• Title/Summary/Keyword: anti-bias

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A new magnetic sensor for the non-contact measurement of bending vibrations of non-ferromagnetic pipes (비자성 배관의 비접촉 굽힘 진동 측정을 위한 자기 센서의 개발)

  • Han, Soon-Woo;Kim, Yoon-Young
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1154-1158
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    • 2006
  • This investigation suggests a new non-contact type sensor that can measure flexural vibrations of a non-ferromagnetic pipe. The sensor works on the reversed Lorentz force mechanism; however, anti-symmetric bias magnetic field suggested in this work should be applied to measure bending vibration of a non-ferromagnetic pipe. The importance of the suggested magnetic field is verified by a series of experiments. The sensor is applied to the bending vibration measurement and modal testing of an aluminum pipe and shows satisfactory working performance compared to others.

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Practical Pinch Torque Detection Algorithm for Anti-Pinch Window Control System Application

  • Lee, Hye-Jin;Ra, Won-Sang;Yoon, Tae-Sung;Park, Jin-Bae
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2526-2531
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    • 2005
  • A practical pinch torque estimator based on the Kalman filter is proposed for low-cost anti-pinch window control systems. To obtain the accurate angular velocity from Hall-effect sensor measurements, the angular velocity calculation algorithm is executed with additional procedures for removing the measurement noises. Apart from the previous works using the angular velocity estimates and torque estimates for detecting the pinched condition, the torque rate is augmented to the system model and the proposed pinch estimator is derived by applying the steady-state Kalman filter recursion to the model. The motivation of this approach comes from the idea that the bias errors in torque estimates due to the motor parameter uncertainties can be almost eliminated by introducing the torque rate state. For detecting the pinched condition, a systematic way to determine the threshold level of the torque rate estimates is also suggested via the deterministic estimation error analysis. Simulation results are given to certify the pinch detection performance of the proposed algorithm and its robustness against the motor parameter uncertainties.

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A meta analysis for anti-hyperlipidemia effect of soybeans (메타분석을 이용한 대두의 항-고지혈 효과)

  • Kim, Ji-Eun;Choi, Ki-Heon
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.4
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    • pp.651-667
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    • 2010
  • In this paper, using a meta analysis of anti-hyperlipidemia effect of soybeans were studied. Studied the effects of soybeans using Hedges' standardized mean difference looked at the effect. Applying the fixed-effects model analysis of fecal cholesterol and total cholesterol and triglycerides showed a statistically significant reduction in HDL cholesterol increase was statistically significant at. In addition, the homogeneity of all variables by running the test did not meet the homogeneity of the kidney weight, between weight, HDL cholesterol, LDL cholesterol, total cholesterol, and triglycerides in the random effects model against the results of the analysis conducted by a statistically significant variable that did not.

77 GHz Waveguide VCO for Anti-collision Radar Applications (차량 충돌 방지 레이더 시스템 응용을 위한 77 GHz 도파관 전압 조정 발진기)

  • Ryu, Keun-Kwan;Kim, Sung-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.7
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    • pp.1652-1656
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    • 2014
  • In this work, we demonstrated a 77 GHz waveguide VCO with transition from WR-12 to WR-10 for anti-collision radar applications. The fabricated waveguide VCO consists of a GaAs-based Gunn diode, a varactor diode, a waveguide transition, and two bias posts for operating as a LPF and a resonator. The cavity is designed for fundamental mode at 38.5 GHz and operated at second hormonic of 77 GHz. The waveguide transition has a 1.86 dB of insertion loss and -30.22 dB of S11 at the center frequency of 77 GHz. The fabricated VCO achieves an oscillation bandwidth of 870 MHz. Output power is from 12.0 to 13.75 dBm and phase noise is -100.78 dBc/Hz at 1 MHz offset frequency from the carrier.

Effect of anti-rheumatic agents on periodontal parameters and biomarkers of inflammation: a systematic review and meta-analysis

  • Han, Ji-Young;Reynolds, Mark A.
    • Journal of Periodontal and Implant Science
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    • v.42 no.1
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    • pp.3-12
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    • 2012
  • Purpose: Anti-rheumatic agents target common molecular pathways of inflammation in rheumatoid arthritis (RA) and periodontitis. The purpose of this study was to determine the relative effect of anti-rheumatic agents on the levels of inflammatory biomarkers and periodontal inflammation in RA patients with periodontitis. Methods: A systematic review and meta-analysis were conducted of studies comparing periodontal parameters of inflammation, such as bleeding on probing, and biomarkers of inflammation in RA patients with periodontitis and healthy adults with and without periodontitis. The search included the electronic databases MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar, inclusive through October 2011, with no language restrictions. Hand searches were conducted of the bibliographies of related journals and systematic reviews. Observational and interventional studies assessing the effects of antirheumatic therapy qualified for inclusion. Two reviewers performed independent data extraction and risk-of-bias assessment. Of the 187 identified publications, 13 studies fulfilled the inclusion criteria. Results: When compared to healthy adults without periodontitis, RA subjects were found to have significantly higher levels of bleeding on probing and limited evidence of higher levels of interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in gingival crevicular fluid and saliva. No consistent differences were found in periodontal parameters and inflammatory biomarkers between RA subjects and adults with periodontitis. Studies evaluating the effect of anti-TNF-${\alpha}$ therapy in RA subjects with periodontitis have yielded inconsistent results. Conclusions: There are limited data, however, to suggest that anti-TNF-${\alpha}$ agents can reduce local production of inflammatory cytokines and periodontal inflammation in RA patients with periodontitis.

A Fabrication and Characteristics of 16x8 Reflection Type Symmetric Self Electro-optic Effect Device Array (16x8 반사형 S-SEED 어레이 제작 및 특성)

  • 김택무;이승원;추광욱;김석태;정문식;김성우;권오대;강봉구
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.10
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    • pp.33-40
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    • 1993
  • A reflection type 16x8 S-SEED array from LP(Low Pressure)-MODVD-grown GaAs/AlGaAs extremely shallow quantum well(ESQW) structures, with 4% Al fraction, has been fabricated. Its intrinsic region consists of 50 pairs of alternating 100.angs. GaAs and 100.angs. $Al_{0.04}$Ga$_{0.96}$As layers. A multilayer reflector stack of $Al_{0.04}$/Ga$_{0.96}$ As(599$\AA$)/AlAs(723$\AA$) was incorporated for the reflection plane below the p-i-n structures. The device processing after the MOCVD growth includes the mesa etching, isolation etching, insulator deposition, p & n metallization, and AR(Anti-Reflection) coating. For switching characteristics of the S-SEED in the form of p-i-n ESQW diode, the maximum optical negative resistance was observed at 856nm. Reflectance measurements showed a change from 15.6% to 43.3% for +0.9V to -6V bias. The maximum contrast ration of the S-SEED array was 2.0 and all the 128 devices showed optical bistability with contrast ratios over 2.4 at 5V reverse bias.

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High rate deposition and mechanical properties of SiOx film on PET and PC polymers by PECVD with the dual frequencies UHF and HF at low temperature

  • Jin, Su-B.;Choi, Yoon-S.;Choi, In-S.;Han, Jeon-G.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.180-180
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    • 2010
  • The design and implementation of high rate deposition process and anti-scratch property of silicon oxide film by PECVD with UHF power were investigated according to the effect of UHF input power with HF bias. New regime of high rate deposition of SiOx films by hybrid plasma process was investigated. The dissociation of OMCTS (C8H24Si4O4) precursor was controlled by plasma processes. SiOx films were deposited on polyethylene terephthalate (PET) and polycarbonate substrate by plasma enhanced chemical vapor deposition (PECVD) using OMCTS with oxygen carrier gas. As the input energy increased, the deposition rate of SiOx film increased. The plasma diagnostics were performed by optical emission spectrometry. The deposition rate was characterized by alpha-step. The mechanical properties of the coatings were examined by nano-indenter and pencil hardness, respectively. The deposition rate of the SiOx films could be controlled by the appropriate intensity of excited neutrals, ionized atoms and UHF input power with HF bias at room temperature, as well as the dissociation of OMCTS.

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A Study on the Glow Discharge Characteristics of MgO thin film prepared by Unbalanced Magnetron Sputtering (불평형 마그네트론 스파터링에 의해 형성된 MgO 박막의 글로우 방전특성에 관한 연구)

  • Kim, Young-Kee;Park, Jung-Tae;Ko, Kwang-Sic;Kim, Gyu-Seup;Park, Chung-Hoo;Cho, Jung-Soo
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2236-2238
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    • 1999
  • This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by RF unbalanced magnetron sputtering(UBMS) in surface discharge type AC PDP. The minimum discharge voltage is obtained for the sample of substrate holder bias voltage -10V. The main factors that improves the discharge characteristics by applied bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardment during deposition process Moreover, the anti-sputtering characteristics of MgO thin film by UBMS is more excellent than that of balanced magnetron sputtering(BMS) and E-beam evaporation method.

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On Mode Correlation of Solar Acoustic Oscillations

  • Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
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    • v.26 no.3
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    • pp.287-294
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    • 2009
  • In helioseismology it is normally assumed that p-mode oscillations are excited in a statistically independent fashion. Unfortunately, however, this issue is not clearly settled down in that two experiments exist, which apparently look in discrepancy. That is, Appourchaux et al. (2000) looked at bin-to-bin correlation and found no evidence that the assumption is invalid. On the other hand, Roth (2001) reported that p-mode pairs with nearby frequencies tend to be anti-correlated, possibly by a mode-coupling effect. This work is motivated by an idea that one may test if there exists an excess of anticorrelated power variations of pairs of solar p-modes. We have analyzed a 72-day MDI spherical-harmonic time series to examine temporal variations of p-mode power and their correlation. The power variation is computed by a running-window method after the previous study by Roth (2001), and then distribution function of power correlation between mode pairs is produced. We have confirmed Roth's result that there is an excess of anti-correlated p-mode pairs with nearby frequencies. On the other hand, the amount of excess was somewhat smaller than the previous study. Moreover, the distribution function does not exhibit significant change when we paired modes with non-nearby frequencies, implying that the excess is not due to mode coupling. We conclude that the origin of this excess of anticorrelations may not be a solar physical process, by pointing out the possibility of statistical bias playing the central role in producing the excess.

Two-Stage Estimator Design Using Stable Recursive FIR Filter and Smoother

  • Kim, Jong-Ju;Kim, Jae-Hun;Lyou, Joon
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2532-2537
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    • 2005
  • FIR(Finite Impulse Response) filter is well known to be ideal for the finite time state-space model, but it requires much computation due to its inherent non-recursive structure especially when the measurement interval grows to a large extent. And often a fixed-lag smoother based on the finite time interval is needed to monitor the soundness of the system model and the measurement model, but the computation burden of FIR-type smoother imposes much restriction of its usage for real-time application. Conventional recursive forms of FIR estimator[1]-[4] could not be used for real time applications, since they are numerically unstable in their recursive equations. To cope with this problem, we suggest a stable recursive form FIR estimator(SRFIR) and its usefulness is demonstrated for designing the real-time fixed-lag smoother on the finite time window through an example of detection of rate bias in the anti-aircraft gun fire control system.

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