• 제어로봇시스템학회논문지
• /
• 제7권2호
• /
• pp.168-172
• /
• 2001

The accuracy problem of robot manipulators has long been one of the principal concerns in robot design and control. A practical and economical way of enhancing the manipulator accuracy, without affecting its hardware, is kinematic calibration. In this paper an effective and practical method is presented for kinematic calibration of Stewart platforms. In our method differential errors in kinematical parameters are linearly related to differential errors in the platform pose, expressed through the forward kinematics. The algorithm is tested using simulated measurement in which measurement noise is included.

• Industrial Engineering and Management Systems
• /
• 제3권1호
• /
• pp.63-70
• /
• 2004

In this paper, we consider the adjustment of convergence on Color Display Tube (CDT). Convergence is a measure of how well the red, green and blue beams are physically aligned with each other to strike the same area on the screen. When misconvergence (convergence error) occurs, one way of compensating it is to attach several ferrite sheets on the inner part of Deflection Yoke (DY). We suggest an optimization model of misconvergence compensation process and report test results for 81 DY samples. As a result, more than 90% of the samples could be made to satisfy the required convergence criteria.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권1호
• /
• pp.76-81
• /
• 1999

The degree of relative similarity between 2D patterns is obtained using Open-Ball Scheme. Open-Ball Scheme employs a method of transforming the geometrical information on 3D objects or 2D patterns into the features to measure the relative similarity for object(patten) recognition, with invariance on scale, rotation, and translation. The feature of an object is used to obtain the relative similarity and mapped into [0, 1] the interval of real line. For decades, Moment-Invariant Method has been used as one of the excellent methods for pattern classification and object recognition. Open-Ball Scheme uses the geometrical structure of patterns while Moment Invariant Method uses the statistical characteristics. Open-Ball Scheme is compared to Moment Invariant Method with respect to the way that it interprets two-dimensional patten classification, especially the paradigms are compared by the degree of closeness to human's intuitive understanding. Finally the effectiveness of the proposed Open-Ball Scheme is illustrated through simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권9호
• /
• pp.1653-1667
• /
• 2011

Privacy is one of the most important and difficult research issues in ubiquitous computing. It is qualitative rather than quantitative. Privacy preserving mainly relies on policy based rules of the system, and users cannot adjust their privacy disclosure rules dynamically based on their wishes. To make users understand and control their privacy measurement, we present a scheme to quantize the personal privacy. We aim to configure the person's privacy based on the numerical privacy level which can be dynamically adjusted. Instead of using the traditional simple rule engine, we implement this scheme in a complex way. In addition, we design the scenario to explain the implementation of our scheme. To the best of our knowledge, we are the first to assess personal privacy numerically to achieve precision privacy computing. The privacy measurement and disclosure model will be refined in the future work.

• 기술혁신학회지
• /
• 제13권1호
• /
• pp.184-203
• /
• 2010

지금껏 국가연구개발사업의 효율성 평가는 성과물로 도출된 결과치에만 의존함에 따라 사업 고유의 특성을 충분히 반영하지 못하였다. 따라서 본 연구는 사업 고유의 특성이 효율성에도 반영될 수 있는 방안으로 평가위원과 효율성을 연계하는 모형을 탐색하였다. 이를 위해 본 연구는 평가위원의 인식을 검토할 수 있는 AHP 방법과 효율성을 분석할 수 있는 DEA방법을 접목하여 분석하였다. 또한 사례분석을 통해 가중치 적용 이전의 연구결과와 비교 분석함으로써, 평가위원의 가중치가 효율성의 분석에 미치는 영향을 제시하였다. 본 연구는 사업의 효율성을 판단할 때 평가위원의 인식을 고려해야 한다는 점을 제시한 것으로 현행과 같이 평가위원의 참여와 역할이 사업의 평가에 국한되지 아니하고 사업의 효율성 평가에도 확대되어야 함을 보여주고자 하였다.

• 한국항공우주학회지
• /
• 제38권11호
• /
• pp.1136-1143
• /
• 2010

NASA가 발사한 LRO 달 탐사선의 정밀궤도 결정을 위해서 지상에서 발사한 레이저를 이용하여 단방향 거리측정 기술이 적용되었는데, 이는 실제 탐사선의 임무에 활용되는 첫번째 시도라고 할 수 있다. 본 연구에서는 LRO 달 탐사선의 레이저 거리측정을 수행하는 탑재체 및 지상 시스템, 레이저 비행시간 및 망원경 지향 오차 요소들을 분석하였다. 또한, 지상에서 발사한 레이저 펄스가 earth window내에 검출되기 위한 기술들을 분석하였다. 이러한 기술들을 적용하여 실제 LRO 달 탐사선의 레이저 추적을 통해서 관측한 데이터를 분석하고 이를 통해 성공적인 단방향 거리측정 기술이 구현될 수 있음을 확인하였다.

• 한국전자통신학회논문지
• /
• 제13권1호
• /
• pp.113-118
• /
• 2018

본 연구는 K-대학교 학군사관 후보생(ROTC)들의 디지털 리터러시 수준분석을 위해 기존에 개발된 디지털 리터러시 체크리스트를 이용하여 설문을 실시하였다. 응답결과를 바탕으로 수집된 측정결과에 대해 타당성과 신뢰도를 검증하기 위해 통계분석프로그램 SPSS 21.0으로 문항요인분석을 실시하였으며, 연구 대상 집단별로 각 요인별 능력수준을 분석하였다. 빈도분석, T-test와 One-way ANOVA를 사용하여 분석한 결과를 근거로 학군사관 후보생의 디지털 리터러시 수준 향상 방안을 제안하였다.

• 아동학회지
• /
• 제10권1호
• /
• pp.26-42
• /
• 1989

This study was designed to investigate the relation between mother's interaction strategies and self-regulation of young children from a Vygotskian perspective. The hypotheses of this study were: 1) The self-regulation of young children will improve with increase in age, 2) the use of mothers' interaction strategies will increase as child's age decreases, 3) mothers' directiveness in the mother-child interaction depends on the age of child and socio-economic level, and 4) mothers' directiveness in the mother-child interaction will have negative relationship with child's self-regulation. The subjects of this study were 60 mother-child dyads with three different age-of-child groups (3-, 4-, and 5-year-olds). They were further divided into higher and lower socio-economic groups. A puzzle task was used for the measurement of self-regulation. The task consisted of two identical puzzles with one used as the model. The collected data were analyzed by ${\chi}^2$, one-way and two-way analysis of variance, and Pearson's r. Self-regulation of the young children improved with increase in age (P < .05). The use of mothers' interaction strategy decreased as the children's age increased (P < .05). Mothers' directiveness in the mother-child interaction was influenced by the age of child (P < .01) and by socioeconomic level (P < .05). There was a negative correlation (r=-.848) between the mothers' directiveness in the mother-child interaction and the child's self-regulation (P < .001).

• 대한통합의학회지
• /
• 제2권1호
• /
• pp.51-62
• /
• 2014

Purpose : The purpose of this work was to ascertain the effects of cervical traction on the pain, the range of motion and the quality of sleep of the older women with the tension headache. Method : 25 subjects between ages 66 and 82 who agreed on this experiment and diagnosed with tension headache participated in this study. All subjects were treated with air-pressure cervical traction while 20 minutes a day, 3 times per week, for 4 weeks. The effects of air-pressure cervical traction were evaluated by PSQI(Pittsburgh sleep quality index), a pain last a day, VAS, and four ROMs. In order to investigate the effect of age on the treatment, subjects were divided into two groups, of less and of over than age 75. The measured data were analyzed by using one-way repeated ANOVA and two-way repeated ANOVA. Result : 1) The group of less than age 75 showed the significant improvements in all measurement variables, PSQI, a pain last a day, VAS and four ROMs. 2) The group of over than age 75 showed the significant improvements in all measurement variables excluding the flexion ROM of cervical. 3) No significant differences between two groups were showed in all measurement variables, but the interaction effect between group and period was significant in only VAS. Conclusion : From the results of this study, a cervical traction intervention using an air-pressure cervical traction proved to be effective on the reduction of tension headache and the improvement of the quality of sleep.

• 한국콘텐츠학회논문지
• /
• 제21권5호
• /
• pp.996-1003
• /
• 2021

연구의 목적은 치과용 스캐너의 반복측정 안정성 비교를 통해 영향을 미치는 스캐너의 요소를 평가하는 것이다. 연구 목적을 달성하고자 청색광을 사용하는 I사의 스캐너와 광학 방식을 사용하는 Z사의 스캐너 그리고 백색광을 사용하는 D사의 스캐너를 본 연구의 반복측정 안정성 연구에 사용하였다. 측정 결과는 root mean square (RMS)로 계산하였고 one-way ANOVA 통계기법을 적용하여 유의수준을 확인하였다(𝛼=.05). 통계분석 결과 가장 큰 RMS 값을 가지는 스캐너는 Z-opt 그룹으로 38.2 ㎛이었다. 다음으로는 D-white가 35.2 ㎛로 나타났고, 가장 RMS 값이 적은 그룹은 I-blue 그룹으로 34.1 ㎛이었다. 각 그룹간에 RMS 평균을 비교한 결과는 유의하지 않은 것으로 나타났다(p>.05). 이 결과로부터 청색광, 백색광 그리고 광학 방식의 스캐너에서는 반복측정 안정성에서 청색광의 오차가 가장 낮은 것으로 나타났으나 통계적 유의성은 없었다. 연구결과 임상적 허용 가능하다는 것이 본 연구의 결론이다.