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.

Electronic structure of high-quality rubrene single crystal

Jun NITTA,Kazumoto MIWA,Emilia ANNESE,Jun FUJII,Shimpei ONO,Kazuyuki SAKAMOTO 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

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.

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.

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.

한국유아를 대상으로 실시한 비만·마른형정도와 체력의 상관관계에 대한 검증

藤井勝紀(Katsunori Fujii),박태섭(Tae Seop Park),이동준(Dong Jun Lee),김은정(Eun Jung Kim),김준동(Jun Dong Kim) 한국발육발달학회 2011 한국발육발달학회지 Vol.19 No.2

Few reports have investigated the relation between body fatness and physical strength in young Korean children. To provide basic information on growth and development of Korean children, in this study we measured physique and physical strength in 6- and 7-year-old Korean boys and girls, determined body fatness from a polynomial regression evaluation of body weight against height, and investigated physical strength for children of each determined body fatness. To create a regression polynomial of body weight against height, we first constructed a primary regression evaluation chart for 6-year-old boys, a secondary chart for 6-year-old girls, a secondary chart for 7-year-old boys, and a primary chart for 7-year-old girls. Next, we investigated physical strength of the 6- and 7-year-old girls and boys judged to have obese, standard, and lean body types from the regression charts. No ignificant difference was seen in 6-year-old boys, but significant differences were seen in hanging from a horizontal bar and standing long jump in 7-year-old oys. In 7-year-old girls, a significant difference was seen in sit and reach only. The reasons are conjectured to be that a shift toward obesity from lack of physical activity and a trend toward decreased physical strength occurs with 6 and 7 years as a cutoff time in boys. For girls, it is assumed that no influence on physical strength from body fatness was shown because the burden from natural development due to maturation was large. However, it is thought to be necessary to implement early childhood education while incorporating physical activity as play in the living habits of young children in Korea.

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.

민족 간 신장 차이와 Bergmann법칙의 적용 가능성

藤井勝紀(Fujii, Katsunori),김준동(Kim, Jun-Dong) 한국체육과학회 2021 한국체육과학회지 Vol.30 No.4

Bergmann’s rule(Bergmann, 1847)states that homeothermic animals that live in colder regions such as Northern Europe have larger body sizes with smaller surface area in proportion to body weight in order to minimize heat dissipation. Conversely, in tropical regions body surface area is larger to maximize heat dissipation. For this, shorter heights are advantageous. As to whether this rule applies to humans, surveys of peoples living in cold and tropical regions of the world show that heights tend to be taller in the north and shorter in the south, but simplistic application of Bergmann’s rule cannot always be done in recent years. This is from the effect on physical development of socioeconomic growth in recent years. In the Netherlands, for example, Bergmann’s rule does not apply to height. If one looks only at recent years in this way, a human environmental bias from socioeconomic development is seen and so judgments cannot be made with height alone in each country of Europe today. This human environmental bias can be eliminated applying the secular trend standardization chart for height proposed in this study. Judging the changes in height over the span of about 120 years from 1860 to 1980 with this method allows for evaluation of the height trends in countries located in Northern, Central, and Southern Europe. Heights can then be conveniently explained with Bergmann’s rule. Of course, scientific verification of Bergmann’s rule remains a task for the future.

연령증가에 따른 유아 골밀도의 평가차트 구축

藤井勝紀(Fujii, Katsunori),可兒勇樹(Kani, Yuki),糟谷浩輔(Kasuya, Kosuke),김준동(Kim, Jun-Dong) 한국체육과학회 2018 한국체육과학회지 Vol.27 No.2

A clear method for evaluating bone density findings in young children has not been established. One reason behind this is that the changes with age in bone density during early childhood have not been clarified. In this study, a mixed cohort method was adopted and a least squares approximation polynomial was applied to bone density indices (stiffness, BUA, SOS) of children from 3 to 5 years old. We then attempted to construct a bone density evaluation chart for early childhood by clarifying the changes in bone density with age. The method was to measure bone density in 3, 4, and 5 year-old children, and then analyze the age-related changes in the bone density index data obtained in a mixed cohort. The results showed changes with age in the values for stiffness and SOS. The optimal polynomial obtained with least squares approximation was shown to be a third order polynomial for boys and a fourth order polynomial for girls. Therefore, in the standard regression evaluation chart for stiffness values a third order polynomial was applied for boys and a fourth order polynomial was applied for girls. An evaluation chart was constructed from a 5-grade regression evaluation. Normalization was then seen in the frequency distribution, and the bone density evaluation constructed in this study for young children was seen to be effective. The mixed cohort in this study did not provide fundamentally simple cross-sectional data but rather semi-longitudinal data that included almost all tracking data from the same subjects. Therefore, clarification of the trends in changes with age in stiffness has great significance.