• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.8
• /
• pp.60-68
• /
• 2008

The complex permittivity and permeability of various periodic metamaterial (MTM) cells are extracted by simulating a fictitious rectangular waveguide consisting of PEC and PMC walls. The shapes of the MTM cells include a thin wire (TW), a single split-ring resonator (SSRR), a double SRR (DSRR), a modified SRR, and a combined structure of the TW and the DSRR. The TW falls on a negative-$\varepsilon$/positive-$\mu$ region, the SRRs on a positive-$\varepsilon$/negative-$\mu$ region, and the combined structure on a negative-$\varepsilon$/negative-$\mu$ region. We also investigate how the permeability and permeability are affected by the dimension parameters of the MTM cells. Another extraction technique utilizing time domain signals is developed overcoming some limitations that the waveguide technique can not handle.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.10
• /
• pp.4563-4566
• /
• 2016

Background/Objective: The aim of this study was to perform a comparative evaluation of the yields of conventional brush cytology and brush cytology with negative pressure in the diagnosis of malignant biliary strictures. Methods: A total of 132 consecutive patients undergoing endoscopic were identified. Of these, 88.0 had brush cytology after ERCP and 44 were Brush cytology with negative pressure. Retrograde cholangiopancreatography (ERCP) including brush cytology and brush cytology with negative pressure in patients with biliary strictures between 2012-2015. Endoscopic retrograde cholangiography was performed with a standard videoduodenoscope Olympus TFJ 160-R (Olympus, Hamburg, Germany) and brush cytology with a Cook medical Double Lumen Biliary BrushTM (Cytology). Means and standard frequencies were used to calculate variables. Results: Positive results for malignancy were obtained in 22 of 88 patients (25%) by brush cytology and 31 of 44 patients (70.4 %) by brush cytology with negative pressure. Conclusions: Sensitivity of cytology sampling could be maximized by negative pressure during ERCP.

• Journal of Power Electronics
• /
• v.17 no.1
• /
• pp.262-271
• /
• 2017

This paper studies the performances of five typical Phase-locked Loops (PLLs) for distorted and unbalanced grid, which are the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL), Double Second-Order Generalized Integrator PLL (DSOGI-PLL), Double Second-Order Generalized Integrator Frequency-Lock Loop (DSOGI-FLL), Double Inverse Park Transformation PLL (DIPT-PLL) and Complex Coefficient Filter based PLL (CCF-PLL). Firstly, the principles of each method are meticulously analyzed and their unified small-signal models are proposed to reveal their interior relations and design control parameters. Then the performances are compared by simulations and experiments to investigate their dynamic and steady-state performances under the conditions of a grid voltage with a negative sequence component, a voltage drop and a frequency step. Finally, the merits and drawbacks of each PLL are given. The compared results provide a guide for the application of current control, low voltage ride through (LVRT), and unintentional islanding detection.

• Korean Journal of Applied Biomechanics
• /
• v.20 no.3
• /
• pp.311-318
• /
• 2010

This study examined the double piked dismount among the landing techniques of parallel bars based on three-dimensional motion analysis. Four male national gymnasts were the subjects. This study was performed to provide quantitative data highlighting players strengths and weaknesses to enable more stable landing technique. The variables analyzed were the position and velocity of center of gravity(CG) and angles of shoulder joints, hip joints, and trunk. The results are as follows: S1 secured the height of flight with fast vertical rise. After the easy spin in the air, he conducted a stable landing maintaining a proper hip joints angle. S2, S3, and S4, however, began the backward somersault already before leaving the bars, so they moved backward greatly making it more difficult to achieve a higher flight path. As a result, they couldn't control the velocity of their backward movement at landing. For a stable landing, they have to maintain the negative shoulder angle when rising, minimize both antero-posterioror side-to-side movements by doing a strong tap using hip joints, to secure the height of flight before the somersault. Results also show that at the descent, they should conduct rapid spinning by increasing their shoulder and hip joints to the maximum while controlling their velocity.

• Steel and Composite Structures
• /
• v.41 no.5
• /
• pp.649-661
• /
• 2021

This paper presents experimental and analytical studies to understand the behavior of crumb rubber concrete (CRC)-filled fiber reinforced polymer (FRP) and steel tube double skin column (DSC) and beam (DSB) members under cyclic loading. The main test variable was the percentage of rubber which ranged from 0 to 40%. For column members, different heights corresponding to different aspect ratios were examined to understand the to understand the effect of DSCs' slenderness on the cyclic response of the columns. the. The behavior of the specimens in terms of failure mode, strain development, energy dissipation, load-displacement response were presented and compared. The ability of the current provisions of the Australian codes to predict the capacity of such double skin members was also evaluated based on the test results. This study concluded that the reduction in the concrete strength was more severe at the material level compared to structural level. Also, as the load changed from axial compression in columns to pure moment in beams the negative effect of rubber percentage on the strength became less significant.

• Industry Promotion Research
• /
• v.8 no.3
• /
• pp.51-60
• /
• 2023

The purpose of this study was to verify the double mediating effects of job stress and psychological commitment in the relationship between organizational incivility and job satisfaction of child-care teachers in South Korea. 234 Korean child-care teachers were purposively selected from S city of C Province. SPSS Win.25.0 and PROCESS Macro 4.2 were used for analyzing the data, and reliability analysis, frequency analysis, correlation analysis, and multiple mediation model analysis were conducted. Results are as follows. First, correlation analysis showed significant correlations between organizational incivility, job stress, psychological commitment, and job satisfaction. Second, path analysis showed that organizational incivility had a positive effect on job stress and a negative effect on psychological commitment and job satisfaction. Job stress had a negative and significant effect on psychological commitment and job satisfaction, and psychological commitment had a positive and significant effect on job satisfaction. Third, job stress and psychological commitment had consecutive double mediation in the link between organizational incivility and job satisfaction. This study suggests a way to utilize job stress and psychological commitment when childcare teachers' organizational incivility has a negative effect on job satisfaction.

• Journal of the Korean Electrochemical Society
• /
• v.6 no.2
• /
• pp.153-157
• /
• 2003

A hybrid electrochemical capacitor having both characteristics of electric double layer capacitance and pseudo-capacitance was studied throughout cell tests. Asymmetric electrodes with $Ni(OH)_2/activated$ carbon based positive electrode and activated carbon based negative electrode were used in preparing test cells of $5\times5cm^2$. Cyclic voltammetry measurements and impedance measurements were conducted to understand electrochemical behavior of each electrode. To find an optimal mass ratio of negative to positive electrode, charge-discharge cycle tests were also performed.

• The Korean Journal of Applied Statistics
• /
• v.22 no.6
• /
• pp.1289-1300
• /
• 2009

The double sampling scheme is effective in reducing the sampling cost. However, the doubly sampled data is contaminated by two types of error, namely false-positive and false-negative errors. These would make the statistical analysis more difficult, and it would require more sophisticate analysis tools. For instance, the Wald method for the interval estimation of a proportion would not work well. In fact, it is well known that the Wald confidence interval behaves very poorly in many sampling schemes. In this note, the property of the Wald interval is investigated in terms of the coverage probability and the expected width. An alternative confidence interval based on the Agresti-Coull's approach is recommended.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.3
• /
• pp.701-712
• /
• 2016

The purpose of this study was to investigate the effect of democratic and autocratic behavior type of dance art instructors in elementary dance education on class satisfaction focused on mediations of flow and perceived competence. A total of 500 questionnaires were distributed but insincerely replied or double-replied questionnaires were excluded and finally 453 questionnaires were analyzed for this study. For the analysis of the data, SPSS 18.0 version was used and double mediation model operating in serial, proposed by Hayes and a bootstrapping method were used. First, instructor's democratic behavior type was statistically positive effect on class satisfaction. However autocratic behavior type was statistically negative effect. Second, the indirect effect of instructor's democratic type and autocratic behavior type on class satisfaction through the flow were statistically positive significant. Third, the indirect effect of instructor's democratic behavior type on class satisfaction through the perceived competence was statistically significant. However autocratic behavior type was statistically negative effect. Lastly, the indirect effect of instructor's democratic and autocratic behavior types on class satisfaction through the flow and perceived competence were statistically positive significant.

• The Korean Journal of Applied Statistics
• /
• v.16 no.2
• /
• pp.335-349
• /
• 2003

In this paper, we use Bayesian method for model selection of poisson vs. negative binomial distribution, and normal, double exponential vs. cauchy distribution. The fractional Bayes factor of O'Hagan (1995) was applied to Bayesian model selection under the assumption of noninformative improper priors for all parameters in the models. Through the analyses of real data and simulation data, we examine the usefulness of the fractional Bayes factor in comparison with intrinsic Bayes factors of Berger and Pericchi (1996, 1998).