• Title/Summary/Keyword: repeated addition

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The Characteristics of Elementary School Students' Prediction Changes by the Suggestion Types for Situation in Repeated Anomalous Situation - Focused on Buoyancy - (반복되는 불일치 상황에서 상황 제시 방법에 따라 초등학생들이 예상을 바꾸는 특성)

  • Jeon, Ah-Reum;Noh, SukGoo;Park, Jae-Keun
    • Journal of Korean Elementary Science Education
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    • v.31 no.3
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    • pp.298-310
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    • 2012
  • The purpose of this study was to analyze the characteristics of elementary school students' prediction changes by the suggestion types in a multiple anomalous situation. We investigated the responses, the rate and time of changing prediction, and cognitive conflicts of the students when repeated anomalous situation was suggested in experimental or logical way in science classes focused on buoyancy. As the anomalous situation was repeated, the students to change the prediction increased in number and also the rates to choose the correct prediction became higher. The group who was exposed in experimental way changed their prediction more than in logical way. In addition, when we classified the students to change the prediction by types, the group in experimental way showed higher rate of NM, MM type and FFT type. With anomalous situation repeated, cognitive conflicts of the students has been gradually declining in both groups. But it seemed that the group in experimental way experienced higher mental conflicts. In particular, as students changed the prediction more and arrived at the correct answer after changing their prediction, all the more so. It is concluded that the degree of students' changing prediction and experiencing cognitive conflict can be different according to the suggestion types for situation. Therefore the correlation with cognitive conflict factors can be also observed with the types of students' reactions.

Repeated Dose Oral Toxicity Study of Alismatis Rhizoma in SD Rats (택사(Alismatis Rhizoma) 추출물의 반복 경구투여 독성 연구)

  • Roh, Hang-Sik;Seok, Ji-Hyun;Jeong, Ja-Young;Lee, Jong-Kwon;Kim, Tae-Sung;Choi, Hye-Kyung;Ha, Hun-Yong
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.27 no.1
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    • pp.79-90
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    • 2014
  • Objectives : This study was carried out to evaluate the repeated dose oral toxicity of Alismatis Rhizoma in Sprague-Dawley(SD) rats. Methods : Male and female rats were administered orally with Alismatis Rhizoma water extract of 500 mg/kg(low dosage group), 1,000 mg/kg(middle dosage group) and 2,000 mg/kg(high dosage group). We daily observed number of deaths, clinical signs and gross findings for 14 days(twice a day). After 14 days, we measured body and organs weight. Also we analyzed hematological changes. Results : No dead SD rats and no clinical signs were found during the experiment period. Also other specific changes were not found between control and treated groups in hematology and serum biochemistry. In addition no significant changes of gross body and individual organs weight. Conclusions : These results suggest that water soluble extract of Alismatis Rhizoma has not repeated dose oral toxicity and oral LD50 value was over 2,000 mg/kg in SD rats. As a result, we can determine Alismatis Rhizoma is a relatively safe substance.

Physical Property of Carbon Fiber Reinforced Thermoplastic Polymer based Composites by Repeating Processing of PP Composition (PP 복합 조성물의 반복 가공에 의한 열가소성 폴리머 탄소섬유 강화 복합재료의 물리적 특성 변화 연구)

  • Jin-Woo Lee;Jae-Young Lee;Seoung-Bo Shin;Jae-Hyung Park;Hyun-Ju Park;Kyung-Hun Oh;Jin-Hyuk Huh;Yun-Hae Kim;Ji-Eun Lee
    • Composites Research
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    • v.37 no.2
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    • pp.68-75
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    • 2024
  • Polypropylene (PP), a thermoplastic resin with excellent mechanical, thermal, chemical, and water resistance properties, has been attracting attention due to its economic efficiency and recyclability. However, repeated processing of thermoplastic resins can lead to property degradation, and the point at which quality degradation occurs varies depending on the processing conditions. In this study, we evaluated the performance changes of composite materials with repeated processing by blending PP resin with various additives and conducting extrusion and injection processes repeatedly. In addition, we evaluated the mechanical properties of composite materials to evaluate the effect of MFI value change during repeated processing on fiber impregnation in composite material processing.

Exploring the process of learning mathematics by repeated reading: Eye tracking and heart rate measurement (반복 읽기를 이용한 수학 학습의 과정 분석: 시선의 움직임 추적과 심박수 측정을 중심으로)

  • Lee, Bongju;Lee, Se Hyung
    • Journal of the Korean School Mathematics Society
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    • v.24 no.1
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    • pp.59-81
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    • 2021
  • This study aimed to investigate how the learners' mathematics learning processes change with repeatedly reading mathematical text. As a way to teach and learn mathematics, we also wanted to examine the effect of repeated reading and to explore the implications for a more efficient teaching and learning strategy. To help us with this study, we mainly used eye tracking and heart rate (HR) measurement. There were four cycles in a cycle of repeated reading, and the number of repeated readings for all cycles was fixed to three times. Eight prospective mathematics teachers in the Department of Mathematics Education of a National University in South Korea participated. Data were analyzed in five aspects: (1) the total reading time per round, the total reading time per slide; (2) the change trends of total reading time per round and slide; (3) the order of slides read; (4) the change trends of HR per round. We found that most participants read in a similar pattern in the first reading, but the second and third reading patterns appeared more diverse for each learner. Also, the first reading required the most time regardless of the repeat cycle, and the time it took to repeatedly read afterward varied depending on the individual. Based on the findings of this study, the most primary conclusion is that self-directed mathematics learning by using repeated reading is effective regardless of cycle. In addition, we suggested four strategies to improve the efficiency of this teaching and learning method.

An Alternative Program for the Teaching of Multiplication Concept Based on Times Idea (배 개념에 기초한 자연수 곱셈 개념의 지도 방안)

  • Kang, Heung-Kyu
    • School Mathematics
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    • v.11 no.1
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    • pp.17-37
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    • 2009
  • Concept and model of multiplication is not single. Concepts of multiplication can be classified into three cases: repeated addition, times idea, pairs set. Models of multiplication can be classified into four cases: measurement, rectangular pattern, combinatorial problem, number line. Among diverse cases of multiplication's concept and model, which case does elementary mathematics education lay stress on? This question is a controvertible didactical point. In this thesis, (1) mathematical and didactical analysis of multiplication's concept and model is performed, (2) a concrete program of teaching multiplication which is based on times idea is contrived, (3) With this new program, the teaching experiment is performed and its result is analyzed. Through this study, I obtained the following results and suggestions. First, the degree of testee's understanding of times idea is not high. Secondly, a sort of test problem which asks the testee to find times value is more easy than the one to find multiplicative resulting value. Thirdly, combinatorial problem can be handled as an application of multiplication. Fourthly, the degree of testee's understanding of repeated addition is high. In conclusion, I observe the fact that this new program which is based on times idea could be a alternative program of teaching multiplication which could complement the traditional method.

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Assessment and Interpretation of Bioequivalence for Two Drug Formulations using Crossover Design

  • Ko, Seoung-gon;Oh, Hyun-Sook
    • Communications for Statistical Applications and Methods
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    • v.6 no.2
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    • pp.601-610
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    • 1999
  • Crossover design is officially except for special occasions recommended by KFDA and FDA for assessing Bioequivalence between two drugs one for reference and the other for innovator. Such design is regarded as a special case of latin square split-polt or repeated measurement design and its main difference with other designing methods is that each subject in an experiment is exposed two drugs in sequence. Therefore general statistical analysis is not suitable since the model for this experiment includes carryover effect in addition to period and sequence effect. in this paper analysis for crossover model with two drugs and its interpretation are mainly discussed and an example is given for illustration.

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A Method of Reducing EMI in LCD Timing Controller using Efficient Data Compression and Data Transition

  • Kim, Min-Kyu;Lee, Song-Jae;Kim, Chang-Gone;Kang, Sin-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1499-1502
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    • 2008
  • This paper proposes an efficient data compression for the conventional method of reducing EMI in a 10 bit LCD timing controller (TCON). In addition, we develop a new method to reduce EMI in a LCD TCON through repeated data on adjacent blocks. The novel technique reduced EMI by 10 dB for a 52" FHD 10it LCD TV.

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Korean vowel recognition in noise using auditory model

  • Shim, Jae-Seong;Lee, Jae-Hyuk;Yoon, Tae-Sung;Beack, Seung-Hwa;Park, Sang-Hui
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.1037-1040
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    • 1988
  • In this study, we performed the recognition test on Korean vowel using peripheral auditory model. In addition, for the purpose of objective comparision, the recognition test is performed by extracting LPC cepstrum coefficients from the same data. And the same speech data are mixed with the Guaussian white noise quantitatively, then we repeated the same test, too. So we verified that this auditory model has a adaptability on noise.

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Single and 28-day repeated dose toxicity studies of botulinum toxin type A in mice and rats (마우스 및 랫드에서 botulinum toxin type A의 단회 및 28일 반복투여 독성시험)

  • Jeon, Tae-Won;Kim, Ji-Young;Hyun, Sun-Hee;Kim, Nam-Hee;Lee, Sang-Kyu;Kim, Chun-Hwa;Woo, Hee-Dong;Yang, Gi-Hyeok;Jung, Hyun-Ho;Jeong, Tae-Cheon
    • Korean Journal of Veterinary Research
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    • v.43 no.1
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    • pp.57-66
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    • 2003
  • Single and 28-day repeated dose toxicity studies of botulimnn toxin type A were carried out in ICR mice and Sprague-Dawley rats, respectively. In the single dose toxicity study, botulinwn toxin was injected intraperitoneally to male and female mice at a single dose of 40, 59, 89 133 and 200 ng/10 ml saline/kg. All animals died from 59 ng/kg group. Some clinical signs, such as decrease in locomotor activity, dyspnea, prone position and ptosis, were observed in most of both sexes from 59 ng/kg group, but no signs were seen in all animals at 40 ng/kg group. The results showed that the median lethal dose of botulinum toxin might be in the range of 40-59 ng/kg in both sexes. In the repeated dose toxicity study, the test material was administered intradermally for 28 days at doses of 0 (vehicle-treated control), 1.25, 2.5, 5.0 and $10.0ng/head/50{\mu}{\ell}$ saline in male and female rats. No test material-related changes were noted in survivals, clinical signs, food and water consumptions and gross finding in any group. Botulinum toxin treatment significantly decreased the body weight gain rate in male of 5.0 ng/head group and over and in female of 10.0 ng/head group compared to vehicle-treated control. One or more relative organ weights (i.e., spleen, thymus, liver and kidney) were increased significantly from 5.0 ng/head group compared to vehicle-treated control in both sexes. Serum biochemistry revealed increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase, total protein and albumin in male, and increases in AST and ALT and decreases in $K^+$ and $Cl^-$ in female without dose-pendent manners. In the histopathological study, physical stimulation by needle caused slight inflammations of dennis. In addition, botulinum toxin treatment induced denervation of nerve cell and disuse of muscle, resulting in atrophy of skeletal muscle in both sexes from 2.5 ng/head group. When the antibodies to toxin were determined in all animals, a significant increase in serum antibodies was observed from 5.0 ng/head group. The results showed that the NOAEL of botulinum toxin might be 1.25 ng/head for 28-day repeated dose toxicity in rats.

Single-Dose Toxicity and Four Week Repeated-Dose Toxicity Study on Tensolin-F® (3,9-diferuloyl-6-oxopterocarpen) (Tensolin-F® (3,9-diferuloyl-6-oxopterocarpen)의 단회 독성시험 및 4주 반복투여 독성시험)

  • Kim, Keun-Su;Park, Sung-Min;Lee, Nam-Jin;Pyo, Hyeong-Bae;Chai, Hee-Yul;Jung, Yu-Ri;Lin, Chun-Mai;Kim, Sun-Hee;Lee, Hye-Young;Kang, Jong-Koo
    • Toxicological Research
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    • v.23 no.4
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    • pp.405-413
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    • 2007
  • This study was to investigate single and repeated-dose toxicities of Tensolin-$F^{(R)}$, an anti-wrinkle agent, in Sprague-Dawley (SD) rats or ICR mice. In single-dose oral toxicity study, the test materials were administered once by gavage to male and female SD rats at dose levels of 0 and 2,000 mg/kg. No dead animals and abnormal necropsy findings were found in control and Tensolin-$F^{(R)}$ treated group. Therefore, the approximate lethal dose of Tensolin-$F^{(R)}$ was considered to be higher than 2,000 mg/kg in rats. In the 4-week repeated oral toxicity study, the test material was administered once daily by gavage to male and female ICR mice at dose levels of 0, 25, 50 and 100 mg/kg/day for 4-weeks. In the results, no abnormality was observed in mortality, clinical findings, body weight changes, food and water consumptions, opthalmoscopic findings, necropsy findings, histopathological findings. In hematological analysis, there was a trend of increase in reticulocyte at male 25 mg/kg, although such changes were in normal ranges. On the other hand, there was a trend of decrease in hemoglobin at female 50, 100 mg/kg, such changes were in normal ranges. In addition, serum biochemical parameters including sodium, BUN and chloride increased at 25, 50 and 100 mg/kg. Relative organ weights of right testis, brain, lung and left epididymis were increased in 100 mg/kg groups of male rats in contrast to not change in female groups. However, these changes of relative organ weights, hematological and serum biochemical parameters were not accompanied with related signs such as histopathological changes or clinical findings. In conclusion, 4-week repeated oral dose of Tensolin-$F^{(R)}$ to ICR mice did not cause apparent toxicological change at the dose of 25, 50, 100 mg/kg body weight. Consequently the no-observed-adverse-effect level (NOAEL) for Tensolin-$F^{(R)}$ in ICR mice following gavage for at least 4-week is higher than 100 mg/kg/day.