4,723 research outputs found

    A study on the turbulent transport of an advective nature in the fluid plasma

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    Advective nature of the electrostatic turbulent flux of plasma energy is studied numerically in a nearly adiabatic state. Such a state is represented by the Hasegawa-Mima equation that is driven by a noise that may model the destabilization due to the phase mismatch of the plasma density and the electric potential. The noise is assumed to be Gaussian and not to be invariant under reflection along a direction s^\hat s. It is found that the flux density induced by such noise is anisotropic: While it is random along s^\hat s, it is not along the perpendicular direction s^{\hat s}_\perp and the flux is not diffusive. The renormalized response may be approximated as advective with the velocity being proportional to (kρs)2(k\rho_s)^2 in the Fourier space k\vec k

    Robust and reliable HH_\infty output feedback control for linear systems with parameter uncertainty and actuator failure

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    summary:The robust and reliable HH_{\infty } output feedback controller design problem is investigated for uncertain linear systems with actuator failures within a prespecified subset of actuators. The uncertainty considered here is time- varying norm-bounded parameter uncertainty in the state matrix. The output of a faulty actuator is assumed to be any arbitrary energy-bounded signal. An observer-based output feedback controller design is presented which stabilizes the plant and guarantees an HH_{\infty }-norm bound on attenuation of augmented disturbances, for all admissible uncertainties as well as actuator failures. The construction of the observer-based output feedback control law requires the positive-definite solutions of two algebraic Riccati equations. The result can be regarded as an extension of existing results on robust HH_{\infty } control and reliable HH_{\infty } control of uncertain linear systems

    How Does Corporate Social Responsibility Promote Innovation? The Sequential Mediating Mechanism of Employees’ Meaningfulness of Work and Intrinsic Motivation

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    Based on group creativity framework, our research investigates how corporate social responsibility (CSR) promotes innovation of firms by revealing sequential mediating mechanisms of employee’s meaningfulness of work and intrinsic motivation. By applying a multi-level approach, this study examines the internal processes of micro-level variables between two macro-level variables (i.e., CSR and innovation). Utilizing a 3-wave longitudinal data from 4,178 organizational members in 502 branches as well as objective CSR records from one of the largest Korean commercial banks, we found that employee’s meaningfulness of work and intrinsic motivation sequentially mediate the CSR-innovation link. The results suggest that CSR functions as a powerful driver of innovation through enhancing employees’ perceptions and attitudes toward their job

    Substroke Matching by Segmenting and Merging for Online Korean Cursive Character Recognition

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    The Korean character is composed of several alphabets in two-dimensional formation and the total number of Korean characters exceeds eleven thousand. Therefore, the previous approaches to Korean cursive characters pay most of their attention to segmenting a character into alphabets accurately. However, it is difficult because the boundaries of alphabets are not apparent in most cases. We propose an alphabet-based method without assuming accurate alphabet segmentation. In the proposed method, a cursive character is segmented into substrokes by a set of segmenting conditions. Then it is matched with the reference substrokes generated from alphabet models and ligatures by segmenting and merging in the process of recognition. Among substrokes, a certain substroke can be either an alphabet itself a part of alphabet or a composite of the alphabet and ligature. We applied the proposed method to 5000 Korean characters and got the result of 83.4% for the first rank and 89.2% for the top 5 result candidates with the speed of 0.17 seconds on average per character on a PC which uses Intel Pentium 90 Mhz CPU

    A New pH-ISFET Based Dissolved Oxygen Sensor

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    A new dissolved oxygen sensor based on pH-ISFET has been discussed. A platinum working electrode surrounding a pH-sensing gate of the pH-ISFET electrolyzes dissolved oxygen, resulting in a corresponding pH change. The pH-ISFET can determine dissolved oxygen concentration through detecting this pH change. --Summar

    Temperature-dependent evolutions of excitonic superfluid plasma frequency in a srong excitonic insulator candidate, Ta2_2NiSe5_5

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    We investigate an interesting anisotropic van der Waals material, Ta2_{2}NiSe5_{5}, using optical spectroscopy. Ta2_{2}NiSe5_{5} has been known as one of the few excitonic insulators proposed over 50 years ago. Ta2_{2}NiSe5_{5} has quasi-one dimensional chains along the aa-axis. We have obtained anisotropic optical properties of a single crystal Ta2_{2}NiSe5_{5} along the aa- and cc-axes. The measured aa- and cc-axis optical conductivities exhibit large anisotropic electronic and phononic properties. With regard to the aa-axis optical conductivity, a sharp peak near 3050 cm1^{-1} at 9 K, with a well-defined optical gap (ΔEI\Delta^{EI} \simeq 1800 cm1^{-1}) and a strong temperature-dependence, is observed. With an increase in temperature, this peak broadens and the optical energy gap closes around \sim325 K(TcEIT_c^{EI}). The spectral weight redistribution with respect to the frequency and temperature indicates that the normalized optical energy gap (ΔEI(T)/ΔEI(0)\Delta^{EI}(T)/\Delta^{EI}(0)) is 1(T/TcEI)21-(T/T_c^{EI})^2. The temperature-dependent superfluid plasma frequency of the excitonic condensation in Ta2_{2}NiSe5_{5} has been determined from measured optical data. Our findings may be useful for future research on excitonic insulators.Comment: 17 pages, 5 figure

    On-Line Cursive Korean Character Recognition by using Curvature Models

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    A cursive Korean character consists of several Korean alphabets where connection is present within and among the alphabets. Recognition of Korean characters can be carried out by splitting each character into smaller primitives. Small line segments can be used as the primitives. But this approach requires too much processing time, for there can be many candidate references to be matched to one input character and each reference usually consists of too many primitives. In this paper, we propose an approach using structural curvature models to overcome the difficulties of using small line segments. These models are obtained by segmenting the input character at the points showing sudden change in direction, excessive rotation, etc. By doing this, rather larger and structural curve segments can be used as the basic primitives to be matched resulting in the savings of processing time and better recognition rat
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