• Title/Summary/Keyword: 무자기

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Attitude Estimation of Unmanned Vehicles Using Unscented Kalman Filter (무향 칼만 필터를 이용한 무인 운송체의 자세 추정)

  • Song, Gyeong-Sub;Ko, Nak-Yong;Choi, Hyun-Seung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.1
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    • pp.265-274
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    • 2019
  • The paper describes an application of unscented Kalman filter(UKF) for attitude estimation of an unmanned vehicle(UV), which is equipped with a low-cost attitude heading reference system (AHRS). The roll, pitch and yaw required at the correction stage of the UKF are calculated from the measurements of acceleration and geomagnetic field. The roll and pitch are attributed to the measurement of acceleration, while yaw is calculated from the geomagnetic field measurement. Since the measurement of geomagnetic field is vulnerable to distortion by hard-iron and soft-iron effects, the calculated yaw has more uncertainty than the calculated roll and pitch. To reduce the uncertainty of geomagnetic field measurement, the proposed method estimates bias in the geomagnetic field measurement and compensates for the bias for more accurate calculation of yaw. The proposed method is verified through navigation experiments of a UV in a test pool. The results show that the proposed method yields more accurate attitude estimation; thus, it results more accurate location estimation.

The Effect of Self-Efficacy and Ego-resilience on College Adaptation after Military Service (군복무 후 제대한 복학생의 진로결정자기효능감과 자아탄력성이 대학생활적응에 미치는 영향)

  • Kim, Hyoun-Mi
    • Journal of Digital Convergence
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    • v.15 no.6
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    • pp.513-523
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    • 2017
  • The purpose of this study is to examine how career decision-making self-efficacy and ego-resilience of college students after military service influence college life adjustment. For this purpose, the questionnaire was administered to 234 male college students who returned to the four-year university in Jeonbuk area. The collected data were analyzed by correlation analysis and hierarchical regression using SPSS 18.0. As a result of examining the correlation between each variables, the subscale adaptation of college life adjustment and university environment adaptation showed a positive correlation with the goal selection of career decision self-efficacy and optimistic attitude of ego-resilience. Future plan of career decision-making self-efficacy, optimistic attitude of ego-resilience and personal-emotional adaptation of college life adaptation showed a positive correlation between self-evaluation of career decision self-efficacy and self-resilience confidence. As a result of hierarchical regression analysis, it was found that ego-resilience had more influence on college life adjustment than career decision self-efficacy. The limitations of this study were discussed along with the significance of this study, which was revealed through data collection only for students who came back after military service.

The Unconscious Desire and the Conflict between Mother and Daughter -A Convergence In-depth Psychological Analysis of the Film, 'DAUGHTER'- (모녀의 무의식적 욕망과 갈등 -영화 '다우더'의 융복합 심층심리학적 분석-)

  • Lee, Chang-Don;Lee, Hyun-Sim
    • Journal of Digital Convergence
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    • v.14 no.2
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    • pp.437-447
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    • 2016
  • This study is intended to analyze the conflict between the mother and the daughter revealed in the film, 'Daughter' and tries to suggest the therapeutic counseling techniques in the integrated perspective. It used a convergence in-depth psychological method. After deriving the unconscious conflicts of main characters through several film reviews, it was found that at the unconscious level true self and the false self, the ego ideal and the super ego, the individuation and the dependency are in mutual struggle. For Therapeutic counselling, the most important thing in the initial stage of the counselling is the experience of authenticity. The counsellor himself or herself should establish the right life values and stimulate the ego-ideal and strengthen the drive of true self. Also the counsellor should be aware of the dangers of the religious behavior as the transitional phenomenon. In the final stage, the counselor expects the client to continue to make efforts to change with the hope for the well-being.

A Study on the Interevent Time Definition(IETD) depending on the Population of Rainfall Data in Busan Metropolitan City (부산광역시 강우자료의 모집단 구분에 따른 무강우 지속시간(IETD) 분석 연구)

  • Baek, Jongseok;Cho, Hyoseob;Kim, Hyungsan;Kim, Jaemoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.416-416
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    • 2022
  • RCP(Representative concentrate pathways) 기후변화 시나리오에서는 2100년까지 연강 강수량과 강우지속시간이 지속적으로 증가할 것으로 예측하고 있다. 이에 도시지역의 하천 범람 및 내수 침수 예방을 위해 방재성늑목표의 상향조정과 방재 인프라의 설계년수 재조정 등에 대한 논의가 진행되고 있다. 하지만 수재해 예방을 위한 강우설계기준에서는 무강우 지속시간의 설정을 확보할 수 있는 최대 규모의 모집단을 통해 산정하는 방식으로 제시되고 있어 최근 기후변화로 인한 강우특성의 변화가 반영되기에 어려움이 있다. 본 연구에서는 부산광역시 강우자료의 모집단을 10년, 20년, 30년으로 구분하여 자기상관계수(Autocorrelation coefficient, AC) 분석, 변동계수(Coefficient of variation, CV) 분석, 연평균 강우사상 발생 개수(Average annual number of rainfall event, NRE) 분석 방법을 적용하여 비교 분석을 수행하였다. 그 결과, 자기상관계수 분석 방법과 변동계수 분석 방법에서는 모집단의 규모가 클수록 튀는 자료를 상쇄하여 안정적인 결과를 나타내는 반면, 연평균 강우사상 발생 개수를 확인 하였을 때는 대상기간에 큰 영향을 받지 않는 것으로 확인되었다. 또한, 모집단의 규모가 클수록 무강우 지속시간이 길어지는 것으로 분석되어 기후변화로 인한 최근의 강우특성을 반영하기 위해서는 모집단의 규모를 크게 잡는 것이 효과적이지 않을 수 있다는 점을 확인하였다. 이는 강우자료 분석 시 분석방법 및 모집단의 규모를 달리하여 무강우 지속시간을 산정해보고, 설계 목적에 따라 적정한 의사결정이 필요함을 시사한다.

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Aging Characteristic on the Magnetic Properties of Non-oriented Silicon Steel (무방향성 규소강판에서 열화특성이 자기적 성질에 미치는 영향)

  • Kim, Hyung-Wook;Kim, In-Sung;Jeong, Soon-Jong;Min, Bok-Gi;Song, Jea-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.242-242
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    • 2007
  • 무방향성 규소강판을 lamination core 형태로 제작하여 자기적 특성을 조사 하였다. 그 결과 1차, 2차 권선수가 400turns 시료에서 보자력(Hc)과 포화자속밀도(Bs)는 최대값을 나타내었고, 보자력은 0.05Oe, 포화자속밀도는 1.8T 이었다. 현재 국내에서 생산되고 있는 무방향성 규소강판의 자속밀도값 보다 더 우수한 강을 나타내었으며, 열화특성이 자기적 특성에 미치는 영향을 통해 고효율 무방항성 규소강판 개발의 가능성을 확인하였다.

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Verification of Stereotactic Target Point Achieved by Acquisition of MR Image in Actual Treatment Position of Radiosurgery (정위적 방사선 수술시 치료위치에서의 정위적 표적점 확인을 통한 자기공명영상 획득의 정확도 연구)

  • 윤형근;신교철;김영식
    • Progress in Medical Physics
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    • v.9 no.2
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    • pp.89-94
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    • 1998
  • To make practical application of the MR image for stereotactic radiosurgery, the target point-achieved by acquisition of MR image in stereotactic radiosurgery planning system must agree with the actual isocenter of irradiation in real treatment. And the amount of distortion of the MR image must be known to make a correction for the agreement. A radish containing abundant water content was chosen as a homogeneous phantom for the purpose of verification of the agreement in this experiment. A dosimetric film was firmly attached to the small specially fabricated acryl plate and needle puncture was made through the film just into the acryl plate and a drop of oil was dropped into the hole of the film. The acryl plate with film was inserted into the radish and the dorp of oil represented the target point in MR image. After the image acquisition by stereotatic radiosurgery planning system, we achieved stereotactic coordinate of the target point represented by the oil drop. And we proceeded to actual irradiation to the target point according to the procedure of stereotactic radiosurgery. After the irradiation, the film in the radish was developed and processed and the degree of coincidence between the center of the radiation distribution and the target point represented by the hole in the film was measured. The discrepancy between two points was under 0.5 mm. so we could confirm good coincidence in homogeneous phantom such as radish. On the other hand, authors tried to use our home-made device for estimation of distortion of MR image.

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YBCO 고온 초전도체의 자기 부상력 및 에너지 저장응용

  • 김찬중
    • Superconductivity and Cryogenics
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    • v.1 no.2
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    • pp.38-48
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    • 1999
  • 용융공정으로 제조한 YBCO 고온 초전도체는 임계전류밀도가 높기 때문에 외부자장을 강력하게 반발한다. 영구자석과 YBCO 초전도체간의 부상력을 이용하면 무접촉으로 회전할 수 있는 베어링을 제작할 수 있다 고온 초전도체 무접촉 베어링은 고에너지 효율의 플라이휠 에너지 저장장치에 활용된다. 초전도 베어링은 전자석을 이용한 자기 베어링에 비해, 위치 제어 시스템 없이 중량물을 공중에 띄워 회전시킬 수 있는 장점이 있다. 플라이휠 에너지 저장장치는 무공해의 환경 친화적인 기술로, 용량과 규모, 에너지 입출력 양과 시간을 조절하기 쉽다. 또한, 장소설정에 제한이 없으므로 에너지를 필요로 하는 장소에 자유롭게 설치할 수 있고, 에너지밀도가 다른 저장시스템에 비해 상대적으로 높다. 현재 선진 각국에서는 에너지의 효율적 저장 및 활용을 위해 고온 초전도체 베어링을 이용한 플라이휠 에너지 저장장치를 국가적 중점 사업으로 개발 중이며 2000년 초에 실용화될 전망이다. 본 논문에서는 고온 초전도체의 자기 부상력, 플라이흴 에너지 저장장치의 개념설계 및 개발동향에 대해 요약하였다.

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