• Title/Summary/Keyword: repetition

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Consolidation Characteristics of Repeated Increasing and Decreasing Load in Marine Clay (해성점토의 반복재하 및 제하압밀특성)

  • 주재우;김재영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.24 no.3
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    • pp.84-91
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    • 1982
  • This study was conducted to investigate the consolidation characteristics of repeated increasing and decreasing load m marine clay. Consolidation test was performed by the whole repetition of increasing and decreasing load and the partial repetition of increasing and decreasing load. The results obtained were as follows: 1. The void ratio e was decreased according to the increase of preloading and the repe- tition of increasing and decreasing load. 2. In case of the partial repetition of increasing and decreasing load the compression index Cc was decreased with the increase of preloading and the repetition of increa- sing and decreasing load 3. The expansion rate was greatly increased with the whole repetition of increasing and decreasing load and it was inclined to be increased with the increase of preloading in case of the partial repetition. 4. The coefficient of volume compressibility were decreased according to the repetition of increasing and decreasing load 5. The secondary consolidation coefficient was decreased with the repetition of increasing and decreasing load. Especially in case of the partial repetition, the peaks of secon- dary consolidation curves could be found to move toward the vicinity of preloading.

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Effect of Laser Pulse Repetition Rate on the Electrical Properties of $Pb(Zr_{0.48}Ti_{0.52})O_3$ (PZT) Thin Films grown by Pulsed Laser Deposition (펄스 레이저 증착법에 의해 제작된 Laser pulse repetition rate의 변화에 따른 $Pb(Zr_{0.48}Ti_{0.52})O_3$ (PZT) 박막의 전기적 특성)

  • Li, Dong-Hua;Lee, Sang-Yeol
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.11-12
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    • 2005
  • [ $Pb(Zr_{0.48}Ti_{0.52})O_3$ ] (PZT) thin films were deposited on Pt(111)/Ti/$SiO_2$/Si substrates by pulsed laser deposition. In order to study the effect of different laser pulse repetition rate on the dielectric and ferroelectric properties of PZT thin films,2 Hz and 5 Hz of laser pulse repetition rate were selected. We compared the results of XRD pattern, dielectric constant and hysteresis characteristics. From the experimental data, we found that the electrical properties of PZT thin films which grown ar 2 Hz of laser pulse repetition rate were better than those which grown at 5 Hz of laser pulse repetition rate.

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A Study on the Performance Analysis of Pulse Repetition Frequency Jitter Compensation for Generating Doppler Profile (도플러 프로파일 생성을 위한 펄스 반복주파수 지터 보상 성능분석에 대한 연구)

  • Lee, Jung-Won;Hwang, Kyu Young
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.3
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    • pp.213-220
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    • 2020
  • This paper proposes a method on the performance analysis of pulse repetition frequency jitter compensation for generating Doppler profile. Exact phase compensation of each pulse is required to obtain Doppler profiles under pulse repetition frequency jitter. Three parameters such as velocity, pulse repetition frequency, and carrier frequency are examined to cause errors when conducting the pulse repetition frequency jitter compensation, then assuming well-focused Doppler profiles reflect well-conducted pulse repetition frequency jitter compensation, the proposed method in this paper utilizes the contrast to measure how well Doppler profile is generated. These are validated by electromagnetic computation data and computer simulation. Then, it is concluded which parameter is important on the performance analysis of pulse repetition frequency jitter compensation by using the contrast.

Learning Outcomes Analysis Using by Degree of Concept and Repetition Learning of Motion Mechanics (운동 역학의 개념형성 정도와 재학습을 통한 학습효과 분석)

  • Jang, Seok-Jeong;Lee, Jongkil
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.4 no.2
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    • pp.46-52
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    • 2012
  • In this study, middle school students, from 1st to 3rd grade, who already completed section of the 'force and motion' are targets. Based on the survey of the students following conclusions are obtained using by 'before and after' of repetition learning. First, through the pre-test results and measured the degree of concept, repetition learning was found to be effective. Second, through the post-survey after repetition learning science concerning was increased rather than before learning. Improved confidence through the repetition learning effect should contribute learning effect.

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A Study on Destruction Characteristics of BJT (Bipolar Junction Transistor) at Different Pulse Repetition Rate (다양한 펄스 반복률에서의 NPN BJT (Bipolar Junction Transistor)의 파괴 특성에 관한 연구)

  • Bang, Jeong-Ju;Huh, Chang-Su;Lee, Jong-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.3
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    • pp.167-171
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    • 2014
  • This paper examines the destruction behavior of NPN BJT (bipolar junction transistor) by repetition pulse. The injected pulse has a rise time of 1 ns and the maximum peak voltage of 2 kV. Pulse was injected into the base of transistor. Transistor was destroyed, current flows even when the base power is turned off. Cause the destruction of the transistor is damaged by heat. Breakdown voltage of the transistor is 975 V at single pulse, and repetition pulse is 525~575 V. Pulse repetition rate increases, the DT (destruction threshold) is reduced. Pulse Repetition rate is high, level of transistor destruction is more serious.

Psychophysical Stess Depending on Repetition of Wrist Motion and External Load (손목 동작의 반복과 외부 부하에 따른 심물리학적 부하)

  • Kee, Do-Hyung
    • Journal of the Korean Society of Safety
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    • v.19 no.4
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    • pp.123-128
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    • 2004
  • This study investigated effect of arm posture, repetition of wrist motion and external load on perceived discomfort. The arm postures were controlled by shoulder flexion, elbow flexion, and ist motions such as flexion, extension, radial deviation and ulnar deviation. An experiment was conducted to measure discomfort scores for experimental treatments using the magnitude estimation, in which the L16 orthogonal array was adopted for reducing the size of experiment. The results showed that while the effect of the shoulder flexion, repetition of wrist motion and external load was statistically significant at $\alpha=0.05$or 0.10, that of the elbow and wrist motions was not. Discomfor ratings increased linearly as levels of wrist repetition and external load increased. This implies that the existing posture classification schemes such as OWAS, RULA, which do not properly consider effect of motion repetition and external load, may underestimate postural load. Based on the regression equation for wrist repetition and external load, isocomfort region indicating the region within which discomfort scores were expected to be the same was proposed. It is recommended that when assessing risk of postures or developing new posture classification schemes, motion repetition and external load as well as posture itself be fully taken into consideration for precisely evaluating postural stress.

Evaluation of the Relationship Between Family History of Breast Cancer and Risk Perception and Impacts on Repetition of Mammography

  • Khoshravesh, Sahar;Taymoori, Parvaneh;Roshani, Daem
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.sup3
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    • pp.135-141
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    • 2016
  • Since the mean age of breast cancer in women living in developing countries, compared with those in developed countries, is lower by about 10 years, repetition of mammography can play an important role in reducing morbidity and mortality. Hence, this study aimed to investigate the relationship between family history of breast cancer and risk perception and its impact on repetition of mammography. In this cross-sectional study, 1,507 women aged 50 years and older, referred to the mammography center of Regions 1 and 6 in Tehran, Iran, were enrolled. Data were collected using a self-report questionnaire and analyzed using SPSS and LISREL. According to our findings, knowledge about the time interval of mammography was found to have the highest correlation with repetition of mammography (r=0.4). Among the demographic variables, marital status (${\beta}$= -0.1) and family history of breast cancer (${\beta}$=0.1) had the most direct and significant impact on repetition of mammography (P <0.05). Among the other variables studied, knowledge (${\beta}$=-0.5) had the highest direct and significant impact on repetition of mammography (P <0.05). Family history of breast cancer was one of the predictors of repetition of mammography, but the results did not prove any relationship with risk perception. Further studies are needed to assess the effect of risk perception and knowledge about time interval on the initiation and continuation of mammography.

The Relationship between the Performance of Sentence Repetition and Sentence Production in School-age Children (학령기아동의 문장따라말하기와 문장산출 능력과의 관계)

  • Heo, Hyun-Sook;Lee, Yoon-Kyung
    • Phonetics and Speech Sciences
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    • v.2 no.1
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    • pp.127-133
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    • 2010
  • The purpose of the present study was to examine the relationship between sentence repetition and sentence production in school-age children. The participants included 120 school-age children through 1st to 6th grades who were then divided into three grade groups (lower grade: 1st to 2nd grades, intermediate grade: 3th to 4th grades, and higher grade: 5th to 6th grades). The repetition task consisted of 32 sentences that were classified by sentence length (5, 6, 7, and 8 words) and structure (conjunctive and embedded sentences). The sentence production task utilized Lee's (2007) grammaticality judgement and sentence combining task. The findings of present study were as follows. (1) The higher grade performed significantly better than the lower and intermediate grades. (2) The participants performed significantly worse when imitating longer sentences than when imitating shorter ones. In addition, there were interaction effects between grade groups and sentences length. (3) The participants performed significantly better when imitating conjunctive rather than embedded sentences. (4) There was significantly positive correlation between the sentence repetition and sentence production task.

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A Case Study on Engineering Education using Intuition and Verbal Repetition (직관과 구술반복을 활용한 공학교육 사례 연구)

  • Ma, Jeong Beom
    • Journal of Engineering Education Research
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    • v.16 no.4
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    • pp.30-36
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    • 2013
  • Applying intuitive learning method on engineering education, especially for the mechanical engineering, is hardly found from the previous case studies and is not easily proved its beneficial verification. Verbal repetition is also rarely used to investigate its positive effects on educational methodology for both science and engineering disciplines. To prove the education effects of these two methods; we used intuitive thinking time period at the beginning of each lecture and let students repeat the concepts and the equations verbally. These two methods were related to the subjects of each lecture, and were used for students to try to draw engineering thinking from natural phenomena that they could easily experience in daily life. The methods could help them to memorize theoretical ideas. We investigated the effects of intuition and verbal repetition methods by comparing the scores of final exam with those of midterm exam. The results revealed significant improvement; 77.6% of the students achieved higher score in their final exam compared to midterm exam. We plan to investigate qualitative contributions of intuition and verbal repetition methods to the students' achievement for the further research.

A Study on the Formative Feature Characteristics of Domestic Minimalism Fashion (국내 미니멀리즘 패션의 조형성에 관한 연구)

  • 최해주;정영선
    • Journal of the Korean Society of Costume
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    • v.51 no.7
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    • pp.93-109
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    • 2001
  • Fashion photographs from leading monthly fashion magazines in 1960s and 1990s were analyzed here. The formative feature characteristics of domestic minimalism fashion were studied. The major conclusions of the study are as follows 1. The formative feature characteristics of minimalism were expressed as simplicity, minimum, repetition, and futurism. 2. The formative feature characteristics of domestic minimalism fashion were expressed as simplicity, minimum, repetition, and futurism in silhouette, shape, detail, trimming, materials, patterns and color. 3. Minimalism in art and domestic fashion were identified to have a relation in the characteristics of formative feature. In shape and color. simplicity and minimum showed analogy while repetition and futurism showed difference. 4. Simplicity and minimum were expressed in both domestic and foreign minimalism fashions, but repetition and futurism were less expressed in domestic fashion.

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