여자스포츠선수의 신체적 스트레스성 초경지연에 대한 검증

藤井勝紀(Katsunori Fujii),김준동(Jun Dong Kim),노호성(Hosung Nho) 한국발육발달학회 2011 한국발육발달학회지 Vol.19 No.1

In this study, to determine delayed menarche in individual female athletes, the age at maximum peak velocity of height and the age at menarche of female athletes were applied to the delayed menarche evaluation system developed by Fujii. The age at maximum peak velocity of BMI and the interval with age at menarche were then analyzed for girls judged to have had delayed menarche. An attempt was made to verify the frequency with which physical stress gives rise to delayed menarche. The subjects were 144 female athletes in their final year of high school who had participated in national sports tournaments during their high school years. A control group was made up of 78 girls who did not regularly participate in sports. Information including age, age at menarche, and athletic practice was obtained from a questionnaire given to the athletes and control group. Data were also obtained on the girls longitudinal growth in height and weight from the first year of elementary school (6 years old) to the final year of high school. BMI was calculated from this data, and the wavelet interpolation method was applied for changes in height and BMI with age from 6 to 17 years old. It was found that among female athletes judged to have had delayed menarche the physical stress type of delayed menarche was much more common than fat-related delayed menarche. Therefore, it is speculated that physical stress acts a large role in delayed menarche in athletes.

일본여성의 지역적 차이에 의한 초경지연의 발육학적 검증

藤井勝紀(Katsunori FUJII),노호성(Noh Ho-sung) 한국체육과학회 2009 한국체육과학회지 Vol.18 No.2

To elucidate delayed menarche in female athletes, Fujii established a system to evaluate delayed menarche by deriving the delay in menarche from the interval between age at MPV of height and age at menarche, while at the same time establishing judgments from regression evaluations of age at menarche against age at MPV of height. In this study, the system Fujii developed to evaluate delays in menarche was applied to the age at menarche of girls in the Tokai and Hokuriki regions of Japan, and we then investigated regional differences in delays in menarche between these two regions. The girls were 209 girls from the Tokai region and 96 girls from the Hokuriku region who underwent almost no sports training around the time of menarche. Longitudinal growth data on the girls’ height were obtained from health records from the first year of elementary school until the final (third) year of high school. The age at menarche was obtained from a questionnaire survey of the 209 girls in the Tokai region and 96 girls in the Hokuriku region. The delayed menarche evaluation system was applied to the age at menarche of girls from the Tokai and Hokuriku regions, and the average delay in menarche in the Hokuriku region was estimated from the interval between age at MPV of height and age at menarche. Regression evaluation of age at menarche against age at MPV of height was used to clarify the delay in menarche for individual girls in the Hokuriku region. It was shown that the proportion of girls with delayed menarche was significantly higher in the Hokuriku region than in the Tokai region. This was inferred to be from the effect of stress from living conditions that results from the characteristic climate of the Hokuriku region.

Riccati Equation and Positivity of Operator Matrices

Fujii, Jun Ichi,Fujii, Masatoshi,Nakamoto, Ritsuo Department of Mathematics 2009 Kyungpook mathematical journal Vol.49 No.4

We show that for an algebraic Riccati equation $X^*B^{-1}X-T^*X-X^*T=C$, its solutions are given by X = W + BT for some solution W of $X^*B^{-1}X$ = $C+T^*BT$. To generalize this, we give an equivalent condition for $\(\array{B&W\\W*&A}\)\;{\geq}\;0$ for given positive operators B and A, by which it can be regarded as Riccati inequality $X^*B^{-1}X{\leq}A$. As an application, the harmonic mean B ! C is explicitly written even if B and C are noninvertible.

Daily activity relates to not only femoral bone mineral density, but also hip structural analysis parameters: A cross-sectional observational study

Norifumi Fujii,Nobukazu Okimoto,Manabu Tsukamoto,Norimitsu Fujii,Kei Asano,Yoshiaki Ikejiri,Toru Yoshioka,Takafumi Tajima,Yoshiaki Yamanaka,Yukichi Zenke,Makoto Kawasaki,Junya Ozawa,Takuya Umehara,Sho 대한골다공증학회 2021 Osteoporosis and Sarcopenia Vol.7 No.4

Objectives: Physical activity to maintain bone mass and strength is important for hip fracture prevention. We aim to investigate the relationship between physical performance/activity status and bone mineral density (BMD)/hip structural analysis (HSA) parameters among postmenopausal women in Japan. Methods: Sixty-two postmenopausal women diagnosed with osteoporosis (mean age: 72.61 ± 7.43 years) were enrolled in this cross-sectional observational study. They were evaluated for BMD and HSA in the proximal femur by dual-energy X-ray absorptiometry and underwent several physical performance tests, the Geriatric Locomotive Function Scale of 25 questions (GLFS-25). Principal component analysis (PCA) was used to summarize data on the BMD/HSA parameters. Partial correlation analysis, multiple regression analysis, and structural equation modeling (SEM) were performed to investigate the relationship between physical performance/activity status and BMD/HSA parameters of the proximal femur. Results: In a partial correlation analysis adjusted for age and body mass index (BMI), GLFS-25 scores were correlated with HSA parameter (|r| = 0.260-0.396, P < 0.05). Principal component 1 (PC1) calculated by PCA was interpreted as more reflective of bone strength based on the value of BMD/HSA parameters. The SEM results showed that the model created by the 3 questions (Q13, brisk walking; Q15, keep walking without rest; Q20, load-bearing tasks and housework) of the GLFS-25 had the best fit and was associated with the PC1 score (β = -0.444, P = 0.001). Conclusions: The GLFS-25 score was associated with the BMD/HSA parameter, which may reflect the bone strength of the proximal femur as calculated by PCA.

쌍생아 여아의 유사성 평가 차트의 확립

藤井勝紀(Fujii, Katsunori),김준동(Kim, Jun-Dong) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.4

Twin studies have important implications for verifying the involvement of various genetic and environmental factors in human characteristics. Among these twin studies, many statistical analyses of the similarities of monozygotic and dizygotic twins require twin pair data. To analyze the similarities of growth process in pair data for twin pairs, Fujii described the growth curve with the wavelet interpolation model and proposed a method of analyzing the similarities between the described growth curves based on cross-correlation functions. In this study, an assessment criteria chart was constructed to evaluate the similarities between girls’ monozygotic and dizygotic twins by applying wavelet interpolation model to these growth curve descriptions and cross-correlation functions. Height growth data for random pairs of general girls were taken and the growth processes were described with the wavelet interpolation method. Cross-correlation functions were then applied to the growth velocity curves of the described random pairs. An evaluation chart of similarities was built from the derived cross-correlation functions, and in the cross-correlation functions from those evaluation charts, r ≧ 0.94 was found to be the standard criterion showing the level of similarity. When the cross-correlation functions of height growth of monozygotic and dizygotic twins were applied to these charts, the correlation of monozygotic twins was high and that of dizygotic twins was somewhat high. Thus, the similarity of monozygotic twins was seen to be high.

Wavelet Interpolation 방법에 의한 한국청소년의 신장발육 경향변화에 관한 검증

등정승기(Katsunori Fujii),김설향(Seol Hyang Kim),노호성(Ho Sung Nho) 한국발육발달학회 2008 한국발육발달학회지 Vol.16 No.4

The height cross-sectional growth data of children 7 years-old (first year of primary school) to 18 years-old (third year of high school) are analyzed using the results of a survey examining annual height growth, which is published every three years since 1989 in a National Survey of Physical Strength conducted by the South Korean Sports Science Research Institute. Although the annual change in physical strength and physique are officially announced in South Korea, no report examining these annual changes has yet been published. The predominate analytic method used to date has been the growth distance curve, while velocity curve analysis is used to analyze the differential value of annual growth; although large-scale, these cannot be guaranteed to be objective methods of corroborating early physical maturation. At this juncture, the wavelet interpolation method advocated by Fujii (2006) can be applied, first, to specify the age at maximum peak velocity (MPV) during adolescence from the description of the height growth velocity curve, and verify the early physical maturation of South Korean youth from the annual change in the age MPV of height. In verifying the height growth of South Korean youth using the wavelet interpolation method in the present study, the early maturation and change in growth pattern indicated by the younger age of MPV is thought to be objective evidence of the influence of the high degree of socioeconomic growth on morphological development in South Korea. However, the era of high economic growth in South Korea is already be ending, and with it the current period of enhanced growth may be ending also. Therefore, the annual change of increasing height among male and female youths is unlikely to resultina slow do wnin grow thsimilar to the Japanese.

동 아시아민족 발육에 관한 年次推移의 검증

藤井勝紀(Katsunori Fujii),김준동(Kim Jun-dong),노호성(Nho Ho-Sung) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.1

This study attempted to be made to demonstrate the changes in morphological growth in two recent periods of the East Asia ethnic groups, by comparing the morphological growth in adolescence of Japanese, Korean, Han Chinese and Mongols groups in the years 1985 and 1989, and 2004 and 2005. This study applied the wavelet interpolation method proposed by Fujii, and specified the age of maximum peak velocity (MPV) in growth during puberty from the height and weight growth velocity curve. Then, based on age at MPV and annual changes in MPV, early maturation in height growth and time changes in the velocity curve in the East Asia ethnic groups was demonstrated. The results did not reveal any marked changes in the growth of Japanese and Korean boys and girls between these two periods. However, a tendency for earlier age at MPV was seen in both boys and girls in Han and Mongol Chinese. This tendency was particularly marked in Mongols, and maturity was clearly earlier. The trend in these recent 20 years from 1985 to 2005 in Inner Mongolia is thought to be similar to the past phenomenon of earlier maturation in Japanese that was clearly earlier. The trend in these recent 20 years from 1985 to 2005 in Inner Mongolia is thought to be similar to the past phenomenon of earlier maturation in Japanese that was influenced by high socioeconomic development. The factors for the change seen in Mongols are assumed to be considerable improvements in recent years in the dietary habits and environment of Mongols in the Inner Mongolia Autonomous Region of China, and improvements in their social and economic environment.

여성의 신장이 초경지연에 미치는 위험요인 분석

藤井勝紀 ( Katsunori Fujii ),김준동 ( Kim Jun-dong ) 한국유산소운동과학학회 2018 한국유산소운동과학회지 Vol.16 No.1

The assumption in delayed menarche was that menarche is delayed in females who train regularly before and after onset due to excessive physical and mental stress. However, methodological problems involved with producing a precise explanation for delayed menarche have not yet been solved. Even when menarche is indeed delayed, the influence of sports training cannot be confirmed. Fujii verified delayed menarche in female athletes by examining the interval between age at the maximum peak velocity of height (MPV), a measure of maximum growth velocity during adolescence and age at menarche derived from the wavelet interpolation method (WIM). Based on the above finding, level of body stature was also classified from height in this study, with the second year of high school as the reference, against the constructed evaluation chart. Girls were classified by height as tall, average, or short, and an attempt was made to evaluate delayed menarche by height classification. Thus, risk analysis of delayed menarche in Koreans girls was done by applying the delayed menarche evaluation system for tall-short type.

An overview of developments and applications of oceanographic radar networks in Asia and Oceania countries

Fujii, S.,Heron, M. L.,Kim, K.,Lai, J. W.,Lee, S. H.,Wu, X.,Wu, X.,Wyatt, L. R.,Yang, W. C. Korean Ocean Research Development Institute and Ko 2013 OCEAN SCIENCE JOURNAL Vol.48 No.1

자연과학편 : 유아의 체격,운동능력을 중심으로 연령증가변화를 파악하기 위한 평가차트의 구축

( Fujii Katsunori ),( Tanaka Nozomi ),김준동(JunDongKim) 한국체육학회 2014 한국체육학회지 Vol.53 No.6

본 연구는 3세에서 5세까지의 일본유아(남아: 318명, 여아: 332명)를 대상으로 체격과 운동능력결과에 최소이승근이다항식을 적용하고 연령증가에 따른 영향을 검토하였다. 측정항목은 신장, 체중, 체지방량, 근육률, 20 m달리기, 제자리멀리뛰기, 테니스공던지기, 줄 넘고 기어 나오기이었으며, 측정결과에 따라 연령증가경향이 나타난 신체적 요소에대하여 월 연령을 계산한 회귀다항식평가차트를 구축하였다. 측정결과는 3세부터 5세까지 신장·체중이 직선적 연령증가가 나타났지만, 체지방률, 근육률의 연령증가변화는 나타나지 않았다. 운동능력에서는 4종목 모두 명확한 연령증가변화가 나타났다. 월 연령을 고려하면, 신장, 체중, 20 m달리기, 제자리멀리뛰기, 테니스공던지기, 줄 넘고 기어 나오기에서 연령증가변화가 나타남으로써 1차부터 3차까지 회기다항식평가차트의 구축이 가능하게 되었다. 이러한 분석방법은 서로 다른 연령의 유아를 대상으로, 운동능력을 동시에 비교·평가할 수 있다는 장점이 있다고 사료된다. In this study we applied least squares approximation to exact monthly age over a three-year span for physique, bodycomposition and motor fitness in 3- and 5-year-old Japanese children, and examined the age composition. The subjects werepreschool children in some kindergartens of Aichi prefecture. They included 318 boys and 332 girls enrolled in the study inMay 2009. The physical attributes measured were height, weight for physique, and body fat, muscle percentage for bodycomposition, and 20 m dash, standing long jump, tennis ball throw, and jump over-and-under for motor fitness. A leastsquares approximation polynomial was applied to the measured values for physique and motor fitness at exact month of age. A change with age was seen in height and weight for both boys and girls, and from a primary to cubic regression polynomialwas valid. However, no change with age in body fat and muscle percentage were seen. Changes with age in physical fitnessitems were seen in both boys and girls for 20 m dash, standing long jump, tennis ball throw and jump over-and-under. Inphysique, cubic regression polynomials were valid for height in boys, and primary regression polynomials were valid forweight in boys and height and weight in girls. All of these are items for which from a primary regression to cubic polynomialwere valid. An attempt was made to construct a regression evaluation chart for month of age with consideration of this agecomposition.