• Nutrition Research and Practice
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• v.17 no.4
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• pp.789-802
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• 2023

BACKGROUND/OBJECTIVES: Habitual coffee consumption was inversely associated with type 2 diabetes (T2D) and hyperglycemia in observational studies, but the causality of the association remains uncertain. This study tested a causal association of genetically predicted coffee consumption with T2D using the Mendelian randomization (MR) method. SUBJECTS/METHODS: We used five single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) associated with habitual coffee consumption in a previous genome-wide association study among Koreans. We analyzed the associations between IVs and T2D, fasting blood glucose (FBG), 2h-postprandial glucose (2h-PG), and glycated haemoglobin (HbA1C) levels. The MR results were further evaluated by standard sensitivity tests for possible pleiotropism. RESULTS: MR analysis revealed that increased genetically predicted coffee consumption was associated with a reduced prevalence of T2D; ORs per one-unit increment of log-transformed cup per day of coffee consumption ranged from 0.75 (0.62-0.90) for the weighted mode-based method to 0.79 (0.62-0.99) for Wald ratio estimator. We also used the inverse-variance-weighted method, weighted median-based method, MR-Egger method, and MR-PRESSO method. Similarly, genetically predicted coffee consumption was inversely associated with FBG and 2h-PG levels but not with HbA1c. Sensitivity measures gave similar results without evidence of pleiotropy. CONCLUSIONS: A genetic predisposition to habitual coffee consumption was inversely associated with T2D prevalence and lower levels of FBG and 2h-PG profiles. Our study warrants further exploration.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.356-363
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• 2020

As a becoming era of Internet-of-Things, various devices are connected via wire or wirless networks. Although every day life is more convenient, security problems are also increasing such as privacy, information leak, denial of services. Since ECC, a kind of public key cryptosystem, has a smaller key size compared to RSA, it is widely used for environmentally constrained devices. The key of ECC in constrained devices can be exposed to power analysis attacks during scalar multiplication operation. In this paper, a key-randomization method is suggested for scalar multiplication on SECG parameters. It is against differential power analysis and has operational efficiency. In order to increase of operational efficiency, the proposed method uses the property 2^lP=∓cP where the constant c is small compared to the order n of SECG parameters and n=2^l±c. The number of operation for the Coron's key-randomization scalar multiplication algorithm is 21, but the number of operation for the proposed method in this paper is (3/2)l. It has efficiency about 25% compared to the Coron's method using full random numbers.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.525-537
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• 2001

In this paper a new space vector RPPWM(Random Position PWM) is proposed. In the propsed RPPWM each of three phase pulses is located randomly in each switching interval. Based on the Space vector modulation technique the duty ratio of the pulses is calculated Along with the randomization of the PWM pulses. we can obtain the effects of spread spectra of votlage, current as in the case of randomly changed switching frequency, To verify the validity of the proposed RPPWM simulation study was tried using Matlab/Simulink The main model described in Simulink block diagrams includes the space vector modulation block pulse position randomization block inverter block 3 phase induction motor block and so on By the simulation study, the harmonics of the output voltage and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM proposed RPPWM.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.387-398
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• 2002

In this paper, a new Three-Phase Lead-Lag Random Pulse Position PWM(LL-RPWM) scheme is proposed and implemented for decreasing audible acoustic noise of motor drives. In the proposed RPWM(Random PWM), each of three phase pulses is located randomly in each switching interval. Based on the space vector modulation technique, the duty ratio of the pulses is calculated. Along with the randomization of the PWM pulses, we can obtain the effects of spread spectra of voltage, current as in the case of randomly changed switching frequency. To verify the validity of the proposed LL-RPWM, the simulation and experimental study was tried. Along with the randomization PWM pulses, the space vector modulation is also executed in the C167 micro-controller. The simulation and experimental results show that the voltage and current harmonics are spread to a wide band area and that the audible acoustic noise is reduced by the proposed RPWM method.

• The Journal of Korean Medicine
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• v.30 no.5
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• pp.115-126
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• 2009

Objective: By assessing the quality of methodology and synthesis of results of RCTs (Randomized Controlled Clinical Trials) with herbal acupuncture (pharmacopuncture), we hope to help with administrating herbal acupuncture therapy in clinic and conducting RCT with herbal acupuncture. Methods: Reports of RCT conducted in Korea published in medical journals until February 2009 were collected. We surveyed elementary information of RCTs, evaluated randomization, double-blinding, allocation concealment and put together the results of RCTs by seven clinical topics. Results: 38 RCTs with herbal acupuncture were selected, then adequate methods for randomization and allocation concealment were found in 39% and 5% of studies. Complete double-blinding and a clear accounting of all participants were conducted in 42% and 50% of reports. The synthesis of RCTs revealed that herbal acupuncture was useful and effective on degenerative gonarthritis, omarthralgia on cerebrovascular accident, acute ankle sprain, back sprain, neck sprain, headache, rheumatoid arthritis and tennis elbow, generally. Conclusions: Although further improvement in quality of methodology of RCTs with herbal acupuncture is required, clinical usefulness of herbal acupuncture was shown especially on disorders of musculoskeletal system via RCTs.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.106-111
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• 2002

In this paper, a new three phase RPWM(Random PWM)with fixed switching frequency is proposed. In the proposed RPWM, each of three phase pulses is located randomly in each switching interval. Based on the space vector modulation technique, the duty ratio of the pulses is calculated. Along with the the randomization of the PWM pulses, we can obtain the effects of spread spectra of voltage, current as in the case of randomly changed switching frequency. To verify the validity of the proposed RPWM, the experimental study was tried. Along with the randomization of PWM pulses, the space vector modulation is also executed in the C167 micro-controller. The experimental results show that the voltage and current harmonics are spread to a wide band area and that the audible acoustic noise is reduced by the proposed RPWM method.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.12-32
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• 2010

Objective: This study aimed to review herbal remedy-based RCTs on cancer patients in order to produce helpful information for clinical study of herbal medicine in the future. Methods: We collected all RCTs using herbal remedies on cancer patients from Pubmed and Cochrane databases until November 1st, 2009. Elementary information such as nation where performed, clinical question, design, randomization, double-blinding and allocation concealment were analyzed. Results: 153 RCTs were finally selected. 119 RCTs were conduced in China while only 2 were done in Korea. The most frequent targeted cancer was lung cancer as 29 RCTs. The main clinical questions included improvement of quality of life, elongation of survival rate and regression of tumor being 83, 62 and 55 respectively. 112 RCTs used herbal remedies with western therapy. Adequate methods for randomization and allocation concealment were found in 37% and 10% of trials respectively. Conclusions: We found that herbal remedies are used on cancer patients in aspects of both caring for the human body and tumor treatment itself. The study might provide us useful data for cancer-related clinical study using herbal remedies in the future.

• Communications for Statistical Applications and Methods
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• v.28 no.5
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• pp.411-424
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• 2021

Inference following two-stage adaptive designs (also known as two-stage randomization designs) with survival endpoints usually focuses on estimating and comparing survival distributions for the different treatment strategies. The aim is to identify the treatment strategy(ies) that leads to better survival of the patients. The objectives of this study were to assess the performance three commonly cited methods for estimating survival distributions in two-stage randomization designs. We review three non-parametric methods for estimating survival distributions in two-stage adaptive designs and compare their performance using simulation studies. The simulation studies show that the method based on the marginal mean model is badly affected by high censoring rates and response rate. The other two methods which are natural extensions of the Nelson-Aalen estimator and the Kaplan-Meier estimator have similar performance. These two methods yield survival estimates which have less bias and more precise than the marginal mean model even in cases of small sample sizes. The weighted versions of the Nelson-Aalen and the Kaplan-Meier estimators are less affected by high censoring rates and low response rates. The bias of the method based on the marginal mean model increases rapidly with increase in censoring rate compared to the other two methods. We apply the three methods to a leukemia clinical trial dataset and also compare the results.

• Journal of Acupuncture Research
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• v.29 no.5
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• pp.109-118
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• 2012

Objectives : The aim of this study was to evaluate the effectiveness and safety of acupuncture for chronic fatigue syndrome and idiopathic chronic fatigue. Methods : A randomized, controlled pilot trial was conducted. Twenty-four participants were randomized into one of the two groups: an acupuncture group(n=12) and wait-list group(n=12). The treatment group received 12 sessions of acupuncture over 4 weeks. Eight points($GV_{20}$; bilateral GB20, $BL_{11}$, $BL_{13}$, $BL_{15}$, $BL_{18}$, $BL_{20}$, and $BL_{23}$) were selected for needling. The control group did not receive acupuncture treatment during study period and follow-up were done in the $5^{th}$ and $9^{th}$ weeks after randomization in both groups. The primary outcome was fatigue severity scale(FSS) and the secondary outcomes included a short form of stress response inventory(SRI-short form), beck depression inventory(BDI), and insomnia severity index(ISI). Safety was assessed at every visit. Results : There were statistically significant differences in the between group values of FSS at $5^{th}$ weeks after randomization(p=0.0002), SRI-short form, BDI, and ISI at $5^{th}$, $9^{th}$ weeks after randomization(p<0.01). There were no adverse events. Conclusions : The results suggest that acupuncture is associated with benefits on the short-term outcomes in chronic fatigue syndrome and idiopathic chronic fatigue.

• The Mathematical Education
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• v.38 no.2
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• pp.165-172
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• 1999

$\sub$e/$\^$2/, that were results from those three sources of such imperfection. Especially to eliminate the differences in severity among many raters the randomization procedure of raters sample was very effective in enhancing the reliability of ratings with comparatively small groups of examinees and raters. And we also introduced the new rating methods, i.e. the 2-step diagnostic procedures to check the sizes of the reliability stability of raters and the sore adjustment method to enumerate the optimal mean values in rating the examinees.