• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.235-246
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• 2004

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.05a
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• pp.156-157
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• 2001

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.117.2-118
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• 2003

Sample size calculations plays an important role in a bioequivalence trials and is determined by considering power under the alternative hypothesis. The regulatory guideline recommends that $2{\times}2$ crossover design is conducted and raw data is log-transformed for statistical analysis. In this paper, we discuss the sample size calculation in $2{\times}2$ crossover design with the log-transformed data.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.24-28
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• 2018

The redox flow battery (RFB) is a large-capacity energy storage equipment, and the vanadium redox flow cell is a typical RFB, but VRFB is expensive. Iron-chrome RFBs are economical because they use low-cost active materials, but their low performance is a urgent problem. In this study, the crossover of iron and chromium ion through Nafion membrane and the stability of Nafion membrane in HCl solution were investigated. The permeability of iron and chrome ion through Nafion were $5.5{\times}10^{-5}$ and $6.0{\times}10^{-5}cm^2/min$, respectively, which was 18.9~20.7 times higher than that of vanadium ion ($2.9{\times}10^{-6}cm^2/min$). The crossover of iron and chromium ions were shown to be a cause of performance decrease in Iron-chrome RFB. As the temperature increases, the crossover increases rapidly (activation energy 38.8 kJ/ mol), indicating that operation at low temperature is a methode to reduce the performance loss due to crossover. Nafion membranes were relatively stable in 3 M HCl solution.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.17-21
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• 2019

The redox flow battery (RFB) is a large-capacity energy storage equipment, and the vanadium redox flow cell is a typical RFB, but VRFB is expensive. Iron-chrome RFBs are economical because they use low-cost active materials, but their low performance is an urgent problem. One of the reasons for the low performance is the crossover of the active materials. In this study, the sulfonated Poly (ether ether ketone) (sPEEK) membrane, which is a hydrocarbon membrane, was used instead of the fluorine membrane to reduce the crossover of the active materials. The chromium ion permeability of the sPEEK membrane was $1.8{\times}10^{-6}cm^2/min$, which was about 1/33 of that of the Nafion membrane. Thus, it was shown that the use of the sPEEK membrane instead of the fluorine membrane could solve the high active material crossover problem. The activation energy of iron diffusion through the sPEEK membrane was 24.9 kJ/mol, which was about 66% of Nafion membrane. And that the e-PTFE support in the polymer membrane reduces the active material crossover through Iron-Chrome Redox Flow Battery (ICRFB).

• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.151-160
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• 2020

In the past, musicians followed strict patterns written by composers when playing classical music. However, since the development of postmodernism, which puts an emphasis on unique individualities and various ways of thinking, following the strict patterns of classical music unquestioningly became less significant. Classical music was thought to be difficult to follow and enjoy for most people. Thus, musicians have found ways to keep the dignity of classical music but added familiarity in order to popularize arias in operas. They created classical crossover music and this type of music enabled people to enjoy easy access to classical music. However, not many studies focus on arrangement methods of changing classical music into crossover music. The goal of this study is to research on arrangement methods of crossover music based on the findings from precedent researches on operas. This study focused on analyzing musical structure including chords, rhythms and compositions of musical instruments. According to the analysis, original classical songs and popera, which is a type of crossover music, share similarities in terms of rhythms and chords. However, there are differences when it comes to compositions of musical instruments. In case of a jazz version, it uses AfroCuban rhythm as well as Bolero rhythm which is a part of ballad and jazz acoustic instruments are mainly used. Also, in order to reduce the feeling of classical music and to differentiate the jazz version from the original version, a lot of tension is used in voicing. This study can be helpful for any researches related to arrangements of classical crossover music.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.161-167
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• 2011

The primary variables are often systematically related to other influences apart from drug effect. For instance, there may be relationships to covariates such as health conditions or prognostic factors. When a $2{\times}2$ crossover experiment for bioequivalence is designed, the statistical adjustment for the influence of covariates should be considered if some covariates influence the drug effect. Statistical inference for assessing average bioequivalence for a $2{\times}2$ crossover design with covariates is given and an illustrated example is presented with discussion.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.227-232
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• 2015

Nowadays, there are many innovative products in the pro-audio market thanks to advanced IT technology, DSP is very important technology to process high quality audio signal in SR(Sound Reinforcement) system. Digital audio technology that converged with IT technology can give new user-experience. In this paper, we present a new digital crossover system for active speakers using DSP and network technology. The prototype of crossover module consists of various audio process module such as filters, delay, phase controls and also it provides user to remote monitoring and remote control features by internet connection.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.534-537
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• 2010

A twenty six year old man was admitted to our clinic for bleeding from a venous ulcer of the left leg. His left femoral vein had been ligated for bleeding control after a traffic accident that happened when he was 5 years old. He had a varicose vein, stasis dermatitis, and a venous ulcer on his left leg. To shunt left femoral venous return to the right femoral vein, we did a crossover bypass with arteriovenous fistula using the right greater saphenous vein. To get good patency of the arteriovenous fistula, the bypass graft was closed 6 weeks after the initial operation. He maintained his left leg circumference relatively well for 6 months after the operation. We report the case of a patient who had a vein crossover bypass for a chronic femoral vein ligation.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.159-171
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• 2005

The US Food and Drug Administration(FDA) recommends that population bioequivalence and individual bioequivalence would be assessed to address the prescribability and switchability between a brand-name drug and its new formulation or generic copy in its 2001 guidance document. The test for population bioequivalence in the latest FDA guidance is recommended in 2 x 4 crossover design, but it turns out to be very conservative. Recently Lee, Shao & Chow(2002), Chow, Shao & Wang(2003) and McNally, Iyer & Mathew(2002) proposed new statistical methods for assessing population bioequivalence between drugs to correct the biasness of current FDA method. Since 2 x 2 crossover experiment is most welcomed design in bioequivalence testing, we adopt their methods to 2 x 2 crossover designs and compare their methodologies with FDA one through the simulation study.