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.

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.

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.

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.

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.

An Approach to One-Year Time Series Anal ysis of Physical Growth in Young Children

Fujii, Katsunori(후지이 카츠노리),Kasuya, Kohsuke(카스야 코스케),Kim, Jun-Dong(김준동) 한국체육과학회 2016 한국체육과학회지 Vol.25 No.6

유아기 신체발육의 대하여, 월별로 해석되는 발달은 계절변동인지 주기적 변동인지 찬반의견이 갈리지만, 결국 주기적변동의 요소가 강하다는 의견이 있다. 따라서 본 연구는 유아기 어린나이의 유아를 대상으로 신장을 월별로 측정하여 Wavelet 보정법으로 해석하였다. 발육속도곡선을 나타나고 LPV(Local Peak Velocity) 출현점을 해석하였다. 이러한 신장 월별발육 패턴의 주기성은 어린 남유아 54명, 여유아 58명의 1년간 신장 데이터에서 얻었으며, Wavelet 보정법을 사용하고 월별 발육현량치 곡선을 미분하여 속도곡선 LPV를 얻었다. 검출된 1년간 LPV 출현 패턴은 남녀유아 모두 3군데, 4군데인 경우가 많았다. LPV 출현시기는 남녀유아 모두 5-6월경, 8-9월경, 12월경에 나타났다. 최대 LPV 출현시기는 5-6월경과 8-9월경에 다수 나타났다. 따라서 신장의 주기적 변동으로서 여름에 발육이 촉진되지만, 한편으로는 겨울이라도 발육이 촉진되는 경우도 있어, 역시 유전적인 신장 월별발육 패턴에는 주기성이 추정된다. 유아 중에서 약간 나이가 높은 유아의 경우도 비슷한 경향이 나타나고 있고, 결국, 계절변동 보다는 유전적인 주기적 발육 패턴이 보인다고 할 수 있다.

Postbuckling strength of an axially compressed elastic circular cylinder with all symmetry broken

Fujii, Fumio,Noguchi, Hirohisa Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.11 No.2

Axially compressed circular cylinders repeat symmetry-breaking bifurcation in the postbuckling region. There exist stable equilibria with all symmetry broken in the buckled configuration, and the minimum postbuckling strength is attained at the deep bottom of closely spaced equilibrium branches. The load level corresponding to such postbuckling stable solutions is usually much lower than the initial buckling load and may serve as a strength limit in shell stability design. The primary concern in the present paper is to compute these possible postbuckling stable solutions at the deep bottom of the postbuckling region. Two computational approaches are used for this purpose. One is the application of individual procedures in computational bifurcation theory. Path-tracing, pinpointing bifurcation points and (local) branch-switching are all applied to follow carefully the postbuckling branches with the decreasing load in order to attain the target at the bottom of the postbuckling region. The buckled shell configuration loses its symmetry stepwise after each (local) branch-switching procedure. The other is to introduce the idea of path jumping (namely, generalized global branch-switching) with static imperfection. The static response of the cylinder under two-parameter loading is computed to enable a direct access to postbuckling equilibria from the prebuckling state. In the numerical example of an elastic perfect circular cylinder, stable postbuckling solutions are computed in these two approaches. It is demonstrated that a direct path jump from the undeformed state to postbuckling stable equilibria is possible for an appropriate choice of static perturbations.