• Title/Summary/Keyword: 자기 이상

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A Design of Node Power Management Monitoring System for Self-sustianability (자기유지지원을 위한 노드 전원 관리 모니터링 시스템 설계)

  • Lee, Sang-Sin;Ryu, Min-Woo;Song, Min-Hwan;Ahn, Il-Yeup;Won, Kwan-Ho;Cho, Kuk-Hyun
    • Proceedings of the KAIS Fall Conference
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    • 2011.12b
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    • pp.697-700
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    • 2011
  • 무선센서네트워크 (WSN, Wireless Sensor Network) 시스템의 활용분야가 다양해짐에 따라 기존 WSN의 문제점을 개선하기 위한 연구가 활발히 이루어지고 있으며, 한정된 배터리 자원 문제는 반드시 해결해야하는 주요한 과제이다. 이러한 문제점을 해결하기 위하여 원격에서 무선 전송 기술을 통하여 에너지를 전송하는 자기유지 지원 기술이 주목받고 있다. 자기유지 지원 기술은 센서 노드의 배터리 교체 및 에너지가 열악한 환경에서 동작 가능한 에너지를 전송하는 기술로서 건물상태 모니터링, 전장 감시 등과 같은 다양한 분야에서 활용되고 있다. 이러한 자기유지 지원 기술은 WSN을 구성하는 센서 노드들 전원 상태를 확인하는 것이 매우 중요하며, 이에 따라 에너지를 공급해야 한다. 따라서 본 논문에서는 자기유지지원을 위한 노드 전원 관리 모니터링 시스템을 설계 한다.

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Z-Score를 이용한 관류영상과 조영전후 감산에 의한 역동영상의 뇌관류 양상의 비교 관찰

  • 최순섭;오종영;남경진;이영일
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.171-171
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    • 2001
  • 목적: 뇌 자기공명영상에서 Z-score를 이용한 관류 영상과 조영전후의 감산에 의한 역동 영상의 관류 양상을 비교 관찰 하고자 한다. 대상 및 방법: 뇌 자기공명영상에서 이상 소견이 없는 젊은 환자 1명, Moya moya 환자 1, 중대뇌동맥 폐색 환자 1명, 외상후 증후군 1명, 뇌종양 1예를 대상으로 하여, 뇌의 routine 자기공명 영상과 함께 Gd-DTPA 0.1 mmol/kg를 급속 주사 후 자화율 대조 EPI 영상을 얻었다. 영상 기기는 Magnetom Vision(Siemens Medical Systems, Erlangen, Germany)이며, EPI 영상 지표들은 TR/TE는 0.8/29 msec, slice 두께 6 mm, slice 수 10, 화소수 128 $\times$ 128, FOV 215 $\times$ 215 mm, 영상획득 1 회, 1회 검사시간 1.32 초, 검사수 30 회로서, 총 검사시간은 40 초였다. 검사 후 영상처리(post processing)는 Magnetom Vision의 VB31D 자체 프로그램을 이용하였는데, 2-score를 이용한 관류영상은 조영제 유입전 영상들, 조영제 최대 유입기 영상들, 그리고 조영제 배출기 영상들 4-5 회를 각각 한 군으로 하여, Z-score 1.2에서 2.0 사이에서 여러번 반복하여 영상을 재구성하였다. 감산에 의한 역동영상은 조영제 도달 전의 영상으로부터 조영제 유입 후의 영상을 차례로 빼어서 영상을 재구성하였으며, 이들 영상을 재정리하여 각 단면의 시간 경과에 따른 관류 양상을 연속하여 관찰하였다 두 방법에 의한 영상 재구성은 각각 약 10분 정도가 소요되었다.

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초음파 진동소자용 Fe-Co-Ge계 합금 복합체의 자기변형 특성 및 WC 첨가 효과

  • 윤용운;유광현;김상우;나석민
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.243-246
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    • 2003
  • 평균 입도가 $100{\mu}m$$Fe_{36}Co_{62}Ge_2$ 합금 분말과 $10wt\%$의 페놀계 고분자 바인더, 그리고 평균 입도가 $1.36{\mu}m$인 WC 분말을 SPEX Mixer/Mill에 넣고 8시간동안 혼합한 후 $150^{\circ}C$에서 Warm press를 이용하여 0.9 ton 의 압력으로 2시간 동안 유지하였다. VSM을 사용하여 자기적 특성을 조사한 결과 WC의 첨가량이 증가할수록 포화자화값(Ms)는 $174\~128\;emu/g$로 감소하였다. 또한 스트레인게이지를 이용하여 자기변형을 측정하였다. WC의 분포를 알아보기 위해 전자현미경으로 복합체의 단면을 관찰하였다. WC의 함량이 $10\~30wt\%$로 증가할수록 밀도와 영률(Young's Modulus) 값이 각각 $5.15\~6.27\;g/cc,\;43.5\~93.6\;GPa$ 로 증가하였다. 특히 영률은 WC를 $30wt\%$로 첨가하였을 때의 값이 첨가하지 않았을 때보다 2배 이상 증가하였다. 그러나 비자성상의 첨가로 희석효과가 나타났으며 길이 방향으로의 자기변형값$(\lambda_{ll})$$d_{33}$의 경우 각각 $18\%$$20\%$ 정도가 감소되었다. 이러한 기계적 특성의 향상은 길이 10mm의 자기변형 복합체의 공진 주파수를 71 kHz 증가시키게 되며, 따라서 초음파 진동소자용으로서의 상업적 활용범위를 증가 가능성을 제시하였다.

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Faraday Rotation of the Hoya FR5 and FR4 Glasses at Cryogenic Temperature (저온에서 Hoya FR5 및 FR4 유리의 Faraday 회전)

  • 이현곤;원영희;이경수
    • Korean Journal of Optics and Photonics
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    • v.6 no.4
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    • pp.352-358
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    • 1995
  • Measurements of the Faraday rotation and magnetization of terbium-doped Hoya FR5 glass and cerium-doped Hoya FR4 glass have been made as a function of temperature T in the range 4.2 K -10 K and of magnetic field H of up to 80 kG at the $Ar^+$ laser wavelength of 514.5nm. The saturations of magnetization and Faraday rotation above H/T> $5kG.K^{-1}$ can be analyzed by the quantum theory of paramagnetism. Calculated parameters show that the large Verdet constant of $Ce^{3+}$ glass is due to the effective $4f\rightarrow5d$ electric dipole transition effect and that of $Tb^{3+}$ glass is due to the magnetization effect.effect.

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Structural, Optical, and Magnetic Properties of Si1-xMnxTe1.5 Single Crystals (Si1-xMnxTe1.5 단결정의 구조적, 광학적, 자기적 특성에 관한 연구)

  • Hwang, Young-Hun;Um, Young-Ho;Cho, Sung-Lae
    • Journal of the Korean Magnetics Society
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    • v.16 no.3
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    • pp.178-181
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    • 2006
  • We have investigated the Mn concentration-dependent structural, optical, magnetic properties in IV-VI diluted magnetic semiconductor $Si_{1-x}Mn_xTe_{1.5} $ crystals prepared by the vertical Bridgman technique. X-ray studies showed the single crystalline hexagonal crystal structure. From the optical absorption measurements energy band gap were found to decreases with increasing x and temperature. From the magnetization measurements the samples had ferromagnetic ordering with Curie temperature $T_C$ about 80 K. With increasing Mn concentration, the average magnetic moments per Mn atom determined from the saturated magnetization increased.

The Effects of Character Education Program based on Self-reflection Using a Liberal-arts Course at University (대학 교양강좌를 이용한 자기성찰 기반 인성교육 프로그램의 효과)

  • Kim, Eunjin
    • The Journal of the Korea Contents Association
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    • v.22 no.2
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    • pp.294-304
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    • 2022
  • The purpose of this study is to examine the effects of a character education program based on self-reflection using a liberal arts course at university. To this end, a single treatment group pre- and post-design was conducted in which data were collected at the beginning and end of the semester for 18 students. For statistical estimation suitable for a small sample size, a non-parametric test was performed to examine the significant mean changes of the data. This program was found to significantly improve the level of self-compassion, life satisfaction, and mental well-being of university students. Based on the above results, it was discussed that the liberal arts course for character education based on self-reflection could be useful as a character education for university students, and the implications and suggestions of the results of this study were presented.

Effects of self-management on psychological happiness in throwers (투척선수들의 자기관리가 심리적 행복감에 미치는 영향)

  • Lee, Myung-Sun;Lee, Moon-Sook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.3
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    • pp.1128-1135
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    • 2011
  • The purpose of this study was to identify the effects of field athletes' self-management on their psychological happiness. The subjects of the study were 184 athletes (male=82, female=102) who participated in the 91th National Athletes Meeting. All statistical analyses and description methods were computed by SPSS window 18.0. The discriminant analysis was used to find effects of self-management on their psychological happiness, ANOVA and Multiple regression. The results of this study were as followings: Frist, there was not significant difference to The Relationship between social-demographical variables and self-management, their psychological happiness. Second, self-management had a significant effect on psychological happiness. Based on the results, Field athletes's self-management has a positive effect on their psychological happiness.

Implementation and Performance Evaluation of Self-Similar Traffic Generator Using OPNET (OPNET을 이용한 자기유사성 트래픽 발생기 설계 및 성능 평가)

  • Han Kyeong-Eun;Jung Kwang-Bon;Lee Seung-Hyun;Kim Young-Chon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.5A
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    • pp.441-450
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    • 2006
  • Recently, with the exponential growth of the number of Internet users, IP traffic which occupies more than 90 percent of the entire Internet traffic affects significantly to the performance of networks. Therefore, the design of the self-similar traffic generator reflected the feature of IP traffic is very important to design the networks efficiently and evaluate the performance of it correctly. In this paper, we design the self-similar traffic generator using OPNET. In order to implement the self-similar characteristics, ON-OFF sources with Pateto distribution are employed and aggregated. The designed self-similarity traffic generator is evaluated and verified with R/S plot, variance time(VT) plot under the various offered loads and the number of sources. It is expected that the designed self-similar traffic generator can be put to practical use when wire or wireless networks is designed and verified as well as it can be useful to decide the specific parameter value for Internet traffic modeling.

Fatigue and Self efficacy on Clinical Practice of Nursing Students (간호학생의 임상실습에 대한 피로와 자기효능감)

  • Kim, Eun-Hee;Suh, Soon-Rim
    • The Journal of the Korea Contents Association
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    • v.14 no.3
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    • pp.328-336
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    • 2014
  • The purpose of this study was to identify levels of fatigue and self-efficacy of clinical practice among nursing students and to examine the relationship of fatigue and self-efficacy. A cross-sectional descriptive study was conducted with 207 senior nursing students. Self-administered questionnaires were used to collect data during the period from 1st to 30th of June, 2013. Data were analyzed by descriptive statistics, t-test, ANOVA, and Pearson's correlation coefficient using SPSS 18.0 program. At the results, the average levels of fatigue and self-efficacy were 3.52/5($SD={\pm}.52$) and 3.29/5($SD={\pm}.47$) respectively that meant above moderate. Study participants having motive of admission to nursing school voluntarily and having high satisfaction with nursing major were shown higher self-efficacy. There were correlated negatively between fatigue and self-efficacy(r=-.315, p<.001). By the findings of this study, it is necessary to develop a nursing practice education program to reduce the level of fatigue and improve the self efficacy of nursing students.