• Communications for Statistical Applications and Methods
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• v.18 no.2
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• pp.179-187
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• 2011

The purpose of a Phase I clinical trial is to estimate the maximum tolerated dose, MTD, of a new drug. In this paper, the MTD estimation method is suggested by curve fitting the dose-toxicity data to an S-shaped curve. The suggested MTD estimation method is compared with established MTD estimation procedures using a Monte Carlo simulation study.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.543-564
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• 1999

The principal aim of a sequential phase I clinical trial in which the toxicity reponses of a group of patient(s) determine the dose level of the next patient(s) group is to estimate the maximal tolerated dose(MTD) of a new drug, In this paper we compared with a simulation study the performance of the MTD estimates that are determined by a stopping rule in a design and also those that are determined by analyzing the data after a clinical trial is terminated. To the latter belong the mean median mode and maximum likelihood estimates. For the Standard Methods the stopping rule MTD is quite inefficient but the median MTD has a best efficiency and is robust with respect to the three different toxicity curves. The problem of non-convergence of MLE MTD is severe. A more improved MTD estimate is produced by combining the advantages of the various MTD estimates and its efficiency is better than the single median MTD estimate especially for the toxicity curve of an unlucky choice of dose levels. The simulation results suggest that simple types of phase I designs can be combined with relatively standard analytic techniques to provide a more efficient MTD estimate.

• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.741-752
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• 2019

The purpose of a Phase I Clinical Trial is to determine the maximum tolerated dose (MTD). MTD is important because it affects subsequent clinical trials; however, the existing method has a problem due to an inadequate dose allocated to patients. In this paper, an MTD estimation method is proposed to complement the problems of the existing MTD estimation method. The suggested method applies the initial acceleration step to the modified continual reassessment method. Monte Carlo Simulation Study is adapted to compare a suggested MTD estimation method with the standard design and the modified continual reassessment method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.1063-1075
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• 2022

In recent years, container techniques have been broadly applied to cloud computing systems to maximize their efficiency, flexibility, and economic feasibility. Concurrently, studies have also been conducted to ensure the security of cloud computing. Among these studies, moving-target defense techniques using the high agility and flexibility of cloud-computing systems are gaining attention. Moving-target defense (MTD) is a technique that prevents various security threats in advance by proactively changing the main attributes of the protected target to confuse the attacker. However, an analysis of existing MTD techniques revealed that, although they are capable of deceiving attackers, MTD techniques have practical limitations when applied to an actual cloud-computing system. These limitations include resource wastage, management complexity caused by additional function implementation and system introduction, and a potential increase in attack complexity. Accordingly, this paper proposes a software-defined MTD system that can flexibly apply and manage existing and future MTD techniques. The proposed software-defined MTD system is designed to correctly define a valid mutation range and cycle for each moving-target technique and monitor system-resource status in a software-defined manner. Consequently, the proposed method can flexibly reflect the requirements of each MTD technique without any additional hardware by using a software-defined approach. Moreover, the increased attack complexity can be resolved by applying multiple MTD techniques.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.747-756
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• 1999

Background: Acid-fast stain and cultures for diagnosis of pulmonary tuberculosis are primary and essential method, but have their limitation : low sensitivity and time consuming. The objective of this study is comparison of amplified Mycobacterium tuberculosis direct test(MTD) by the conventional AFB smears and cultures in the detection of Mycobacterium tuberculosis in respiratory specimens. Methods: During the period between November, 1997 and May, 1998 a total of 267 respiratory specimens (sputum 173, bronchial washing 94) from 187 patients suspected pulmonary tuberculosis were subjected to AFB smears, cultures and MID test. MID is based on nucleic acid amplification. We compared the MID with 3% Ogawa culture method. In positive AFB smear and negative MID specimen, positive culture identification between nontuberculous mycobacterium and M.tuberculosis was assesed by using Accuprobe M.tuberculosis complex probe. In negative AFB smear and negative AFB culture, MTD results are assessed by clinical follow-up. Results : 1) Compared with culture in sputum and bronchial fluid specimens, sensitivity and specificity of MTD in positive AFB smear is 79.7% and 20.0%, sensitivity and specificity of MTD in negative AFB smear specimens is 75.0% and 79.7%. 2) Discrepant analysis is assessed by clinical follow-up and other specimen results beyond study. Culture negative but MTD positive specimens were proved to be true positive and gave MTD sensitivity 79.2%, specificity of 84.4%, positive predictive value 80.5% and negative predictive value 83.2%. 3) 14 out of 31 specimens in negative AFB smear, negative AFB culture and positive MTD showed pulmonary tuberculosis diagnosed on clinical follow-up and sensitivity is 45.2%. 4) 2 out of 13 specimens in positive AFB smear, positive AFB culture and negative MID diagnosed as non tuberculous mycobacterium by Accuprobe culture. Conclusion: This study suggested that MID in respiratory specimens is simple and rapid diagnostic method, but considered adjuvant method rather than replace the conventional AFB smear and culture.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.57-64
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• 2012

Phase I clinical trials determine the maximum tolerated dose(MTD) of a new drug. In this paper, we proposed a two-stage MTD estimation method by a Stopping rule in a phase I clinical trial. The suggested MTD estimation method is compared to the standard design(SM3) and the continual reassessment method(CRM) using a Monte Carlo simulation study.

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1115-1123
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• 2014

The main purpose of phase I clinical trials is to estimate the Maximum Tolerated Dose (MTD), which minimizes side effect and assures safety of a new drug by evaluating the toxicity at each dose-level. The conventional MTD estimation methods is Standard method (Storer, 1989; Korn et al., 1994), Accelerated Titration Designs (Simon et al., 1997) and DM method (Dixon and Mood, 1948) etc. In this paper, MTD estimation method with de-escalation is suggested phase I clinical trials. The proposed MTD estimation method is compared to Accelerated Titration Designs, SM3 without de-escalation method and SM3 with de-escalation method using a Monte Carlo simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.158-161
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• 2018

2011년 미국에서 최초로 소개된 후 기존 보안 기술과 다른 새로운 정보시스템 보호 기술로 Moving Target Defense(MTD)가 활발히 연구 되고 있다. MTD는 시스템의 구성 요소들을 뷸규칙적이고 동적으로 변화시켜 공격표면(Attack surface)을 줄임으로써 외부 공격에 대한 보안성을 높인다. 주로 시스템 정보를 수집 및 분석하여 공격하는 보안 위협들에 효과적이며 특히 지능형 지속 보안 위협(Advanced Persistent Threat), 킬 체인(Kill-Chain) 보안에 뛰어난 성능을 기대할 수 있다. 최근 MTD 시스템 구현 및 개발로 상용화가 시작되었으나 MTD 활용을 통해 어느 정도의 보안성 및 효율성을 가지는지에 대한 성능 평가인증, 시험지침 등이 표준화 되어있지 않아 기준이 모호한 실정이다. 본 논문에서는 이러한 최근 MTD 이슈에 대해 살펴보고 MTD와 연관 되어있는 각 분야에 어떤 평가인증 요구사항들이 있는지 분석한다. 이를 통해 MTD에 어떠한 평가인증 요구사항이 있는지 도출하여 앞으로 MTD 평가인증 표준화 참고 및 활용에 기여 할 수 있을 것으로 전망한다.

• Phonetics and Speech Sciences
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• v.12 no.4
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• pp.91-98
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• 2020

This study investigated the acoustic characteristics of sustained vowel /a/ and sentence utterance produced by patients with muscle tension dysphonia (MTD) using cepstrum-based acoustic variables. 36 women diagnosed with MTD and the same number of women with normal voice participated in the study and the data were recorded and measured by ADSVTM. The results demonstrated that cepstral peak prominence (CPP) and CPP_F0 among all of the variables were statistically significantly lower than those of control group. When it comes to the GRBAS scale, overall severity (G) was most prominent, and roughness (R), breathiness (B), and strain (S) indices followed in order in the voice quality of MTD patients. As these characteristics increased, a statistically significant negative correlation was observed in CPP. We tried to classify MTD and control group using CPP and CPP_F0 variables. As a result of statistic modeling with a Random Forest machine learning algorithm, much higher classification accuracy (100% in training data and 83.3% in test data) was found in the sentence reading task, with CPP being proved to be playing a more crucial role in both vowel and sentence reading tasks.

• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.875-881
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• 2021

The mitochondrial targeting domain (MTD) of Noxa contributes to its mitochondrial localization and to apoptosis induction. As a peptide, MTD fused with octa-arginine (R8), a CPP, induces necrosis related to intracellular calcium influx and destruction of mitochondria and endoplasmic reticulum. We searched for homologs of MTD, and compared their cell killing capability when fused with R8. Three of the seven peptides triggered cell death with similar mechanisms. The comparative analysis of peptide sequences showed that four amino acid sites of MTD are critical in regulating necrosis, suggesting the potential to generate artificial, adjustable cytotoxic peptides, which could be effective medicines for many diseases. Thus, homologs functionality could hint to the functions of their belonging proteins.