• Title/Summary/Keyword: CLT

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An Empirical Central Limit Theorem for the Kaplan-Meier Integral Process on [0,$\infty$)

  • Bae, Jong-Sig
    • Journal of the Korean Statistical Society
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    • v.26 no.2
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    • pp.231-243
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    • 1997
  • In this paper we investigate weak convergence of the intergral processes whose index set is the non-compact infinite time interval. Our first goal is to develop the empirical central limit theorem as random elements of [0, .infty.) for an integral process which is constructed from iid variables. In developing the weak convergence as random elements of D[0, .infty.), we will use a result of Ossiander(4) whose proof heavily depends on the total boundedness of the index set. Our next goal is to establish the empirical central limit theorem for the Kaplan-Meier integral process as random elements of D[0, .infty.). In achieving the the goal, we will use the above iid result, a representation of State(6) on the Kaplan-Meier integral, and a lemma on the uniform order of convergence. The first result, in some sense, generalizes the result of empirical central limit therem of Pollard(5) where the process is regarded as random elements of D[-.infty., .infty.] and the sample paths of limiting Gaussian process may jump. The second result generalizes the first result to random censorship model. The later also generalizes one dimensional central limit theorem of Stute(6) to a process version. These results may be used in the nonparametric statistical inference.

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The Effects of a Coordinative Locomotor Training Program on the Functional Movement Screen Scores of Badminton Players (CLT 프로그램이 배드민턴 선수의 Functional Movement Screen 점수에 미치는 효과)

  • Kim, Tae-Yoon;Kim, Seok-Hwan
    • PNF and Movement
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    • v.14 no.1
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    • pp.23-32
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    • 2016
  • Purpose: The purpose of this study was to determine the effects of a coordinative locomotor training program on the functional movement screen (FMS) scores of badminton players. Methods: The participants consisted of 31 badminton players who were randomly assigned to either an experimental group (n=15) or a control group (n=16), and engaged in exercise five times per week for six weeks. The experimental group engaged in coordinative locomotor training and the control group engaged in general exercise. An FMS kit (USA) was used to measure the following: FMS score, deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push up, and rotary stability. Results: The FMS score, deep squat, hurdle step, in-line lunge, active straight leg raise, and trunk stability push up showed significant improvement in the experimental group (p<0.05). Conclusion: The coordinative locomotor training program was able to produce confirmation that functional movement screen scores change in the case of effective exercise interventions in badminton players.

On Improving the Listening Ability of Middle School Students Using Verbotonal Method (Verbotonal 법을 이용한 중학생 영어 학습자의 듣기 능력 향상에 관한 연구)

  • Kim, Hyun-Gi;Kim, Ok-Jin;Kang, Sung-Kwan;Jeon, Byoung-Man
    • Speech Sciences
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    • v.14 no.3
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    • pp.21-29
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    • 2007
  • The necessity for improving the English listening ability of Korean learners has been emphasized since the ultimate goal of English education converted to CLT(Communicative Language Teaching) in Korea. Verbotonal Approach as an auditory-based strategy has been proved to be effective substantially in maximizing the listening skill of spoken foreign language. The purpose of this study is to find out an efficient way of improving listening ability for Korean middle school students by employing OFH(Optimal Frequency of Hearing) using Tonality Word Sentence Test, before & after using Listen II Verbotonal training unit based on VTS(Verbotonal System). The results of the listening tests showed that the listening ability of the subjects increased by 16.7% on the words and by 5.5% on the sentences after using Listen II, compared with before using Listen II and that the improvement rate of listening ability on the level of words is much higher than that on the level of sentences. From the results, we can come to a conclusion that training the listening skill with words in mid-tonality and low-tonality based on OFH might give a great positive effect in improving listening ability for Korean learners of English.

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A New Statistical Approach for the Estimation of Range and Degree of Fisheries Damages Caused by Public Undertaking (공공사업으로 인한 어업피해 범위와 피해정도 추정의 새로운 통계학적 접근)

  • 강용주;김기수;장창익;박청길;이종섭
    • The Journal of Fisheries Business Administration
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    • v.35 no.1
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    • pp.117-132
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    • 2004
  • This study attempts to suggest a new approach of the estimation of range and degree of fisheries damages caused by a large scale of reclamation undertaken in coastal area using the central limit theorem(CLT) in statistics. The key result of the study is the introduction of the new concept of critical variation of environmental factor($d_{c}$). The study defines $d_{c}$ as a standard deviation of the sample mean($\bar{X}$) of environmental factor(X), in other words, $\frac{\sigma}{ \sqrt{n}}$. The inner bound of $d_{c}$ could be the area of fisheries damages caused by public coastal undertaking. The study also defines the decreasing rate of fisheries production$\delta_{\varepsilon}$, in other words, degree of fisheries damages, as the rate of change in the distribution of sample mean(($\bar{X}$), caused by the continuous and constant variation of environmental factor. Therefore $\delta_{\varepsilon}$ can be easily calculated by the use of table of the standardized normal distribution.

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Drug Interaction between Flavone and Paclitaxel in Rats (프라본과 파크리탁셀과의 약물상호작용)

  • 최준식;이진환
    • YAKHAK HOEJI
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    • v.47 no.2
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    • pp.98-103
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    • 2003
  • The purpose of this study was to investigate the effect of flavone (20 mg/kg) on the pharmacokinetic parameters and the bioavailability of paclitaxel (40 mg/kg) orally coadministered in rats. The plasma concentration of paclitaxel in combination with flavone was increased significantly (coadministration p<0.05, pretreatment p<0.0l) compared to that of control. Area under the plasma concentration-time curve (AVC) of paclitaxel with flavone was significantly (coadministration p<0.05, pretreatment p<0.0l) higher than that of control. Peak concentration (Cmax) of paclitaxel with flavone were significantly increased (coadministration p<0.05, pretreatment p<0.01) compared to that of control. Time to peak concentration (Tmax) of paclitaxel with flavone decreased significantly (p<0.05) than that of control. The total body clearance (CLt) and elimination rate constant ($\beta$) of paclitaxel with flavone were significantly reduced (p<0.05) compared to those of control. Half-life (t$_{1}$2/) of paclitaxel with flavone was significantly prolonged (p<0.05) compared to that of control. Based on these results, it might be concluded that flavone may enhance bioavailability of paclitaxel through the inhibition of cytochrome P450 and P-glycoprotein, which are engaged in paclitaxel absorption and metabolism in liver and gastrogintestinal mucosa, respectively.

Optimized Lamina Size Maximizing Yield for Cross Laminated Timber Using Domestic Trees

  • Jeong, Gi-Young;Lee, Jun-Jae;Yeo, Hwan-Myeong;Hong, Jung-Pyo;Kim, Hyung-Kun;So, Won-Tek;Chung, Woo-Yang
    • Journal of the Korean Wood Science and Technology
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    • v.41 no.2
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    • pp.141-148
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    • 2013
  • The goal of this study was to find the optimum lamina size from red pine (Pinus densiflora) and Japanese cedar (Cryptomeria japonica) logs for the cross laminated timber (CLT) production. From visual inspection of the logs from two species, red pine log showed a larger knot and warp compared to the Japanese cedar. Different cross-sectional sizes of lamina ($110mm{\times}30mm$, $110mm{\times}40mm$, $110mm{\times}50mm$, $50mm{\times}30mm$, $30mm{\times}30mm$) from two species were analyzed for yield and grade. Regardless of the species, the optimized cross sectional size for maximizing the yield was $110mm{\times}30mm$. In grading for the different size laminas from Japanese cedar and red pine, a higher percentage of the first and second grade was found from the $110mm{\times}30mm$ lamina cut.

The Effect of Coordinative Locomotor Training Using Elastic Bands on the Flexibility and Body Alignment of Elementary School Right-Handed Baseball Players

  • Jeong, Mobeom
    • The Journal of Korean Physical Therapy
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    • v.33 no.5
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    • pp.217-223
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    • 2021
  • Purpose: This study sought to identify the effects of coordinative locomotor training (CLT) using elastic bands on the flexibility and body alignment of right-handed baseball players in elementary school. Methods: The subjects were 20 instructed right-handed baseball players in elementary school. They were classified into the experimental group with 10 players (n=10) to be given coordinative locomotor training using elastic bands and the control group with 10 players (n=10). Flexibility was measured by the sit and reach exercise. Body alignment was measured using formetric 4D method to measure the trunk imbalance angle (TI), trunk torsion angle (TT), pelvic tilt angle (PTi), pelvic torsion angle (PTo), pelvic rotation angle (PR), kyphotic angle (Ky), and lordotic angle (Lo). Results: There was a significant increase in the flexibility within the experimental group (p<0.05). after the intervention. There was also a significant increase in the difference between the experimental group and the control group (p<0.05). There was a significant decrease in PR during body alignment in the experimental group after intervention (p<0.05). An analysis of the differences between groups showed a significant decrease in the PR of the experimental group compared to the control group (p<0.05). Conclusion: These findings show that coordinative locomotor training using elastic bands would be effective for enhancing the flexibility and pelvic rotation of elementary school right-handed baseball players.

Interval prediction on the sum of binary random variables indexed by a graph

  • Park, Seongoh;Hahn, Kyu S.;Lim, Johan;Son, Won
    • Communications for Statistical Applications and Methods
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    • v.26 no.3
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    • pp.261-272
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    • 2019
  • In this paper, we propose a procedure to build a prediction interval of the sum of dependent binary random variables over a graph to account for the dependence among binary variables. Our main interest is to find a prediction interval of the weighted sum of dependent binary random variables indexed by a graph. This problem is motivated by the prediction problem of various elections including Korean National Assembly and US presidential election. Traditional and popular approaches to construct the prediction interval of the seats won by major parties are normal approximation by the CLT and Monte Carlo method by generating many independent Bernoulli random variables assuming that those binary random variables are independent and the success probabilities are known constants. However, in practice, the survey results (also the exit polls) on the election are random and hardly independent to each other. They are more often spatially correlated random variables. To take this into account, we suggest a spatial auto-regressive (AR) model for the surveyed success probabilities, and propose a residual based bootstrap procedure to construct the prediction interval of the sum of the binary outcomes. Finally, we apply the procedure to building the prediction intervals of the number of legislative seats won by each party from the exit poll data in the $19^{th}$ and $20^{th}$ Korea National Assembly elections.

Performance of Six-Layered Cross Laminated Timber of Fast-Growing Species Glued with Tannin Resorcinol Formaldehyde

  • Deazy Rachmi TRISATYA;Adi SANTOSO;Abdurrachman ABDURRACHMAN;Dina Alva PRASTIWI
    • Journal of the Korean Wood Science and Technology
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    • v.51 no.2
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    • pp.81-97
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    • 2023
  • The aim of this study were to evaluate tannin resorcinol formaldehyde (TRF) for the preparation of cross-laminated timbers (CLTs) made from fast-growing tree species and to analyze the physical and mechanical properties of CLTs. TRF copolymer resin was prepared by using the bark extracts of Swietenia mahagoni (L.) Jacq. It was observed that the TRF adhesive possessed less solid content (23.59%), high viscosity (11.35 poise), and high pH values (10.0) compared to the standard phenol resorcinol formaldehyde. The TRF adhesive was applied to produce CLTs with the addition of 15% tapioca and flour as an extender. The six-layered CLTs were produced from sengon (Falcataria moluccana Miq.), jabon [Anthocephalus cadamba (Roxb) Miq.], coconut (Cocos nucifera L.), and the combination of coconut-jabon and coconut-sengon wood. The analysis of variance revealed that the layer composition of CLT significantly affected the physical and mechanical properties of the beam. While the modulus of rupture met the standard, the moisture content and modulus of elasticity values did not fulfill JAS 1152-2007. All of the CLTs produced in this study demonstrated low formaldehyde emission, ranging from 0.001 mg/L to 0.003 mg/L, thereby satisfying the JAS 1152 for structural glue laminated timber.

Text Mining of Wood Science Research Published in Korean and Japanese Journals

  • Eun-Suk JANG
    • Journal of the Korean Wood Science and Technology
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    • v.51 no.6
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    • pp.458-469
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    • 2023
  • Text mining techniques provide valuable insights into research information across various fields. In this study, text mining was used to identify research trends in wood science from 2012 to 2022, with a focus on representative journals published in Korea and Japan. Abstracts from Journal of the Korean Wood Science and Technology (JKWST, 785 articles) and Journal of Wood Science (JWS, 812 articles) obtained from the SCOPUS database were analyzed in terms of the word frequency (specifically, term frequency-inverse document frequency) and co-occurrence network analysis. Both journals showed a significant occurrence of words related to the physical and mechanical properties of wood. Furthermore, words related to wood species native to each country and their respective timber industries frequently appeared in both journals. CLT was a common keyword in engineering wood materials in Korea and Japan. In addition, the keywords "MDF," "MUF," and "GFRP" were ranked in the top 50 in Korea. Research on wood anatomy was inferred to be more active in Japan than in Korea. Co-occurrence network analysis showed that words related to the physical and structural characteristics of wood were organically related to wood materials.