• Title/Summary/Keyword: Repetition

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A Study for Mutual Interference Between Circular Inclusion and Crack in Finite-Width Plate by Boundary Element Method (경계요소법에 의한 유한폭 판재내의 원형 함유물과 균열의 상호간섭에 대한 연구)

  • 박성완
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1474-1482
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    • 1994
  • In order to study the influence of a circular inclusion on a stress field neat a crack tip, mutual interference of a crack and the circular inclusion is analyzed by using the two dimensional boundary element method program made for the analysis of a bimaterial inclusion. The stress intensity factor of an inclusion which has small stiffness is a little greater than that of large stiffness in the near-by crack tip, and similar values tends to appear for distant crack tips. A line crack shows the repetition phenomena which caused by stress mutual interference depending on the radius and stiffness of an inclusion, and the repetition phenomena becoms weak in the inclusion which has large stiffness. Stress mutual interference shows repetition phenomena after extension of a line crack by the length of the radius of the inclusion which has small stiffness.

Disfluency in Language Development (언어발달 과정에 나타난 비유창성 연구)

  • Kim, Tae-Kyung;Chang, Kyung-Hee
    • MALSORI
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    • no.67
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    • pp.61-77
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    • 2008
  • The purpose of this study is to blow the characteristics of disfluency in childhood. The subjects were 144 normal children at the age of between 3 to 8 years who lived in Seoul. All the subjects provided spontaneous conversational speech samples during free-play interactions with their friends. We investigated the patterns and the frequency of disfluency and its relevance with subject's age, speaking rate and MLU(mean length of utterance). The results of this study can be summarized as follows. (1) There was no difference in the frequency of disfluency with the speaker's age or speaking rate. (2) Interjection was the most frequently occurring pattern of disfluency. (3) Prolongation, revision, interjection increased with age while part-word repetition, single-syllable word repetition, multi-syllable word repetition decreased gradually. (4) A significant effect of MLU on the frequency of disfluencies were demonstrated. The regression analysis has shown that more disfluencies occurred in utterances of children whose MLU is longer.

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An Application Based on Smart Device for Special Effect Shooting of Movies

  • Chung, Myoungbeom
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.7
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    • pp.39-46
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    • 2016
  • In this paper, we proposed an application which can conduct to take repetition images for special effect shooting at movies or drama using Bluetooth of smart device. The proposed application can move a camera with motors several times as the same moving after saving of the control data based on the application during specific time using Bluetooth. At the repetition moving, we do not permit to control motors of the camera by person for keeping the same start position and end position after saving the moving data. The camera motors are only moved remotely by saving data of the proposed application. We developed the proposed application and a hardware which works motors with camera to check performance evaluation. Then, we confirmed that the proposed application exactly did the same moving to the motors with camera several times according to saved data. Therefore, because the proposed application can take a same images as control remotely the motors of camera, it will be a useful technology for special effect shooting of movies or dramas.

Distributed Storage Codes with Multiple Replication Degrees Using Relative Difference Families (상대 차족을 이용한 복수 반복 차수 분산 저장 부호)

  • Park, Hosung;Kim, Cheol-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.12
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    • pp.1768-1770
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    • 2016
  • In this paper, we propose a construction method of fractional repetition codes, a class of distributed storage codes, using relative difference families. The proposed codes can support multiple replication degrees for data symbols. It is shown via simulation that the proposed codes store more data than the random fractional repetition codes.

The Repetition rate and Pulse-width control of Nd:YAG laser using One-Chip Microprocessor (One-Chip 마이크로프로세서를 이용한 Nd:YAG 레이저의 반복율 및 펄스폭제어)

  • Hong, J.H.;Chung, Y.H.;Yang, D.M.;Kim, W.Y.;Kim, H.J.
    • Proceedings of the KIEE Conference
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    • 1998.07e
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    • pp.1696-1698
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    • 1998
  • Pulsed Nd:YAG laser using Nd:YAG crystal operates stably in the thermal conductivity, mechanical, optical condition. That is used broadly in material processings because of easy reaction to the materials, and the maintenance is very easy because of lamp excitation. In these material processings, power dinsity control is very important to improve processing technology. Power density is controled by inductance and capacitance or repetition rate. Therefore we are going to control laser power density as One-Chip Microprocessor(PIC16C55) and 8051. We have been experimented at the pulse repetition rate range of 10pps to 60pps(pulse per second).

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Repetition-Rate Multiplication of a 10-GHz Mode-Locked Laser via Coding the Spectral Intensity and Phase

  • Kim, Ik Hwan;Cho, Il Hwan;Hong, Sang Jeen;Seo, Dong-Sun
    • Journal of the Optical Society of Korea
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    • v.18 no.5
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    • pp.611-615
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    • 2014
  • We report high-speed pulse train generation from a relatively low-speed 10-GHz mode-locked laser by means of line-by-line spectral coding. To increase the pulse repetition rate multiplication (RRM) factor, we combine coding schemes for both spectral intensity and phase by placing a simple mask at the coder focal plane. The resulting RRM factor, determined by multiplying the RRM factors of the individual coding schemes, rises as high as 16. To verify the generated pulses, the optical spectra and autocorrelation traces are examined.

Properties of PD Pulses Accompanying with Bush-type Tree in LDPE (저밀도 폴리에틸렌에서 부시형 전기트리에 수반되는 부분방전 펄스의 특성)

  • 강성화;박영국;정수현;이광우;임기조
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.12
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    • pp.1055-1059
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    • 1998
  • The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $\psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.

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Implementation of the Variable Output Laser Diode Driver Synchronized with a Pulse Repetition Frequency Code (펄스 반복 주파수 코드에 동기된 출력 가변형 레이저 다이오드 드라이버 구현)

  • Lee, Young-Ju;Kim, Yong-Pyung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.5
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    • pp.746-750
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    • 2015
  • In this paper, we propose a simulator to evaluate the performance of the semi-active laser guidance or the quadrant photodetector and to simulate the laser power reflected from a target. The laser pulse repetition frequency was generated and synchronized with the laser pulse repetition(PRF) code. To evaluate the performances of the proposed methods, we implemented a prototype system and performed experiments. As a result, the generated high voltage was variable in the range of DC 3V to 340V and has the rate of change of 2000 V/s. PRF code can be generated within 50ms ∼ 100ms and the error is implemented within 0.3ns. The laser output is synchronized with the PRF code and has a dynamic range of 23.6dB.

Dynamics of the IBR-2M reactor at a power pulse repetition frequency of 10 Hz

  • Yu.N. Pepelyshev;D. Sumkhuu
    • Nuclear Engineering and Technology
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    • v.55 no.9
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    • pp.3326-3333
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    • 2023
  • The results of the analysis of a mathematical modeling for the IBR-2M pulsed reactor dynamics for a transition from a power pulse repetition frequency of 5 Hz-10 Hz are presented. The change in the amplitude response of the reactor for variable pulse delayed neutron fraction was studied. We used a set of power feedback parameters determined experimentally in 2021 at an energy output of 1820 MW·day. At a pulse repetition frequency of 10 Hz, the amplitude of pulse energy oscillations significantly depends on the value of the delayed neutron fraction in pulse βp. Depending on βp both suppression and amplification of reactor power fluctuations in the frequency ranges of 0.05-0.20 and 1.25-5.00 Hz can be realized.

ANALYSIS OF ER:YAG LASER IRRADIATION ON CUTTING EFFICACY AND TEMPERATURE CHANGES OF DENTIN (Er:YAG 레이저의 상아질 삭제효과 및 이에 따른 온도변화)

  • Im, Kwang-Ho;Lee, Chang-Seop;Lee, Sang-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.28 no.1
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    • pp.32-44
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    • 2001
  • The purpose of this study was to investigate the effects of Er : YAG laser on cutting efficacy and temperature changes of dentin. We used the dentin specimens of human premolars and molars which contain the physiologic saline and maintain the pulpal pressure in dentinal tubules. Each specimen was exposed to Er : YAG laser with non-contact handpiece type delivery system under different treatment condition of irradiation energy, pulse repetition rate, and exposure time. Two procedures were conducted by the presence of water flow during lasing. The specimens were grouped by thickness of dentin. We investigated the cavity pattern, volume, and temperature change of dentin specimen to determine the cutting efficacy and temperature rise of Er : YAG laser, and obtained following results. 1. Cutting volume of dentin was increased by increasing the irradiation energy, pulse repetition rate, and exposure time(P<0.05). 2. Margins of abulated cavities were sharp and clean and floors of cavities were conical in shape and showing smooth surfaces. Upper diameter of abulated cavities were increasing as laser parameter of irradiation energy, pulse repetition rate, and exposure time were increased. A few cracks were observed on abulated surfaces under treatment condition of laser parameter with 150mJ, 5Hz, and 5sec. 3. Temperature was increased as laser parameter of irradiation energy, pulse repetition rate, and exposure time were increased, and temperature rise was decreased as dentin thickness was increased(P<0.05). 4. Temperature rise was decreased under water flow compared with no water flow during laser exposure(P<0.05). From these results, we think that the method of using a Er:YAG laser would be effective and safe in cutting dentin for clinical application.

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