order to more accurately predict the resonant frequency of an element, the theoretical analysis of the dynamic equation of a fixed rectangular composite plate and finite element method simulation are adopted. The effects of the parameters both in the lateral and elevation direction on the three-dimensional beam directivity characteristics are comprehensively analyzed. The key parameters in the analysis include the “cell” number of element, “cell” size, “inter-cell” spacing and the number of elements, element width. The simulation results show that optimizing the linear array parameters both in the lateral and elevation direction can greatly improve the three-dimensional beam focusing for MEMS linear phased array, which is obviously different from the traditional linear array.

  20. Microelectromechanical Systems (MEMS)

    Indian Academy of Sciences (India)

    to have several scientific journals dedicated to it. These journals are instrumental in bringing out the interdisciplinary nature of research that the field demands. In the beginning, most papers were process centric where realization of a MEMS device or structure using conven- tional CMOS processes or their variants was the ...

  1. The Nernst theorem and statistical entropy in a (1+1)-dimensional charged black hole

    International Nuclear Information System (INIS)

    Ren, Z.; Junfang, Z.; Lichun, Z.

    2001-01-01

    It was derived that the bosonic and fermionic entropies in (1+1)-dimensional charged black hole directly by using the quantum statistical method. The result is the same as the integral expression obtained by solving the wave equation approximately. Then it is obtained the statistical entropy of the black hole by integration via the improved brick-wall method, membrane model. The derived entropy satisfies the thermodynamic relation. When the radiation temperature of the black hole tends to zero, so does the entropy. It obeys Nernst theorem. So it can be taken as Planck absolute entropy

  2. Entropy analysis on non-equilibrium two-phase flow models

    International Nuclear Information System (INIS)

    Karwat, H.; Ruan, Y.Q.

    1995-01-01

    A method of entropy analysis according to the second law of thermodynamics is proposed for the assessment of a class of practical non-equilibrium two-phase flow models. Entropy conditions are derived directly from a local instantaneous formulation for an arbitrary control volume of a structural two-phase fluid, which are finally expressed in terms of the averaged thermodynamic independent variables and their time derivatives as well as the boundary conditions for the volume. On the basis of a widely used thermal-hydraulic system code it is demonstrated with practical examples that entropy production rates in control volumes can be numerically quantified by using the data from the output data files. Entropy analysis using the proposed method is useful in identifying some potential problems in two-phase flow models and predictions as well as in studying the effects of some free parameters in closure relationships

  3. Entropy analysis on non-equilibrium two-phase flow models

    Energy Technology Data Exchange (ETDEWEB)

    Karwat, H.; Ruan, Y.Q. [Technische Universitaet Muenchen, Garching (Germany)

    1995-09-01

    A method of entropy analysis according to the second law of thermodynamics is proposed for the assessment of a class of practical non-equilibrium two-phase flow models. Entropy conditions are derived directly from a local instantaneous formulation for an arbitrary control volume of a structural two-phase fluid, which are finally expressed in terms of the averaged thermodynamic independent variables and their time derivatives as well as the boundary conditions for the volume. On the basis of a widely used thermal-hydraulic system code it is demonstrated with practical examples that entropy production rates in control volumes can be numerically quantified by using the data from the output data files. Entropy analysis using the proposed method is useful in identifying some potential problems in two-phase flow models and predictions as well as in studying the effects of some free parameters in closure relationships.

  4. Integrated Electromechanical Transduction Schemes for Polymer MEMS Sensors

    Directory of Open Access Journals (Sweden)

    Damien Thuau

    2018-04-01

    Full Text Available Polymer Micro ElectroMechanical Systems (MEMS have the potential to constitute a powerful alternative to silicon-based MEMS devices for sensing applications. Although the use of commercial photoresists as structural material in polymer MEMS has been widely reported, the integration of functional polymer materials as electromechanical transducers has not yet received the same amount of interest. In this context, we report on the design and fabrication of different electromechanical schemes based on polymeric materials ensuring different transduction functions. Piezoresistive transduction made of carbon nanotube-based nanocomposites with a gauge factor of 200 was embedded within U-shaped polymeric cantilevers operating either in static or dynamic modes. Flexible resonators with integrated piezoelectric transduction were also realized and used as efficient viscosity sensors. Finally, piezoelectric-based organic field effect transistor (OFET electromechanical transduction exhibiting a record sensitivity of over 600 was integrated into polymer cantilevers and used as highly sensitive strain and humidity sensors. Such advances in integrated electromechanical transduction schemes should favor the development of novel all-polymer MEMS devices for flexible and wearable applications in the future.

  5. A numerical investigation of the entropy generation in and thermodynamic optimization of a combustion chamber

    International Nuclear Information System (INIS)

    Arjmandi, H.R.; Amani, E.

    2015-01-01

    In this study, we are simulating the turbulent combustion of a mixed bluff-body swirl stabilized flame in a gas turbine combustion chamber and investigating the effects of different parameters, including the swirl number, distance between the air and fuel nozzle which is called bluff size, equivalence ratio, inlet fuel flow rate, and the inlet air velocity, on the entropy generation. We perform the process of the design of the combustion chamber by proposing the optimal value of each parameter based on the EGM (entropy generation minimization) method under the two maximum allowable temperature and size constraints. Two common methods of entropy generation calculation, one based on the overall entropy balance on a system and the other based on the local entropy generation rate calculation, are used and compared in this study. Our results show that the deviation between the total entropy generations calculated by the two methods is 6.4% in average which is an acceptable error in turbulent combustion simulations. Also, the two opposing factors, namely chemical reaction and heat transfer, have the main contribution to the total entropy generation. - Highlights: • We perform the design of a combustion chamber using CFD and based on the EGM method. • We use and compare two methods for computing the total entropy generation. • We also study the entropy generation due to different phenomena separately. • Reaction and heat transfer have the dominant contribution to the entropy generation

  6. Antenna Miniaturization with MEMS Tunable Capacitors

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

  7. Sputtered highly oriented PZT thin films for MEMS applications

    Science.gov (United States)

    Kalpat, Sriram S.

    Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate

  8. Comprehensive Evaluation of the Sustainable Development of Power Grid Enterprises Based on the Model of Fuzzy Group Ideal Point Method and Combination Weighting Method with Improved Group Order Relation Method and Entropy Weight Method

    Directory of Open Access Journals (Sweden)

    Shuyu Dai

    2017-10-01

    Full Text Available As an important implementing body of the national energy strategy, grid enterprises bear the important responsibility of optimizing the allocation of energy resources and serving the economic and social development, and their levels of sustainable development have a direct impact on the national economy and social life. In this paper, the model of fuzzy group ideal point method and combination weighting method with improved group order relation method and entropy weight method is proposed to evaluate the sustainable development of power grid enterprises. Firstly, on the basis of consulting a large amount of literature, the important criteria of the comprehensive evaluation of the sustainable development of power grid enterprises are preliminarily selected. The opinions of the industry experts are consulted and fed back for many rounds through the Delphi method and the evaluation criteria system for sustainable development of power grid enterprises is determined, then doing the consistent and non dimensional processing of the evaluation criteria. After that, based on the basic order relation method, the weights of each expert judgment matrix are synthesized to construct the compound matter elements. By using matter element analysis, the subjective weights of the criteria are obtained. And entropy weight method is used to determine the objective weights of the preprocessed criteria. Then, combining the subjective and objective information with the combination weighting method based on the subjective and objective weighted attribute value consistency, a more comprehensive, reasonable and accurate combination weight is calculated. Finally, based on the traditional TOPSIS method, the triangular fuzzy numbers are introduced to better realize the scientific processing of the data information which is difficult to quantify, and the queuing indication value of each object and the ranking result are obtained. A numerical example is taken to prove that the

  9. Entropy of the electroencephalogram as applied in the M-Entropy S ...

    African Journals Online (AJOL)

    Background: It has been suggested that spectral entropy of the electroencephalogram as applied in the M-Entropy S/5TM Module (GE Healthcare) does not detect the effects of nitrous oxide (N2O). The aim of this study was to investigate the effect on entropy by graded increases in N2O concentrations in the presence of a ...

  10. Entropy of Baker's Transformation

    Institute of Scientific and Technical Information of China (English)

    栾长福

    2003-01-01

    Four theorems about four different kinds of entropies for Baker's transformation are presented. The Kolmogorov entropy of Baker's transformation is sensitive to the initial flips by the time. The topological entropy of Baker's transformation is found to be log k. The conditions for the state of Baker's transformation to be forbidden are also derived. The relations among the Shanonn, Kolmogorov, topological and Boltzmann entropies are discussed in details.

  11. The Dynameomics Entropy Dictionary: A Large-Scale Assessment of Conformational Entropy across Protein Fold Space.

    Science.gov (United States)

    Towse, Clare-Louise; Akke, Mikael; Daggett, Valerie

    2017-04-27

    Molecular dynamics (MD) simulations contain considerable information with regard to the motions and fluctuations of a protein, the magnitude of which can be used to estimate conformational entropy. Here we survey conformational entropy across protein fold space using the Dynameomics database, which represents the largest existing data set of protein MD simulations for representatives of essentially all known protein folds. We provide an overview of MD-derived entropies accounting for all possible degrees of dihedral freedom on an unprecedented scale. Although different side chains might be expected to impose varying restrictions on the conformational space that the backbone can sample, we found that the backbone entropy and side chain size are not strictly coupled. An outcome of these analyses is the Dynameomics Entropy Dictionary, the contents of which have been compared with entropies derived by other theoretical approaches and experiment. As might be expected, the conformational entropies scale linearly with the number of residues, demonstrating that conformational entropy is an extensive property of proteins. The calculated conformational entropies of folding agree well with previous estimates. Detailed analysis of specific cases identifies deviations in conformational entropy from the average values that highlight how conformational entropy varies with sequence, secondary structure, and tertiary fold. Notably, α-helices have lower entropy on average than do β-sheets, and both are lower than coil regions.

  12. The maximum entropy production and maximum Shannon information entropy in enzyme kinetics

    Science.gov (United States)

    Dobovišek, Andrej; Markovič, Rene; Brumen, Milan; Fajmut, Aleš

    2018-04-01

    We demonstrate that the maximum entropy production principle (MEPP) serves as a physical selection principle for the description of the most probable non-equilibrium steady states in simple enzymatic reactions. A theoretical approach is developed, which enables maximization of the density of entropy production with respect to the enzyme rate constants for the enzyme reaction in a steady state. Mass and Gibbs free energy conservations are considered as optimization constraints. In such a way computed optimal enzyme rate constants in a steady state yield also the most uniform probability distribution of the enzyme states. This accounts for the maximal Shannon information entropy. By means of the stability analysis it is also demonstrated that maximal density of entropy production in that enzyme reaction requires flexible enzyme structure, which enables rapid transitions between different enzyme states. These results are supported by an example, in which density of entropy production and Shannon information entropy are numerically maximized for the enzyme Glucose Isomerase.

  13. Ultra-compact MEMS FTIR spectrometer

    Science.gov (United States)

    Sabry, Yasser M.; Hassan, Khaled; Anwar, Momen; Alharon, Mohamed H.; Medhat, Mostafa; Adib, George A.; Dumont, Rich; Saadany, Bassam; Khalil, Diaa

    2017-05-01

    Portable and handheld spectrometers are being developed and commercialized in the late few years leveraging the rapidly-progressing technology and triggering new markets in the field of on-site spectroscopic analysis. Although handheld devices were commercialized for the near-infrared spectroscopy (NIRS), their size and cost stand as an obstacle against the deployment of the spectrometer as spectral sensing components needed for the smart phone industry and the IoT applications. In this work we report a chip-sized microelectromechanical system (MEMS)-based FTIR spectrometer. The core optical engine of the solution is built using a passive-alignment integration technique for a selfaligned MEMS chip; self-aligned microoptics and a single detector in a tiny package sized about 1 cm3. The MEMS chip is a monolithic, high-throughput scanning Michelson interferometer fabricated using deep reactive ion etching technology of silicon-on-insulator substrate. The micro-optical part is used for conditioning the input/output light to/from the MEMS and for further light direction to the detector. Thanks to the all-reflective design of the conditioning microoptics, the performance is free of chromatic aberration. Complemented by the excellent transmission properties of the silicon in the infrared region, the integrated solution allows very wide spectral range of operation. The reported sensor's spectral resolution is about 33 cm-1 and working in the range of 1270 nm to 2700 nm; upper limited by the extended InGaAs detector. The presented solution provides a low cost, low power, tiny size, wide wavelength range NIR spectral sensor that can be manufactured with extremely high volumes. All these features promise the compatibility of this technology with the forthcoming demand of smart portable and IoT devices.

  14. Entropy production in a cell and reversal of entropy flow as an anticancer therapy

    Institute of Scientific and Technical Information of China (English)

    Liao-fu LUO

    2009-01-01

    The entropy production rate of cancer cells is always higher than healthy cells in the case where no external field is applied. Different entropy production between two kinds of cells determines the direction of entropy flow among cells. The entropy flow is the carrier of information flow. The entropy flow from cancerous cells to healthy cells takes along the harmful information of cancerous cells, propagating its toxic action to healthy tissues. We demonstrate that a low-frequency and low- intensity electromagnetic field or ultrasound irradiation may increase the entropy production rate of a cell in normal tissue than that in cancer and consequently re- verse the direction of entropy current between two kinds of cells. The modification of the PH value of cells may also cause the reversal of the direction of entropy flow between healthy and cancerous cells. Therefore, the bio- logical tissue under the irradiation of an electromagnetic field or ultrasound or under the appropriate change of cell acidity can avoid the propagation of harmful infor- marion from cancer cells. We suggest that this entropy mechanism possibly provides a basis for a novel approach to anticancer therapy.

  15. Vector entropy imaging theory with application to computerized tomography

    International Nuclear Information System (INIS)

    Wang Yuanmei; Cheng Jianping; Heng, Pheng Ann

    2002-01-01

    Medical imaging theory for x-ray CT and PET is based on image reconstruction from projections. In this paper a novel vector entropy imaging theory under the framework of multiple criteria decision making is presented. We also study the most frequently used image reconstruction methods, namely, least square, maximum entropy, and filtered back-projection methods under the framework of the single performance criterion optimization. Finally, we introduce some of the results obtained by various reconstruction algorithms using computer-generated noisy projection data from the Hoffman phantom and real CT scanner data. Comparison of the reconstructed images indicates that the vector entropy method gives the best in error (difference between the original phantom data and reconstruction), smoothness (suppression of noise), grey value resolution and is free of ghost images. (author)

  16. MINIMUM ENTROPY DECONVOLUTION OF ONE-AND MULTI-DIMENSIONAL NON-GAUSSIAN LINEAR RANDOM PROCESSES

    Institute of Scientific and Technical Information of China (English)

    程乾生

    1990-01-01

    The minimum entropy deconvolution is considered as one of the methods for decomposing non-Gaussian linear processes. The concept of peakedness of a system response sequence is presented and its properties are studied. With the aid of the peakedness, the convergence theory of the minimum entropy deconvolution is established. The problem of the minimum entropy deconvolution of multi-dimensional non-Gaussian linear random processes is first investigated and the corresponding theory is given. In addition, the relation between the minimum entropy deconvolution and parameter method is discussed.

  17. Políticas Públicas de Memória O Programa Pontos de Memória no Contexto Sul-Rio-Grandense

    Directory of Open Access Journals (Sweden)

    Mariana Boujadi Mariano da Silva

    2016-12-01

    Full Text Available O presente estudo busca realizar uma análise do Programa Pontos de Memória, do Instituto Brasileiro de Museus. Analisando o Programa, observa-se a iniciativa de preservar a memória de determinados grupos sociais considerados excluídos da representação de museus ditos tradicionais, através da implementação de espaços de memória ou ações sociomuseológicas, que narrem suas histórias a partir do suporte de patrimônios locais. A análise parte de questionamentos iniciais: quais são as memórias e as identidades que o Programa seleciona para narrar, através de quais ferramentas ocorre a divulgação e sobretudo a apropriação deste patrimônio por parte da comunidade? Para analisar as causas e os efeitos desta política pública, o trabalho observará e discutirá o alcance e a influência que esses espaços exercem nas comunidades, as ações desenvolvidas e a longevidade desses espaços ou ações no contexto sul-rio-grandense.

  18. Design and Simulation of an RF-MEMS Switch and analysis of its Electromagnetic aspect in realtion to stress

    Directory of Open Access Journals (Sweden)

    Amna Riaz

    2018-01-01

    Full Text Available Microelectromechanical Systems (MEMS are devices made up of several electrical and mechanical components. They consist of mechanical functions (sensing, thermal, inertial and electrical functions (switching, decision making on a single chip made by microfabrication methods. These chips exhibit combined properties of the two functions. The size of system has characteristic dimensions less than 1mm but more than 1μm. The configuration of these components determine the final deliverables of the switch. MEMS can be designed to meet user requirements on any level from microbiological application such as biomedical transducers or tissue engineering, to mechanical systems such as microfluidic diagnoses or chemical fuel cells. The low cost, small mass and minimal power consumption of the MEMS makes it possible to readily integrate to any kind of system in any environment. MEMS are faster, better and cheaper. They offer excellent electrical performances. MEMS working at Radio frequencies are RF MEMS. RF-MEMS switches find huge market in the modern telecommunication networks, biological, automobiles, satellites and defense systems because of their lower power consumptions at relatively higher frequencies and better electrical performances. But the reliability is the major hurdle in the fate of RF MEMS switches. Reliability mainly arises due to the presence of residual stresses, charging current, fatigue and creep and contact degradation. The presence of residual stresses in switches the S-Parameters of the switches are affected badly and the residual stress affects the final planarity of the fabricated structure. Design and simulation of an RF-MEMS switch is proposed considering the residual stresses in both on and off state. The operating frequency band is being optimized and the best possible feasible fabrication technique for the proposed switch design is being analyzed. S-Parameters are calculated and a comparison for the switches with stress and

  19. The different paths to entropy

    International Nuclear Information System (INIS)

    Benguigui, L

    2013-01-01

    In order to understand how the complex concept of entropy emerged, we propose a trip into the past, reviewing the works of Clausius, Boltzmann, Gibbs and Planck. In particular, since Gibbs's work is not very well known we present a detailed analysis, recalling the three definitions of entropy that Gibbs gives. The introduction of entropy in quantum mechanics gives in a compact form all the classical definitions of entropy. Perhaps one of the most important aspects of entropy is to see it as a thermodynamic potential like the others proposed by Callen. The calculation of fluctuations in thermodynamic quantities is thus naturally related to entropy. We close with some remarks on entropy and irreversibility. (paper)

  20. A Review on Key Issues and Challenges in Devices Level MEMS Testing

    Directory of Open Access Journals (Sweden)

    Muhammad Shoaib

    2016-01-01

    Full Text Available The present review provides information relevant to issues and challenges in MEMS testing techniques that are implemented to analyze the microelectromechanical systems (MEMS behavior for specific application and operating conditions. MEMS devices are more complex and extremely diverse due to the immersion of multidomains. Their failure modes are distinctive under different circumstances. Therefore, testing of these systems at device level as well as at mass production level, that is, parallel testing, is becoming very challenging as compared to the IC test, because MEMS respond to electrical, physical, chemical, and optical stimuli. Currently, test systems developed for MEMS devices have to be customized due to their nondeterministic behavior and complexity. The accurate measurement of test systems for MEMS is difficult to quantify in the production phase. The complexity of the device to be tested required maturity in the test technique which increases the cost of test development; this practice is directly imposed on the device cost. This factor causes a delay in time-to-market.

  1. ENTROPY - OUR BEST FRIEND

    Directory of Open Access Journals (Sweden)

    Urban Kordes

    2005-10-01

    Full Text Available The paper tries to tackle the question of connection between entropy and the living. Definitions of life as the phenomenon that defies entropy are overviewed and the conclusion is reached that life is in a way dependant on entropy - it couldn't exist without it. Entropy is a sort of medium, a fertile soil, that gives life possibility to blossom. Paper ends with presenting some consequences for the field of artificial intelligence.

  2. Application of maximum entropy to neutron tunneling spectroscopy

    International Nuclear Information System (INIS)

    Mukhopadhyay, R.; Silver, R.N.

    1990-01-01

    We demonstrate the maximum entropy method for the deconvolution of high resolution tunneling data acquired with a quasielastic spectrometer. Given a precise characterization of the instrument resolution function, a maximum entropy analysis of lutidine data obtained with the IRIS spectrometer at ISIS results in an effective factor of three improvement in resolution. 7 refs., 4 figs

  3. Entropy of balance - some recent results

    Directory of Open Access Journals (Sweden)

    Laxåback Gerd

    2010-07-01

    Full Text Available Abstract Background Entropy when applied to biological signals is expected to reflect the state of the biological system. However the physiological interpretation of the entropy is not always straightforward. When should high entropy be interpreted as a healthy sign, and when as marker of deteriorating health? We address this question for the particular case of human standing balance and the Center of Pressure data. Methods We have measured and analyzed balance data of 136 participants (young, n = 45; elderly, n = 91 comprising in all 1085 trials, and calculated the Sample Entropy (SampEn for medio-lateral (M/L and anterior-posterior (A/P Center of Pressure (COP together with the Hurst self-similariy (ss exponent α using Detrended Fluctuation Analysis (DFA. The COP was measured with a force plate in eight 30 seconds trials with eyes closed, eyes open, foam, self-perturbation and nudge conditions. Results 1 There is a significant difference in SampEn for the A/P-direction between the elderly and the younger groups Old > young. 2 For the elderly we have in general A/P > M/L. 3 For the younger group there was no significant A/P-M/L difference with the exception for the nudge trials where we had the reverse situation, A/P Eyes Open. 5 In case of the Hurst ss-exponent we have for the elderly, M/L > A/P. Conclusions These results seem to be require some modifications of the more or less established attention-constraint interpretation of entropy. This holds that higher entropy correlates with a more automatic and a less constrained mode of balance control, and that a higher entropy reflects, in this sense, a more efficient balancing.

  4. Irreversible entropy model for damage diagnosis in resistors

    Energy Technology Data Exchange (ETDEWEB)

    Cuadras, Angel, E-mail: angel.cuadras@upc.edu; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos [Instrumentation, Sensor and Interfaces Group, Electronic Engineering Department, Escola d' Enginyeria de Telecomunicació i Aeronàutica de Castelldefels EETAC, Universitat Politècnica de Catalunya, Barcelona Tech (UPC), Castelldefels-Barcelona (Spain)

    2015-10-28

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

  5. Irreversible entropy model for damage diagnosis in resistors

    International Nuclear Information System (INIS)

    Cuadras, Angel; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos

    2015-01-01

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance

  6. A low-noise MEMS accelerometer for unattended ground sensor applications

    Science.gov (United States)

    Speller, Kevin E.; Yu, Duli

    2004-09-01

    A low-noise micro-machined servo accelerometer has been developed for use in Unattended Ground Sensors (UGS). Compared to conventional coil-and-magnet based velocity transducers, this Micro-Electro-Mechanical System (MEMS) accelerometer offers several key benefits for battlefield monitoring. Many UGS require a compass to determine deployment orientation with respect to magnetic North. This orientation information is critical for determining the bearing of incoming signals. Conventional sensors with sensing technology based on a permanent magnet can cause interference with a compass when used in close proximity. This problem is solved with a MEMS accelerometer which does not require any magnetic materials. Frequency information below 10 Hz is valuable for identification of signal sources. Conventional seismometers used in UGS are typically limited in frequency response from 20 to 200 Hz. The MEMS accelerometer has a flat frequency response from DC to 5 kHz. The wider spectrum of signals received improves detection, classification and monitoring on the battlefield. The DC-coupled output of the MEMS accelerometer also has the added benefit of providing tilt orientation data for the deployed UGS. Other performance parameters of the MEMS accelerometer that are important to UGS such as size, weight, shock survivability, phase response, distortion, and cross-axis rejection will be discussed. Additionally, field test data from human footsteps recorded with the MEMS accelerometer will be presented.

  7. Improving performance of two-phase natural circulation loops by reducing of entropy generation

    International Nuclear Information System (INIS)

    Goudarzi, N.; Talebi, S.

    2015-01-01

    This paper aims to investigate the effects of various parameters on stability behavior and entropy generation through a two-phase natural circulation loop. Two-phase natural circulation systems have low driving head and, consequently, low heat removal capability. To have a higher thermodynamic efficiency, in addition to the stability analysis, minimization of entropy generation by loop should be taken into account in the design of these systems. In the present study, to investigate the stability behavior, the non-linear method (known as the direct solution method or time domain method) which is able to simulate the uniform and non-uniform diameter loops, was applied. To best calculate entropy generation rates, the governing equations of the entropy generation were solved analytically. The effects of various parameters such as operating conditions and geometrical dimensions on the stability behavior and the entropy generation in the two-phase natural circulation loop were then analyzed. - Highlights: • Effects of all important parameters on entropy generation of a loop are studied. • The governing equations of the entropy generation are solved analytically. • Effects of all important parameters on stability of a loop are investigated. • Improvement of two-phase natural circulation loop is investigated.

  8. Editorial: Entropy in Landscape Ecology

    Directory of Open Access Journals (Sweden)

    Samuel A. Cushman

    2018-04-01

    Full Text Available Entropy and the second law of thermodynamics are the central organizing principles of nature, but the ideas and implications of the second law are poorly developed in landscape ecology. The purpose of this Special Issue “Entropy in Landscape Ecology” in Entropy is to bring together current research on applications of thermodynamics in landscape ecology, to consolidate current knowledge and identify key areas for future research. The special issue contains six articles, which cover a broad range of topics including relationships between entropy and evolution, connections between fractal geometry and entropy, new approaches to calculate configurational entropy of landscapes, example analyses of computing entropy of landscapes, and using entropy in the context of optimal landscape planning. Collectively these papers provide a broad range of contributions to the nascent field of ecological thermodynamics. Formalizing the connections between entropy and ecology are in a very early stage, and that this special issue contains papers that address several centrally important ideas, and provides seminal work that will be a foundation for the future development of ecological and evolutionary thermodynamics.

  9. A projection-adapted cross entropy (PACE) method for transmission network planning

    Energy Technology Data Exchange (ETDEWEB)

    Eshragh, Ali; Filar, Jerzy [University of South Australia, School of Mathematics and Statistics, Mawson Lakes, SA (Australia); Nazar, Asef [University of South Australia, Institute for Sustainable Systems Technologies, School of Mathematics and Statistics, Mawson Lakes, SA (Australia)

    2011-06-15

    In this paper, we propose an adaptation of the cross entropy (CE) method called projection-adapted CE (PACE) to solve a transmission expansion problem that arises in management of national and provincial electricity grids. The aim of the problem is to find an expansion policy that is both economical and operational from the technical perspective. Often, the transmission network expansion problem is mathematically formulated as a mixed integer nonlinear program that is very challenging algorithmically. The challenge originates from the fact that a global optimum should be found despite the presence, of possibly a huge number, of local optima. The PACE method shows promise in solving global optimization problems regardless of continuity or other assumptions. In our approach, we sample the integer variables using the CE mechanism, and solve LPs to obtain matching continuous variables. Numerical results, on selected test systems, demonstrate the potential of this approach. (orig.)

  10. Calculating topological entropy for transient chaos with an application to communicating with chaos

    International Nuclear Information System (INIS)

    Jacobs, J.; Ott, E.; Hunt, B.R.

    1998-01-01

    Recent work on communicating with chaos provides a practical motivation for being able to determine numerically the topological entropy for chaotic invariant sets. In this paper we discuss numerical methods for evaluating topological entropy. To assess the accuracy and convergence of the methods, we test them in situations where the topological entropy is known independently. We also discuss the entropy of invariant chaotic saddles formed by those points in a given attractor that never visit some forbidden 'gap' region. Such gaps have been proposed as a means of providing noise immunity in schemes for communication with chaos, and we discuss the dependence of the topological entropy on the size of the gap. copyright 1998 The American Physical Society

  11. Improvement of the detector resolution in X-ray spectrometry by using the maximum entropy method

    International Nuclear Information System (INIS)

    Fernández, Jorge E.; Scot, Viviana; Giulio, Eugenio Di; Sabbatucci, Lorenzo

    2015-01-01

    In every X-ray spectroscopy measurement the influence of the detection system causes loss of information. Different mechanisms contribute to form the so-called detector response function (DRF): the detector efficiency, the escape of photons as a consequence of photoelectric or scattering interactions, the spectrum smearing due to the energy resolution, and, in solid states detectors (SSD), the charge collection artifacts. To recover the original spectrum, it is necessary to remove the detector influence by solving the so-called inverse problem. The maximum entropy unfolding technique solves this problem by imposing a set of constraints, taking advantage of the known a priori information and preserving the positive-defined character of the X-ray spectrum. This method has been included in the tool UMESTRAT (Unfolding Maximum Entropy STRATegy), which adopts a semi-automatic strategy to solve the unfolding problem based on a suitable combination of the codes MAXED and GRAVEL, developed at PTB. In the past UMESTRAT proved the capability to resolve characteristic peaks which were revealed as overlapped by a Si SSD, giving good qualitative results. In order to obtain quantitative results, UMESTRAT has been modified to include the additional constraint of the total number of photons of the spectrum, which can be easily determined by inverting the diagonal efficiency matrix. The features of the improved code are illustrated with some examples of unfolding from three commonly used SSD like Si, Ge, and CdTe. The quantitative unfolding can be considered as a software improvement of the detector resolution. - Highlights: • Radiation detection introduces distortions in X- and Gamma-ray spectrum measurements. • UMESTRAT is a graphical tool to unfold X- and Gamma-ray spectra. • UMESTRAT uses the maximum entropy method. • UMESTRAT’s new version produces unfolded spectra with quantitative meaning. • UMESTRAT is a software tool to improve the detector resolution.

  12. On quantum Rényi entropies

    DEFF Research Database (Denmark)

    Müller-Lennert, Martin; Dupont-Dupuis, Fréderic; Szehr, Oleg

    2013-01-01

    The Rényi entropies constitute a family of information measures that generalizes the well-known Shannon entropy, inheriting many of its properties. They appear in the form of unconditional and conditional entropies, relative entropies, or mutual information, and have found many applications in in...

  13. Modeling and non-linear responses of MEMS capacitive accelerometer

    Directory of Open Access Journals (Sweden)

    Sri Harsha C.

    2014-01-01

    Full Text Available A theoretical investigation of an electrically actuated beam has been illustrated when the electrostatic-ally actuated micro-cantilever beam is separated from the electrode by a moderately large gap for two distinct types of geometric configurations of MEMS accelerometer. Higher order nonlinear terms have been taken into account for studying the pull in voltage analysis. A nonlinear model of gas film squeezing damping, another source of nonlinearity in MEMS devices is included in obtaining the dynamic responses. Moreover, in the present work, the possible source of nonlinearities while formulating the mathematical model of a MEMS accelerometer and their influences on the dynamic responses have been investigated. The theoretical results obtained by using MATLAB has been verified with the results obtained in FE software and has been found in good agreement. Criterion towards stable micro size accelerometer for each configuration has been investigated. This investigation clearly provides an understanding of nonlinear static and dynamics characteristics of electrostatically micro cantilever based device in MEMS.

  14. Thin Film Transistor Control Circuitry for MEMS Acoustic Transducers

    Science.gov (United States)

    Daugherty, Robin

    This work seeks to develop a practical solution for short range ultrasonic communications and produce an integrated array of acoustic transmitters on a flexible substrate. This is done using flexible thin film transistor (TFT) and micro electromechanical systems (MEMS). The goal is to develop a flexible system capable of communicating in the ultrasonic frequency range at a distance of 10-100 meters. This requires a great deal of innovation on the part of the FDC team developing the TFT driving circuitry and the MEMS team adapting the technology for fabrication on a flexible substrate. The technologies required for this research are independently developed. The TFT development is driven primarily by research into flexible displays. The MEMS development is driving by research in biosensors and micro actuators. This project involves the integration of TFT flexible circuit capabilities with MEMS micro actuators in the novel area of flexible acoustic transmitter arrays. This thesis focuses on the design, testing and analysis of the circuit components required for this project.

  15. Entanglement entropy of ABJM theory and entropy of topological black hole

    Science.gov (United States)

    Nian, Jun; Zhang, Xinyu

    2017-07-01

    In this paper we discuss the supersymmetric localization of the 4D N = 2 offshell gauged supergravity on the background of the AdS4 neutral topological black hole, which is the gravity dual of the ABJM theory defined on the boundary {S}^1× H^2 . We compute the large- N expansion of the supergravity partition function. The result gives the black hole entropy with the logarithmic correction, which matches the previous result of the entanglement entropy of the ABJM theory up to some stringy effects. Our result is consistent with the previous on-shell one-loop computation of the logarithmic correction to black hole entropy. It provides an explicit example of the identification of the entanglement entropy of the boundary conformal field theory with the bulk black hole entropy beyond the leading order given by the classical Bekenstein-Hawking formula, which consequently tests the AdS/CFT correspondence at the subleading order.

  16. Sample Entropy-Based Approach to Evaluate the Stability of Double-Wire Pulsed MIG Welding

    Directory of Open Access Journals (Sweden)

    Ping Yao

    2014-01-01

    Full Text Available According to the sample entropy, this paper deals with a quantitative method to evaluate the current stability in double-wire pulsed MIG welding. Firstly, the sample entropy of current signals with different stability but the same parameters is calculated. The results show that the more stable the current, the smaller the value and the standard deviation of sample entropy. Secondly, four parameters, which are pulse width, peak current, base current, and frequency, are selected for four-level three-factor orthogonal experiment. The calculation and analysis of desired signals indicate that sample entropy values are affected by welding current parameters. Then, a quantitative method based on sample entropy is proposed. The experiment results show that the method can preferably quantify the welding current stability.

  17. Bayesian and maximum entropy methods for fusion diagnostic measurements with compact neutron spectrometers

    International Nuclear Information System (INIS)

    Reginatto, Marcel; Zimbal, Andreas

    2008-01-01

    In applications of neutron spectrometry to fusion diagnostics, it is advantageous to use methods of data analysis which can extract information from the spectrum that is directly related to the parameters of interest that describe the plasma. We present here methods of data analysis which were developed with this goal in mind, and which were applied to spectrometric measurements made with an organic liquid scintillation detector (type NE213). In our approach, we combine Bayesian parameter estimation methods and unfolding methods based on the maximum entropy principle. This two-step method allows us to optimize the analysis of the data depending on the type of information that we want to extract from the measurements. To illustrate these methods, we analyze neutron measurements made at the PTB accelerator under controlled conditions, using accelerator-produced neutron beams. Although the methods have been chosen with a specific application in mind, they are general enough to be useful for many other types of measurements

  18. Thermal Desalination using MEMS and Salinity-Gradient Solar Pond Technology

    Science.gov (United States)

    Lu, H.; Walton, J. C.; Hein, H.

    2002-08-01

    MEMS (multi-effect, multi-stage) flash desalination (distillation) driven by thermal energy derived from a salinity-gradient solar pond is investigated in this study for the purpose of improving the thermodynamic efficiency and economics of this technology. Three major tasks are performed: (1) a MEMS unit is tested under various operating conditions at the El Paso Solar Pond site; (2) the operation and maintenance procedures of the salinity-gradient solar pond coupled with the MEMS operation is studied; and (3) previous test data on a 24-stage, falling-film flash distillation unit (known as the Spinflash) is analyzed and compared with the performance of the MEMS unit. The data and information obtained from this investigation is applicable to a variety of thermal desalination processes using other solar options and/or waste heat.

  19. MEMS Actuators for Improved Performance and Durability

    Science.gov (United States)

    Yearsley, James M.

    Micro-ElectroMechanical Systems (MEMS) devices take advantage of force-scaling at length scales smaller than a millimeter to sense and interact with directly with phenomena and targets at the microscale. MEMS sensors found in everyday devices like cell-phones and cars include accelerometers, gyros, pressure sensors, and magnetic sensors. MEMS actuators generally serve more application specific roles including micro- and nano-tweezers used for single cell manipulation, optical switching and alignment components, and micro combustion engines for high energy density power generation. MEMS rotary motors are actuators that translate an electric drive signal into rotational motion and can serve as rate calibration inputs for gyros, stages for optical components, mixing devices for micro-fluidics, etc. Existing rotary micromotors suffer from friction and wear issues that affect lifetime and performance. Attempts to alleviate friction effects include surface treatment, magnetic and electrostatic levitation, pressurized gas bearings, and micro-ball bearings. The present work demonstrates a droplet based liquid bearing supporting a rotary micromotor that improves the operating characteristics of MEMS rotary motors. The liquid bearing provides wear-free, low-friction, passive alignment between the rotor and stator. Droplets are positioned relative to the rotor and stator through patterned superhydrophobic and hydrophilic surface coatings. The liquid bearing consists of a central droplet that acts as the motor shaft, providing axial alignment between rotor and stator, and satellite droplets, analogous to ball-bearings, that provide tip and tilt stable operation. The liquid bearing friction performance is characterized through measurement of the rotational drag coefficient and minimum starting torque due to stiction and geometric effects. Bearing operational performance is further characterized by modeling and measuring stiffness, environmental survivability, and high

  20. Entropy-Stabilized Oxides

    Science.gov (United States)

    2015-09-29

    antiferroelectrics. Phys. Rev. Lett. 110, 017603 (2013). 22. Cantor , B., Chang, I., Knight, P. & Vincent, A. Microstructural development in equiatomic...Science 345, 1153–1158 (2014). 24. Gali, A. & George , E. Tensile properties of high- and medium-entropy alloys. Intermetallics 39, 74–78 (2013). 25...148–153 (2014). 26. Otto, F., Yang, Y., Bei, H. & George , E. Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy