• Title/Summary/Keyword: Velocity Bias

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Acupotomy for Carpal Tunnel Syndrome: A Systematic Review and Meta-Analysis (수근관증후군에 대한 도침치료의 효과: 체계적 문헌 고찰과 메타분석)

  • Jeong, Jae-Min;Sul, Jae-Uk;Kim, Seon-Jong;Seon, Yun-Gwon;Choi, Ji-Min;Noh, Hui-Jeong;Choi, Jin-Bong
    • Journal of Korean Medicine Rehabilitation
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    • v.32 no.3
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    • pp.55-64
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    • 2022
  • Objectives The objective of this study was to assess the effectiveness of acupotomy for carpal tunnel syndrome. Methods Based on seven domestic and foreign databases. We analyzed the randomized controlled trials using acupotomy for carpal tunnel syndrome. The treatment group was treated with acupotomy and the control group was no restrictions on treatment methods. Results In this study, the effect of acupuncture treatment for carpal tunnel syndrome was investigated. Each study reported that acupotomy could be an effective treatment for carpal tunnel syndrome. However, as a result of meta-analysis of Levine carpal tunnel syndrome questionnaire scores, visual analog scale, and sensory nerve conduction velocity, the results were more clinically significant than those of the control group. Due to the small number of randomized controlled trial studies and the nature of acupotomy treatment, blinding of interventions was impossible, resulting in a high risk of bias. Conclusions In this regard, it is thought that well-planned randomized controlled studies on patients with carpal tunnel syndrome are needed in the future to secure the clinical evidence for acupotomy treatment.

Numerical Analysis on Thermal-Induced Degradation of n-i-p Structure Perovskite Solar Cells Using SCAPS-1D (SCAPS-1D 시뮬레이션을 이용한 n-i-p 구조 페로브스카이트 태양전지의 열적 열화 원인 분석)

  • Kim, Seongtak;Bae, Soohyun;Jeong, Younghun;Han, Dong-Woon;Kim, Donghwan;Mo, Chan Bin
    • Current Photovoltaic Research
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    • v.10 no.1
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    • pp.16-22
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    • 2022
  • The long-term stability of PSCs against visual and UV light, moisture, electrical bias and high temperature is an important issue for commercialization. In particular, since the operation temperature of solar cell can rise above 85℃, a study on thermal stability is required. In this study, the cause of thermal-induced degradation of PSCs was investigated using the SCAPS-1D simulation tool. First, PSCs of TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au structure were exposed to a constant temperature of 85℃ to observe changes in conversion efficiency and quantum efficiency. Because the EQE reduction above 500 nm was remarkable, we simulated PSCs performance as a function of lifetime, doping density of perovskite and spiro-OMeTAD. Consequently, the main cause of thermal-induced degradation is considered to be the change in the perovskite doping concentration and lifetime due to ion migration of perovskite.

A Simple Test for Optimal Fiscal and Monetary Policy Regimes: The Case of Korea (재정(財政)·통화정책(通貨政策)의 적정관계(適正關係)에 대한 고찰(考察) : 재정우위(財政優位)모델에 의한 실증적(實證的) 분석(分析))

  • Whang, Seong-hyeon
    • KDI Journal of Economic Policy
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    • v.13 no.4
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    • pp.141-153
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    • 1991
  • The optimal choice of the tax rate and the inflation rate framework is extended to yield relevant interpretations for the optimal fiscal and monetary policy regime in Korea. To study the relationship between the government budget and monetary growth in different environments of policy coordination, two models assuming different degrees of fiscal dominance are developed. By modelling differing institutional arrangements of the fiscal and the monetary authority from an optimal government finance viewpoint, we find the optimal relationship among some important fiscal and monetary variables. By testing the existence of the relationship empirically, we find the characteristics of the optimal policy-mix regime in Korea. The first model-the strong from of fiscal dominance-studies the optimal collection of seigniorage in a period-by-period optimization with standard assumptions on the income velocity of money, deriving a general testable result: the optimal inflation/tax rate ratio co-vary with the marginal revenue ratio. The second model-the weak form of fiscal dominance-studies an implication of the inflationary bias of discretionary monetary policy in the presence of fiscal side distortions. This model shows that the tax rate and the inflation rate can have a positive correlation. Empirical tests of the theoretical results are done for the Korean economy for 1972-1989 period. The test results show that the macroeconomic policy regime in Korea can be characterized by the strong form of fiscal dominance, implying the importance of the government budget in explaining money growth and inflation.

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Effects of Parameters Defining the Characteristics of Raindrops in the Cloud Microphysics Parameterization on the Simulated Summer Precipitation over the Korean Peninsula (구름미세물리 모수화 방안 내 빗방울의 특성을 정의하는 매개변수가 한반도 여름철 강수 모의에 미치는 영향)

  • Ki-Byung Kim;Kwonil Kim;GyuWon Lee;Kyo-Sun Sunny Lim
    • Atmosphere
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    • v.34 no.3
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    • pp.305-317
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    • 2024
  • The study examines the effects of parameters that define the characteristics of raindrops on the simulated precipitation during the summer season over Korea using the Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) cloud microphysics scheme. Prescribed parameters, defining the characteristics of hydrometeors in the WDM6 scheme such as aR, bR, and fR in the fall velocity (VR) - diameter (DR) relationship and shape parameter (𝜇R) in the number concentration (NR) - DR relationship, presents different values compared to the observed data from Two-Dimensional Video Disdrometer (2DVD) at Boseong standard meteorological observatory during 2018~2019. Three experiments were designed for the heavy rainfall event on August 8, 2022 using WRF version 4.3. These include the control (CNTL) experiment with original parameters in the WDM6 scheme; the MUR experiment, adopting the 50th percentile observation value for 𝜇R; and the MEDI experiment, which uses the same 𝜇R as MUR, but also includes fitted values for aR, bR, and fR from the 50th percentile of the observed VR - DR relationship. Both sensitivity experiments show improved precipitation simulation compared to the CNTL by reducing the bias and increasing the probability of detection and equitable threat scores. In these experiments, the raindrop mixing ratio increases and its number concentration decreases in the lower atmosphere. The microphysics budget analysis shows that the increase in the rain mixing ratio is due to enhanced source processes such as graupel melting, vapor condensation, and accretion between cloud water and rain. Our study also emphasizes that applying the solely observed 𝜇R produces more positive impact in the precipitation simulation.

An Analysis on Characteristics of Turbulence Energy Dissipation Rate from Comparison of Wind Profiler and Rawinsonde (연직바람관측장비와 레윈존데의 비교를 통한 난류 에너지 감소률의 특성 분석)

  • Kang, Woo Kyeong;Moon, Yun Seob;Jung, Ok Jin
    • Journal of the Korean earth science society
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    • v.37 no.7
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    • pp.448-464
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    • 2016
  • The purpose of this study is to optimize the parameters related to consensus coherency within the PCL 1300, the operating program of wind profiler, from a validation of wind data between rawinsonde and wind profiler at Chupungryeong ($36^{\circ}13^{\prime}$, $127^{\circ}59^{\prime}$) site in Korea. It is then to analyze the diurnal and seasonal characteristics of the turbulence energy dissipation rate (${\varepsilon}$) in clear and rainy days from March 2009 to February 2010. In comparison of the wind data between wind profiler and rawinsonde during April 22-23, 2010, it was shown in a big error more than $10ms^{-1}$ over the height of 3,000 meters in the zonal (u) and meridional (v) wind components. When removing more than $10ms^{-1}$ in each wind speed difference of u an v components between the two instruments, the correlation coefficients of these wind components were 0.92 and 0.88, respectively, and the root mean square errors were 3.07 and $1.06ms^{-1}$. Based on these results, when the data processing time and the minimum available data within the PCL 1300 program were adjusted as 30 minutes and 60%, respectively, the bias errors were small. In addition, as a result of an analysis of sensitivity to consensus coherency of u and v components within the PCL1300 program, u components were underestimated in radial coherency, instantaneous and winbarbs coherency, whereas v components were overestimated. Finally by optimizing parameters of the PCL1300 program, the diurnal and seasonal means of ${\varepsilon}$ at each height were higher in rainy days than those in clear days because of increasing in the vertical wind speed due to upward and downward motions. The mean ${\varepsilon}$ for clear and rainy days in winter was lower than those of other seasons, due to stronger horizontal wind speed in winter than those in other seasons. Consequently, when the turbulence energy dissipation rates in the vertical wind speed of more than ${\pm}10cm\;s^{-1}$ were excluded for clear and rainy days, the mean ${\varepsilon}$ in rainy days was 6-7 times higher than that in clear days, but when considering them, it was 4-5 times higher.

THE LUMINOSITY-LINEWIDTH RELATION AS A PROBE OF THE EVOLUTION OF FIELD GALAXIES

  • GUHATHAKURTA PURAGRA;ING KRISTINE;RIX HANS-WALTER;COLLESS MATTHEW;WILLIAMS TED
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.63-64
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    • 1996
  • The nature of distant faint blue field galaxies remains a mystery, despite the fact that much attention has been devoted to this subject in the last decade. Galaxy counts, particularly those in the optical and near ultraviolet bandpasses, have been demonstrated to be well in excess of those expected in the 'no-evolution' scenario. This has usually been taken to imply that galaxies were brighter in the past, presumably due to a higher rate of star formation. More recently, redshift surveys of galaxies as faint as B$\~$24 have shown that the mean redshift of faint blue galaxies is lower than that predicted by standard evolutionary models (de-signed to fit the galaxy counts). The galaxy number count data and redshift data suggest that evolutionary effects are most prominent at the faint end of the galaxy luminosity function. While these data constrain the form of evolution of the overall luminosity function, they do not constrain evolution in individual galaxies. We are carrying out a series of observations as part of a long-term program aimed at a better understanding of the nature and amount of luminosity evolution in individual galaxies. Our study uses the luminosity-linewidth relation (Tully-Fisher relation) for disk galaxies as a tool to study luminosity evolution. Several studies of a related nature are being carried out by other groups. A specific experiment to test a 'no-evolution' hypothesis is presented here. We have used the AUTOFIB multifibre spectro-graph on the 4-metre Anglo-Australian Telescope (AAT) and the Rutgers Fabry-Perot imager on the Cerro Tolalo lnteramerican Observatory (CTIO) 4-metre tele-scope to measure the internal kinematics of a representative sample of faint blue field galaxies in the red-shift range z = 0.15-0.4. The emission line profiles of [OII] and [OIII] in a typical sample galaxy are significantly broader than the instrumental resolution (100-120 km $s^{-l}$), and it is possible to make a reliable de-termination of the linewidth. Detailed and realistic simulations based on the properties of nearby, low-luminosity spirals are used to convert the measured linewidth into an estimate of the characteristic rotation speed, making statistical corrections for the effects of inclination, non-uniform distribution of ionized gas, rotation curve shape, finite fibre aperture, etc.. The (corrected) mean characteristic rotation speed for our distant galaxy sample is compared to the mean rotation speed of local galaxies of comparable blue luminosity and colour. The typical galaxy in our distant sample has a B-band luminosity of about 0.25 L$\ast$ and a colour that corresponds to the Sb-Sd/Im range of Hub-ble types. Details of the AUTOFIB fibre spectroscopic study are described by Rix et al. (1996). Follow-up deep near infrared imaging with the 10-metre Keck tele-scope+ NIRC combination and high angular resolution imaging with the Hubble Space Telescope's WFPC2 are being used to determine the structural and orientation parameters of galaxies on an individual basis. This information is being combined with the spatially resolved CTIO Fabry-Perot data to study the internal kinematics of distant galaxies (Ing et al. 1996). The two main questions addressed by these (preliminary studies) are: 1. Do galaxies of a given luminosity and colour have the same characteristic rotation speed in the distant and local Universe? The distant galaxies in our AUTOFIB sample have a mean characteristic rotation speed of $\~$70 km $s^{-l}$ after correction for measurement bias (Fig. 1); this is inconsistent with the characteristic rotation speed of local galaxies of comparable photometric proper-ties (105 km $s^{-l}$) at the > $99\%$ significance level (Fig. 2). A straightforward explanation for this discrepancy is that faint blue galaxies were about 1-1.5 mag brighter (in the B band) at z $\~$ 0.25 than their present-day counterparts. 2. What is the nature of the internal kinematics of faint field galaxies? The linewidths of these faint galaxies appear to be dominated by the global disk rotation. The larger galaxies in our sample are about 2"-.5" in diameter so one can get direct insight into the nature of their internal velocity field from the $\~$ I" seeing CTIO Fabry-Perot data. A montage of Fabry-Perot data is shown in Fig. 3. The linewidths are too large (by. $5\sigma$) to be caused by turbulence in giant HII regions.

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