• Education of Primary School Mathematics
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• v.25 no.4
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• pp.329-341
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• 2022

Data collection is crucial to the process of statistical problem solving since it influences the quality of statistical data. However, there is little instruction on data collection in the Korean mathematics curriculum. In this study, we examined how the data were collected and how the data collection method was taught in the Korean mathematics textbooks for 3rd and 4th grades. As a result, the data appeared in these textbooks were collected by using a variety of methods, including surveys, experiments, observations, and secondary data collections. There were not enough instructions on experiments and observations, compared to surveys and secondary data collection. Additionally, as each textbook works with a distinct contents while teaching data collection, it is expected that there would be variations in the levels that students learn in relation to data collection. Based on these findings, we draw some discussion points to determine how to improve the mathematics curriculum in order to effectively teach data collection in the elementary school.

• Journal of Korean Medical classics
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• v.6
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• pp.252-305
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• 1993

I have studied the relation between a Taoist(道家) and the oriental medicine(韓醫學), it is summerized as following. 1. According to the relation between a Taoist(道家) and the oriental medicine, Lao-tzu(老子)' mathematical principle that had an influence on Three yin-three yang(三陰三陽) theory of the oriental medicine, idea of natural philosopy(自然無爲) and the freedom from avarace(無慾) on the oriental medicine. 2. Vital essence and energy theory(精氣設) in a Taoist not only can be seen in Lao-tzu' Do dug gyung(老子道德經), Maengza(孟子), Guanza(管子), but also its principle has something to do with Nei Ching's Vital essence and energy theory(精氣設). 3. Danjungpa(丹鼎派) can be divided into Naedansul(內丹術) which preserves through the breath and Oedansul(外丹術) which makes one a Taoist hermit. If he takes magic portions(金丹), they had a great effect on Yangsanghak(養生學) and was actually concerned with oriental doctors who was known to us. 4. If medicine of Taoism is classified, it can be divided into three categories. Boiled solution(渴液), Pharmacopea "Ben cao"(本草), Acupuncture & moxibustion(針灸), Magic portions(外丹) are used in the first category. Chinese setting-up and Therapeutic exercises(導引), Josik(調息), Naedan(內丹), Byugok(辟榖), Naeshi(內視), Banjung(房中) belong to second category. The religious contents such as Bu(符), Jeum(占), Cheum(籤), Ju(呪), Je(齊), Gido(祈禱), taboo are implied in third category. 5. In the history of the medicine of Taoism and oriental medicine, they are called animism, shamanism, Mu(巫) or Ye(毉), not separated at first period. In the end of junguk(戰國時代), Ye(醫) was clearly distinguished from Mu(巫) and then Mu(巫) was developed into medicine of Taoism and ye(毉) into the present form of oriental medicine. 6. The oriental medicine doctors that are concerned with Taoism are Bakgo(伯高), Geyugu(鬼臾區), Soyu(少兪), Noigong(雷公), Pyujak(篇鵲), Sunuyi(淳于意), Hwata(華陀), Hwangbomil(皇甫謐), Hangang(韓康), Dongbong(童奉), Heuson(許遜), Galhong(葛洪), Dohongyung(陶弘景), Damlan(曇鸞), uyjajang(葦慈藏), Sonsanak(孫思邈), Wanguing(王氷), Jegonghwalbul(濟公活佛), Yuwanso(劉完素), Judonge(朱丹溪), Leesijin(李時珍), Johakmin(趙學敏), Ougu1(吳杰) etc. 7. The view of a human body in the medicine of Taoism affected the oriental medicine on the ground that man was regarded as a microcosm(小宇宙), so he was compared to a nation or heaven and earth. 8. The anatomy of medicine of Taoism gave a detail description of five visceras and each organs, the heart, center of mental function, Mirie(尾閭) which has an relationship to the training of Naedan(內丹修練). In this resrect, as it is accord with the acupunture point of oriental medicine, therefore we can find that Taoism influenced oriental medicine, also explicit study was achieved. 9. Acient people believed that the goo in the human lxxIy, one of the characteristics of the medicine of Taoism cured the patients and then protected him from the disease. If a man was taken ill, they had him cured by making the god's name which corresponded to its disease, calling him communicating with him, and asking him to deprive him of illness. This treatment was used to live and be kept young eternally. In this respects, we can see that they emphasized on the attitude of Bulchiyibeung chimibeung(不治己病治末病) and psychological treatment. 10. Samsi thoery(三尸說) that one's fortune, disaster, health, and disease in the world are at the mercy of his good or bad conduct, is concerned with Taoism and treatment with the oriental medicine. 11. Guchung(九蟲) is more closly associated with the religious aspect rather than with the medical aspect. Because of the similarity of the mcdern parasitism, its study has an important meaning. 12. The respect for the human life is reflected in jeunsi(傳屍), with Samsi-guchung theory(三尸九蟲說), which is considered as mxIern tuberculosis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4296-4311
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• 1977

This study was conducted to derive an Instantaneous Unit Hydrograph for the accurate and reliable unitgraph which can be used to the estimation and control of flood for the development of agricultural water resources and rational design of hydraulic structures. Eight small watersheds were selected as studying basins from Han, Geum, Nakdong, Yeongsan and Inchon River systems which may be considered as a main river systems in Korea. The area of small watersheds are within the range of 85 to 470$\textrm{km}^2$. It is to derive an accurate Instantaneous Unit Hydrograph under the condition of having a short duration of heavy rain and uniform rainfall intensity with the basic and reliable data of rainfall records, pluviographs, records of river stages and of the main river systems mentioned above. Investigation was carried out for the relations between measurable unitgraph and watershed characteristics such as watershed area, A, river length L, and centroid distance of the watershed area, Lca. Especially, this study laid emphasis on the derivation and application of Instantaneous Unit Hydrograph (IUH) by applying Nash's conceptual model and by using an electronic computer. I U H by Nash's conceptual model and I U H by flood routing which can be applied to the ungaged small watersheds were derived and compared with each other to the observed unitgraph. 1 U H for each small watersheds can be solved by using an electronic computer. The results summarized for these studies are as follows; 1. Distribution of uniform rainfall intensity appears in the analysis for the temporal rainfall pattern of selected heavy rainfall event. 2. Mean value of recession constants, Kl, is 0.931 in all watersheds observed. 3. Time to peak discharge, Tp, occurs at the position of 0.02 Tb, base length of hlrdrograph with an indication of lower value than that in larger watersheds. 4. Peak discharge, Qp, in relation to the watershed area, A, and effective rainfall, R, is found to be {{{{ { Q}_{ p} = { 0.895} over { { A}^{0.145 } } }}}} AR having high significance of correlation coefficient, 0.927, between peak discharge, Qp, and effective rainfall, R. Design chart for the peak discharge (refer to Fig. 15) with watershed area and effective rainfall was established by the author. 5. The mean slopes of main streams within the range of 1.46 meters per kilometer to 13.6 meter per kilometer. These indicate higher slopes in the small watersheds than those in larger watersheds. Lengths of main streams are within the range of 9.4 kilometer to 41.75 kilometer, which can be regarded as a short distance. It is remarkable thing that the time of flood concentration was more rapid in the small watersheds than that in the other larger watersheds. 6. Length of main stream, L, in relation to the watershed area, A, is found to be L=2.044A0.48 having a high significance of correlation coefficient, 0.968. 7. Watershed lag, Lg, in hrs in relation to the watershed area, A, and length of main stream, L, was derived as Lg=3.228 A0.904 L-1.293 with a high significance. On the other hand, It was found that watershed lag, Lg, could also be expressed as {{{{Lg=0.247 { ( { LLca} over { SQRT { S} } )}^{ 0.604} }}}} in connection with the product of main stream length and the centroid length of the basin of the watershed area, LLca which could be expressed as a measure of the shape and the size of the watershed with the slopes except watershed area, A. But the latter showed a lower correlation than that of the former in the significance test. Therefore, it can be concluded that watershed lag, Lg, is more closely related with the such watersheds characteristics as watershed area and length of main stream in the small watersheds. Empirical formula for the peak discharge per unit area, qp, ㎥/sec/$\textrm{km}^2$, was derived as qp=10-0.389-0.0424Lg with a high significance, r=0.91. This indicates that the peak discharge per unit area of the unitgraph is in inverse proportion to the watershed lag time. 8. The base length of the unitgraph, Tb, in connection with the watershed lag, Lg, was extra.essed as {{{{ { T}_{ b} =1.14+0.564( { Lg} over {24 } )}}}} which has defined with a high significance. 9. For the derivation of IUH by applying linear conceptual model, the storage constant, K, with the length of main stream, L, and slopes, S, was adopted as {{{{K=0.1197( {L } over { SQRT {S } } )}}}} with a highly significant correlation coefficient, 0.90. Gamma function argument, N, derived with such watershed characteristics as watershed area, A, river length, L, centroid distance of the basin of the watershed area, Lca, and slopes, S, was found to be N=49.2 A1.481L-2.202 Lca-1.297 S-0.112 with a high significance having the F value, 4.83, through analysis of variance. 10. According to the linear conceptual model, Formular established in relation to the time distribution, Peak discharge and time to peak discharge for instantaneous Unit Hydrograph when unit effective rainfall of unitgraph and dimension of watershed area are applied as 10mm, and $\textrm{km}^2$ respectively are as follows; Time distribution of IUH {{{{u(0, t)= { 2.78A} over {K GAMMA (N) } { e}^{-t/k } { (t.K)}^{N-1 } }}}} (㎥/sec) Peak discharge of IUH {{{{ {u(0, t) }_{max } = { 2.78A} over {K GAMMA (N) } { e}^{-(N-1) } { (N-1)}^{N-1 } }}}} (㎥/sec) Time to peak discharge of IUH tp=(N-1)K (hrs) 11. Through mathematical analysis in the recession curve of Hydrograph, It was confirmed that empirical formula of Gamma function argument, N, had connection with recession constant, Kl, peak discharge, QP, and time to peak discharge, tp, as {{{{{ K'} over { { t}_{ p} } = { 1} over {N-1 } - { ln { t} over { { t}_{p } } } over {ln { Q} over { { Q}_{p } } } }}}} where {{{{K'= { 1} over { { lnK}_{1 } } }}}} 12. Linking the two, empirical formulars for storage constant, K, and Gamma function argument, N, into closer relations with each other, derivation of unit hydrograph for the ungaged small watersheds can be established by having formulars for the time distribution and peak discharge of IUH as follows. Time distribution of IUH u(0, t)=23.2 A L-1S1/2 F(N, K, t) (㎥/sec) where {{{{F(N, K, t)= { { e}^{-t/k } { (t/K)}^{N-1 } } over { GAMMA (N) } }}}} Peak discharge of IUH) u(0, t)max=23.2 A L-1S1/2 F(N) (㎥/sec) where {{{{F(N)= { { e}^{-(N-1) } { (N-1)}^{N-1 } } over { GAMMA (N) } }}}} 13. The base length of the Time-Area Diagram for the IUH was given by {{{{C=0.778 { ( { LLca} over { SQRT { S} } )}^{0.423 } }}}} with correlation coefficient, 0.85, which has an indication of the relations to the length of main stream, L, centroid distance of the basin of the watershed area, Lca, and slopes, S. 14. Relative errors in the peak discharge of the IUH by using linear conceptual model and IUH by routing showed to be 2.5 and 16.9 percent respectively to the peak of observed unitgraph. Therefore, it confirmed that the accuracy of IUH using linear conceptual model was approaching more closely to the observed unitgraph than that of the flood routing in the small watersheds.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1813-1818
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• 2014

This paper presents the stability analysis of the haptic system including a human impedance using the Routh-Hurwitz criterion. The reflective force is computed from a virtual spring model and is transferred to a human operator using the first-order-hold method. The stability boundary conditions are induced and the relation among a virtual spring ($K_w$), the mass ($M_h$), the damping ($B_h$) and the stiffness ($K_h$) of a human impedance is analyzed. Hence the stability boundary of the virtual spring ($K_w$) is proposed as $K_w{\leq}54413{\sqrt{(M_h+M_d)(B_h+B_d)}}-0.486K_h$ when the sampling time is 1 ms. The average relative error is about 0.5% when the mathematical analysis results are compared with the results of the stability boundary model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.2
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• pp.355-365
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• 1994

An analytical model of return flow is presented outside the surf zone. The governing equation is derived from the Navier-Stokes equation and the continuity. Each term of the governing equation is evaluated by the ordering analysis. Then the infinitesimal terms, i.e. the turbulent normal stress, the squared vertical velocity of water particle and the streaming velocity, are neglected. The driving forces of return flow are calculated using the linear wave theory for the shallow water approximation. Especially, the space derivative of local wave heights is described considering a shoaling coefficient. The vertical distribution of eddy viscosity is discussed to the customary types which are the constant, the linear function and the exponential function. Each coefficient of the eddy viscosities which sensitively affect the precision of solutions is uniquely decided from the additional boundary condition which the velocity becomes zero at the wave trough level. Also the boundary conditions at the bottom and the continuity relation are used in the integration of the governing equation. The theoretical solutions of present model are compared with the various experimental results. The solutions show a good agreement with the experimental results in the case of constant or exponential function type eddy viscosity.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.21-25
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• 2015

We studied the effects of temperature and salinity on the egg development and larvae of sevenband grouper Epinephelus septemfasciatus under sea cage culturing condition. In regard to rearing environment, the water temperature is $21.5{\sim}23.5^{\circ}C$ (mean $22.0{\pm}0.05^{\circ}C$) and the salinity is 32.0~33.0 psu (mean $32.5{\pm}0.05psu$). The time of egg development was positively proportional to water temperature with 29 hrs, 27 hrs, 24 hrs, 17 hrs, 15 hrs after fertilization in $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$ respectively. Each of the salinity hatching rate was 80% in the section of 15 psu, 81.8% in the section of 25 psu, 89.1% in the section of 30 psu, and 79.1% in the section of 35 psu. All things considered, the highest hatching rate appeared in the range of the section of 25~30 psu. Abnormalities of low salinity section, such as 15 psu (20.0%) and 20 psu (18.2%), was lower than the abnormalities of 35 psu that belongs to high salt section. The relation between the time of egg development (t:hour) and water temperature ($T:^{\circ}C$) was represented by the mathematical formulae. The mean biological minimum temperature was $5.4^{\circ}C$.

• School Mathematics
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• v.19 no.2
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• pp.267-287
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• 2017

Fostering students' positive affect related to mathematics such as attitudes toward mathematics and dispositions toward learning mathematical concepts is one of the major goals of school mathematics programs. In this study, we collected data from students at the 4-1 grade levels to develop an instrument that measures students' affect regarding mathematics learning. To develop the instrument, we first conducted focus group interviews, which we recorded, transcribed, and analyzed. We sorted the results according to seven components of the non-cognitive domain of mathematics learning, which drew from taxonomical constructs of previous research. We then conducted a pilot study in which we administered the instrument as a pretest and a posttest. We chose the final items based on confirmatory factor analysis and a reliability test of the pre and posttest scores. The final instrument contains 24 items, which are classified according to the seven components: interest, attitudes, value, external motivation, internal motivation, learning conation, and efficacy. We anticipate this instrument will be useful for studies that need to measure students' non-cognitive characteristics in relation to learning mathematics.

• Education of Primary School Mathematics
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• v.17 no.2
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• pp.95-111
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• 2014

The purpose of this study is to determine the relationship between metacognition and math creative problem solving ability. Specific research questions set up according to the purpose of this study are as follows. First, what relation does metacognition has with creative math problem-solving ability of mathematically gifted elementary students? Second, how does each component of metacognition (i.e. metacognitive knowledge, metacognitive regulation, metacognitive experiences) influences the math creative problem solving ability of mathematically gifted elementary students? The present study was conducted with a total of 80 fifth grade mathematically gifted elementary students. For assessment tools, the study used the Math Creative Problem Solving Ability Test and the Metacognition Test. Analyses of collected data involved descriptive statistics, computation of Pearson's product moment correlation coefficient, and multiple regression analysis by using the SPSS Statistics 20. The findings from the study were as follows. First, a great deal of variability between individuals was found in math creative problem solving ability and metacognition even within the group of mathematically gifted elementary students. Second, significant correlation was found between math creative problem solving ability and metacognition. Third, according to multiple regression analysis of math creative problem solving ability by component of metacognition, it was found that metacognitive knowledge is the metacognitive component that relatively has the greatest effect on overall math creative problem-solving ability. Fourth, results indicated that metacognitive knowledge has the greatest effect on fluency and originality among subelements of math creative problem solving ability, while metacognitive regulation has the greatest effect on flexibility. It was found that metacognitive experiences relatively has little effect on math creative problem solving ability. This findings suggests the possibility of metacognitive approach in math gifted curricula and programs for cultivating mathematically gifted students' math creative problem-solving ability.

• Education of Primary School Mathematics
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• v.13 no.2
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• pp.85-97
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• 2010

The purpose of this study is to develop a teaching program in consideration of the geometrical thinking levels of students to make a contribution to teaching figures effectively. To do this, we checked the geometrical thinking levels of fourth-graders, developed a teaching program based on van Hiele's theory, and investigated its effect on their geometrical thinking levels. The teaching program based on van Hiele's theory put emphasis on group member interaction and specific activities through offering various geometrical experiences. It contributed to actualizing activity-centered, student-oriented, inquiry-oriented and inductive instruction instead of sticking to expository, teacher-led and deductive instruction. And it consequently served to improving their geometrical thinking levels, even though some students didn't show any improvement and one student was rather degraded in that regard - but in the former case they made partial progress though there was little marked improvement, and in the latter case she needs to be considered in relation to her affective aspects above all. The findings of the study suggest that individual variances in thinking level should be recognized by teachers. Students who are at a lower level should be given easier tasks, and more challenging tasks should be assigned to those who are at an intermediate level in order for them to have a positive self-concept about mathematics learning and ultimately to foster their thinking levels.

• Korean Journal of Childcare and Education
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• v.7 no.3
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• pp.259-284
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• 2011

This thesis examined the effects of social demographical variables, multiple intelligences, and creative home environment on the child leadership. Study samples are 5 years old children at the kindergartens located in Seoul and metropolitan areas as well as their parents and (homeroom) teachers. 173 copies were analyzed. Results of this study are as follows: First, in terms of difference of multiple intelligences, creative home environment and child leadership depending on social demographical background, The second child showed significantly different interpersonal intelligence among other multiple intelligences from the first child with regard to the birth order. In terms of mother's education level and creative home environment, mothers with education more than universities showed big difference in family pressure. In terms of effects of total income, the children from families with total income over 4 million won showed significant difference in logical, mathematical, naturalist intelligence. and language intelligence. In terms of creative home environment, significant difference was found with regard to learning environment and child respect. Second, multiple intelligences, creative home environment, and child leadership showed correlated strongly. Third, total income in social demographic variables, language intelligence in multiple intelligences, and family pressure in creative home environment were found to have effects on it. Total income in social and demographical variables and family pressure in creative home environment were found to have effects on it. Interpersonal relation intelligence in multiple intelligences and learning environment in creative home environment were found to have effects on it. Total leadership had effects on family pressure only in creative home environment.