• 제목/요약/키워드: Post-Current

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Aboriginal Community Archives in Australia and Current Meaning of "Parallel Provenance" (호주 원주민 공동체 아카이브와 '평행출처주의'의 현재적 의미)

  • Lee, Kyong Rae
    • The Korean Journal of Archival Studies
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    • no.40
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    • pp.29-60
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    • 2014
  • The purpose of this study is to trace the formation process of "parallel provenance" concept in the context of Australia's aboriginal community archives development and draw its implications for contemporary rebuilding of domestic "past affairs-related committee archives". Focused on historical development of aboriginal community archives in Australia, this writing divides its development into three periods: colonial archives, post-colonial archives, and contemporary archives and investigates each period's distinct features in managing and building of aboriginal community archives. First of all, for colonial archives, it pays attention to Australia's archival tradition, which focused on current record-keeping and then development of multiple provenance resulted from this tradition. Second, for post-colonial archives, it examines the appearance of aboriginal people as the subject of documentation category and name indexing on them. Finally, for contemporary archives, it analyzes current activities of Australia's academic world of archival science for overcoming "the otherness" of aboriginal people through conceptualization of "parallel provenance". Conclusively, through current meaning of parallel provenance, this study draws implications for democratic contemporary rebuilding of domestic past affairs-related committee archives, in which historical victims become the subject of archives.

Controller Design and By-Pass Structure for the Two-Stage Grid-Connected Photovoltaic Power Conditioning System

  • Lee, Seong-Jun;Bae, Hyun-Su;Cho, B.H.
    • Proceedings of the KIPE Conference
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    • 2009.11a
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    • pp.206-208
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    • 2009
  • In this paper, a systematical controller design method for a twostage grid-connected photovoltaic power conditioning system is proposed. For a pre-stage boost converter to achieve the stable operation in the entire region of solar array, the digital resistive current mode controller is used. This algorithm is very simple to implement with a digital controller and there is no power stage parameter dependency in the controller design. For a post-stage single-phase full-bridge inverter, a PI controller with a feedforward compensation for the inner current control is employed. Furthermore, in case that the operating point of the solar array under varying environmental conditions is higher than the required voltage for the inverter current control, the bypass mode for the boost converter is possible for the more efficient operation. The proposed control scheme is validated through the experiment of the prototype two-stage power conditioning system hardware with a 200W solar array.

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Analysis of Ionization Phenomena in Soils under Impulse Voltages (임펄스전압에 의한 토양이온화 현상의 분석)

  • Park, Geon-Hun;Kim, Hoe-Gu;Choi, Jong-Hyuk;Yang, Soon-Man;Lee, Bok-Hee
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.05a
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    • pp.305-308
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    • 2008
  • This paper presents characteristics of soil ionization when high currents such as lightning and switching surge currents are injected into a grounding rod. Soil ionization phenomena are investigated by using both voltage and current signals recorded by oscilloscope. As a result, a critical electric field intensity($E_C$) for ionization is decreased with reduction of grain size. The pre-ionization resistance($R_1$) and post-ionization resistance($R_2$) at the sand with fine grain size are getting lower with increasing current magnitude. Finally, the time to ionization($t_1$) and ionization current peak($t_2$) of fine grain size are significantly shorter than those of medium grain size.

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The Effects of a Career Group Counseling Program on the Career Maturity and Achievement Motivation of Elementary School Underachievers (진로집단상담 프로그램이 초등학교 학습부진아동의 진로성숙과 성취동기에 미치는 효과)

  • Park, Eun-Jin
    • The Korean Journal of Elementary Counseling
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    • v.6 no.1
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    • pp.49-71
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    • 2007
  • The purpose of this study was to examine the effects of a career group counseling program on the career maturity and achievement motivation of elementary school underachievers. This study targeted the fifth grader underachievers. Twenty underachievers, whose pre-test homogeneity in career maturity and achievement motivation was verified, were allocated to an experimental group and a control group by 10 underachievers each. The program was conducted for a total of 12 sessions, twice per week, and each session lasted 80 minutes. For verification of the program effects in this study, MANOVA and ANOVA were carried out for pre- and post-score tests between the groups, and repeated-MANOVA and paired t-test were peformed to look into the changes within a group by using SPSS/WIN(version 12.0) in terms of statistical analyses. The findings in this study are as follows: First, as a result of post test for the experimental and control groups, and difference verification of post and pre-tests within the experimental group, both career maturity and sub-factors of career maturity demonstrated significant differences. Second, as a result of difference verification of the pre- and post-tests within the experimental group, achievement motivation significantly improved, but there was no statistically significant difference in achievement motivation in the post-test of experimental and control groups. However, of the sub-factors of the achievement motivation, self-confidence and Interest in the long-term future significantly improved. Third, we can see that the career group counseling program provided opportunities for the underachievers to search their own character, interest, and aptitude, and broadly encounter the world of occupations. Also, we can infer that the underachieves had active and developmental attitudes towards future dreams and their current efforts. As noted above, the career group counseling program proved that it has a positive effect to the improvement of the elementary school underachievers' career maturity and achievement motivation in some variables.

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Zero-Current Switching LLC Resonant Post-Regulator for Independent Multi-Output (독립된 다중출력을 위한 영전류 스위칭 LLC 공진형 Post-Regulator)

  • Cho, Sang-Ho;Shin, Yong-Saeng;Yoon, Jong-Kyu;Han, Sang-Kyoo;Roh, Chung-Wook;Hong, Sung-Soo;Kim, Jong-Hae;Lee, Hyo-Bum
    • Proceedings of the KIPE Conference
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    • 2008.06a
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    • pp.481-483
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    • 2008
  • 본 논문은 다양한 종류의 전원을 구비해야 하는 다중출력 전원 시스템을 위한 영전류 스위칭 LLC 공진형 Post-regulator를 제안한다. 기존의 LLC 공진형 컨버터는 정밀한 다중 출력을 얻기 위해 추가의 DC/DC 컨버터가 구성되었고, 이는 전력 변환 효율 감소 및 제조 원가 상승의 단점을 갖고 있다. 제안된 컨버터는 각 소자의 내압 및 전류 스트레스가 작고, 요구되는 출력 당 1 개의 보조 스위치만으로 구현되므로 저가격화에 유리하다. 또한 전력이 전달되는 시점의 공진 전류의 초기값을 가변함으로서 정밀하게 제어되는 다중 출력 전압을 획득할 수 있고, 각 전압의 출력 순서 제어도 가능한 장점이 있다. 뿐만 아니라, 독립된 공진탱크를 이용하기 때문에 공진탱크 설계가 용이하며, 최근 전자 제품의 추세인 슬림화의 요구에 부응할 수 있다. 또한, 제안된 Post-regulator의 모든 전력 스위치는 ZCS가 가능하므로 스위칭 손실을 최소화 할 수 있다. 최종적으로 본 논문에서 제안한 영전류 스위칭 LLC 공진형 Post-regulator를 제작하고, 고찰된 실험결과를 제시하여 제안된 컨버터 및 전원시스템의 우수성과 이론적 분석의 타당성을 검증한다.

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Comparison of oxygen saturation, heart rate of cerebral palsy and normal child between the pre-ambulation and post-ambulation (뇌성마비아동과 정상아동의 보행전후 산소포화도 및 심박수 비교에 관한 연구)

  • Hwang, Joo-Moon;Lee, Wan-Hee
    • Journal of Korean Physical Therapy Science
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    • v.10 no.1
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    • pp.38-46
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    • 2003
  • Since the current tendencies show us the increasing number of cerebral palsy children and the standard longevity, we need to find out more research about the following various problems. Therefore I have tried to figure out the difference of oxygen saturation and heart rate between before ambulation and after. Objects chosen are 17 C.P children on the process of treatment those who were able to walk and 8 normal children in Ah-San hospital, Gang-Nung. They haven't had either any operation or suffered heart disease and I measured their oxygen saturation and heart rate by using pulse-oximeter and are analyzed by SPSS (10.07 version). Results are the followings; 1. There was no difference of oxygen saturation and heart rate between pre-ambulation and post-ambulation of normal and spastic hemiplegia children. 2. There showed the significant statistic difference of oxygen saturation, heart rate between pre-ambulates and post-ambulation of normal and spastic diplegia(p<.05). 3. There was no difference of oxygen saturation, heart rate in C.P between(p>.05), but shows the significant statistic difference in heart rate(p<.05). As I compared the oxygen saturation and heart rate of spastic and normal children on between pre-ambulation and post-ambulation, theres is significant statistic difference on both items (p<.05). However there was no difference of oxygen saturation among hemiplegia, normal and diplegia children while the pulse rate showed the significant difference(p<.05). According to this clinical research, CP children's oxygen saturation and heart rate had no change between pre and post compared to normal children. But there was difference in diplegia. This is why we need to invest time to study these kinds of research about various analysis and comparison of oxygen saturation and heart rate, and furthermore making use of pulse-oxymetry in physical therapy room for the children involved would be beneficial to calculate in accuracy without any discomfort for the patient as well.

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KINEMATIC OSCILLATIONS OF POST-CME BLOBS DETECTED BY K-COR ON 2017 SEPTEMBER 10

  • Lee, Jae-Ok;Cho, Kyung-Suk;Nakariakov, Valery M.;Lee, Harim;Kim, Rok-Soon;Jang, Soojeong;Yang, Heesu;Kim, Sujin;Kim, Yeon-Han
    • Journal of The Korean Astronomical Society
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    • v.54 no.2
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    • pp.61-70
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    • 2021
  • We investigate 20 post-coronal mass ejection (CME) blobs formed in the post-CME current sheet (CS) that were observed by K-Cor on 2017 September 10. By visual inspection of the trajectories and projected speed variations of each blob, we find that all blobs except one show irregular "zigzag" trajectories resembling transverse oscillatory motions along the CS, and have at least one oscillatory pattern in their instantaneous radial speeds. Their oscillation periods are ranging from 30 to 91 s and their speed amplitudes from 128 to 902 km s-1. Among 19 blobs, 10 blobs have experienced at least two cycles of radial speed oscillations with different speed amplitudes and periods, while 9 blobs undergo one oscillation cycle. To examine whether or not the apparent speed oscillations can be explained by vortex shedding, we estimate the quantitative parameter of vortex shedding, the Strouhal number, by using the observed lateral widths, linear speeds, and oscillation periods of the blobs. We then compare our estimates with theoretical and experimental results from MHD simulations and fluid dynamic experiments. We find that the observed Strouhal numbers range from 0.2 to 2.1, consistent with those (0.15-3.0) from fluid dynamic experiments of bluff spheres, while they are higher than those (0.15-0.25) from MHD simulations of cylindrical shapes. We thus find that blobs formed in a post-CME CS undergo kinematic oscillations caused by fluid dynamic vortex shedding. The vortex shedding is driven by the interaction of the outward-moving blob having a bluff spherical shape with the background plasma in the post-CME CS.

Experimental study on the behavior of reinforced concrete beam boosted by a post-tensioned concrete layer

  • Mirzaee, Alireza;Torabi, Ashkan;Totonchi, Arash
    • Computers and Concrete
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    • v.28 no.6
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    • pp.549-557
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    • 2021
  • Nowadays, strengthening of buildings is an inclusive and effective field in civil engineering that is not only applicable to the buildings but also it can be developed for the bridges. Rehabilitation and strengthening of structures are highly recommended for the existing structures due to the alter in codes and provisions as well as buildings' use change. Extensive surveys have been conducted in this field in the world that propose wide variety of methods for strengthening of structures. In recent years, more specific researches have been carried out that present novel materials for rehabilitation beside proposing methods and performing techniques. In the current study, a novel technique for developing the bending capacity of reinforced concrete beams to enhance their performance as well as rehabilitating and reforming the performance of reinforced concrete beams with nonstandard lap splices, has been proposed. In this method, a post-tensioned concrete layer is added to the side face of the concrete beams built in 1:1 scale. Results reveals that addition of the post-tensioned layer enhances the beams' performance and covers their weaknesses. In this method, 18 reinforced concrete beams were prepared for the bending test which were subjected to the four-point pushover test after they were reinforced. The testing process ended when the samples reached complete failure status. Results show that the performance and flexural capacity of reinforced beams without lap splice is improved 22.7% compared to the samples without the post-tensioned layer, while it is enhanced up to at least 80% compared to the reinforced beams with nonstandard lap splice. Furthermore, the location of plastic hinges formation was transformed from the beam's mid-span to the 1/3 of span's end and the beam's cracking pattern was significantly improved.

Experimental calibration of forward and inverse neural networks for rotary type magnetorheological damper

  • Bhowmik, Subrata;Weber, Felix;Hogsberg, Jan
    • Structural Engineering and Mechanics
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    • v.46 no.5
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    • pp.673-693
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    • 2013
  • This paper presents a systematic design and training procedure for the feed-forward back-propagation neural network (NN) modeling of both forward and inverse behavior of a rotary magnetorheological (MR) damper based on experimental data. For the forward damper model, with damper force as output, an optimization procedure demonstrates accurate training of the NN architecture with only current and velocity as input states. For the inverse damper model, with current as output, the absolute value of velocity and force are used as input states to avoid negative current spikes when tracking a desired damper force. The forward and inverse damper models are trained and validated experimentally, combining a limited number of harmonic displacement records, and constant and half-sinusoidal current records. In general the validation shows accurate results for both forward and inverse damper models, where the observed modeling errors for the inverse model can be related to knocking effects in the measured force due to the bearing plays between hydraulic piston and MR damper rod. Finally, the validated models are used to emulate pure viscous damping. Comparison of numerical and experimental results demonstrates good agreement in the post-yield region of the MR damper, while the main error of the inverse NN occurs in the pre-yield region where the inverse NN overestimates the current to track the desired viscous force.

A Clinical Observation on Neurometor Electric Current Charge After Guibitang Administration (귀비탕(歸脾湯) 복용전후(服用前後)의 양도락전류량(良導絡電流量) 변화(變化)에 관(關)한 임상적(臨床的) 고찰(考察))

  • Han, Gyu-Eon
    • Journal of The Association for Neo Medicine
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    • v.1 no.1
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    • pp.115-122
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    • 1996
  • A clinical observation was done on 98 cases performed neurometer diagnosis before Guibitang administration first, and rechecked neurometer diagnosis after Guibitang administration for 10 days. Electric current post administration was compared with ant administration. The following result were obtained. 1. A peak incidence was observed in 30-39 age group. 37 cases(37.8%) were in 30-39 age group. The ratio of male to female was 1:31.7. 2. Chief complaints were fatigue, menoxenia, indigestion, anorexia, constipation, headache, palpitation, insomnia etc. 3. The common result of neurometer point checking was that patients who had the pecularity of low electric current were much than patients who had the pecularity of high electric current. 4. By neurometer diagnosis a peak incidence was observed in gallbladder. Increment was also highest in gallbladder. Gallbladder has a function of psychomotility in oriental physiology. ?5. After Guibitang administration the increment of neurometer electric current was comparatively high in kidney, stomach, small intestine meridian. According to the above menthioned results I consider that Guibitang has the curative effects along the meridian selectively. and increases in function or preserves health within physycal limit.

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