• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1855-1866
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• 2003

This paper discusses an entire procedure for a robust controller design and its implementation of an AMB (active magnetic bearing) spindle, which is part II of the papers presenting details of system modeling and robust control of an AMB spindle. Since there are various uncertainties in an AMB system and reliability is the most important factor for applications, robust control naturally gains attentions in this field. However, tight evaluations of various uncertainties based on experimental data and appropriate performance weightings for an AMB spindle are still ongoing research topics. In addition, there are few publications on experimental justification of a designed robust controller. In this paper, uncertainties for the AMB spindle are classified and described based on the measurement and identification results of part I, and an appropriate performance weighting scheme for the AMB spindle is developed. Then, a robust control is designed through the mixed ${\mu}$ synthesis based on the validated accurate nominal model of part I, and the robust controller is reduced considering its closed loop performance. The reduced robust controller is implemented and confirmed with measurements of closed-loop responses. The AMB spindle is operated up to 57,600 rpm and performance of the designed controller is compared with a benchmark PID controller through experiments. Experiments show that the robust controller offers higher stiffness and more efficient control of rigid modes than the benchmark PID controller.

• 한국자동차공학회논문집
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• 제2권6호
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• pp.29-37
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• 1994

Active noise control of random noise which propatate in the vehicle cabin as a form of spherical wave is the target of this study. In the previous study, the adaptive algorithm for adaptive controller is presented for the application in active noise control system. And for the preliminary study of adaptive active noise control in vehicle cabin as a real system, a computer simulation is performed on the effectiveness of the adaptive algorithm in the amplitude of the pressure fluctuation. This work studies the implementation of multi-channel feedforward adaptive algorithm for the reduction of the noise inside a vehicle cabin using a number of secondary sources derived by adaptive filtering of reference noise source. Multi-channel adaptive feedforward algorithm are verified in numerical simulation and semi-experimental justification of developed system is made on a domestic passenger car. In the results of semi-experimental study, the noise of specific region in the interior of automobile are reduced for the appreciabe sound pressure level in the operating engine rpm and finally this study suggests the capabilities of the real time active noise control in 3 dimensional acoustic fields.

• Structural Engineering and Mechanics
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• 제44권6호
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• pp.775-799
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• 2012

This work approaches the structural performance of masonry arches that have a small ratio between number of vossoirs and span length. The aim of this research is to compare and validate three different methods of analysis (funicular limit analysis F.L.A., kinematic limit analysis K.L.A. and plane stress Finite Element Analysis F.E.A.) with an experimental campaign. 18 failure tests with arches of different shapes and boundary conditions have been performed. The basic failure mechanism was the formation of enough hinges in the geometry. Nevertheless, in few cases, sliding between vossoirs also played a relevant influence. Moreover, few arches didn't reach the collapse. The FLA and KLA didn't find a solution close to the experimental values for some of the tests. The low number of vossoirs and joints become a drawback for an agreement between kinematic mechanism, equilibrium of forces and geometry constraints. FLA finds a lower bound whereas KLA finds an upper bound of the ultimate load of the arch. FEA is the most reliable and robust method and it can reproduce most of the mechanism and ultimate loads. However, special care is required in the definition of boundary conditions for FEA analysis. Scientific justification of the more suitability of numerical methods in front of classic methods at calculating arches with a few vossoirs is the main original contribution of the paper.

• International Journal of Human Ecology
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• 제14권1호
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• pp.57-69
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• 2013

This study investigates Korean high school student's perception of sexual harassment and relative effects of victim's clothing, dating behavior and respondent's gender on perceptions of alleged sexual harassment cases. A quasi-experimental method was applied using a $2{\times}2{\times}2$ between-subjects factorial design that manipulated three variables (clothing exposure, dating behavior, and gender). Questionnaires were distributed to a convenience sample of 540 high school students and 530 questionnaires were used for the data analysis. The results indicate that the victim's clothing and dating behavior had a significant main effect on the responsibility for sexual harassment. The respondent put less responsibility on the assailant when the victim wore revealing clothing and when her dating behavior was provocative. The significant interaction effect between the respondents' gender and the victim's dating behavior indicated that when the victim's behavior was provocative, female respondents held more responsible to victim than male respondents did. The results also indicate that victim's clothing, dating behavior, and respondent's gender had significant main effect on the justification of sexual harassment. The respondents indicated that assailant's behavior is unjustifiable; however, when victim more revealing clothing, they indicated that the behavior is more justifiable.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.29-35
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• 2007

This study was designed to investigate the feasibility to utilize the electromyogram (EMG) for estimating the muscle torque. The muscle torque estimation plays an important role in functional electrical stimulation because electrical stimulation causes muscles to fatigue much faster than voluntary contraction, and the stimulation intensity should then be modified to keep the muscle torque within the desired range. We employed the neural network method which was trained using the major EMG parameters and the corresponding knee extensor torque measured and extracted during isometric contractions. The experimental results suggested that (1) our neural network algorithm and protocol was feasible to be adopted in a real-time feedback control of the stimulation intensity, (2) the training data needed to cover the entire range of the measured value, (3) different amplitudes and frequencies made little difference to the estimation quality, and (4) a single input to the neural network led to a better estimation rather than a combination of two or three. Since this study was done under a limited contraction condition, the results need more experiments under many different contraction conditions, such as during walking, for justification.

• Wind and Structures
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• 제19권6호
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• pp.623-647
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• 2014

In this paper, a probability distribution which is consistent with the observed phenomenon at the roof corner and, also on other portions of the roof, of a low-rise building is proposed. The model is consistent with the choice of probability density function suggested by the statistical thermodynamics of open systems and turbulence modelling in fluid mechanics. After presenting the justification based on physical phenomenon and based on statistical arguments, the fit of alpha-stable distribution for prediction of extreme negative wind pressure coefficients is explored. The predictions are compared with those actually observed during wind tunnel experiments (using wind tunnel experimental data obtained from the aerodynamic database of Tokyo Polytechnic University), and those predicted by using Gumbel minimum and Hermite polynomial model. The predictions are also compared with those estimated using a recently proposed non-parametric model in regions where stability criterion (in skewness-kurtosis space) is satisfied. From the comparisons, it is noted that the proposed model can be used to estimate the extreme peak negative wind pressure coefficients. The model has an advantage that it is consistent with the physical processes proposed in the literature for explaining large fluctuations at the roof corners.

• Applied Biological Chemistry
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• 제20권3호
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• pp.279-284
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• 1977

(가) 검시료수(檢試料數)가 방대하게 되면 관능검사에 장기간을 요하므로 파넬에 미치는 부담감과 권태 피로등의 효과(效果)때문에 실험결과에 오차(誤差)가 크게 발생할 우려가 있다. (나) 다수(多數)의 검시료(檢試料)일 경우 시험수(試驗數)를 축소시키는 반면에 검출력(檢出力)이 양호한 수법(手法)으로써 새로이 표준시험대(標準試驗對) 1대비교법(對比較法)을 고안(考案)적용한 결과 양호(良好)한 성과(成果)를 얻을 수 있었다. (다) 본수법(本手法)은 특(特)히 시료수(試料數)가 많을때 그중에서 $4{\sim}5$개를 우선 선발하는 Screening test로 활용(活用)할 수 있음을 알았다. (라) 본수법(本手法)으로 Screening한 검시료(檢試料)에 대해 3각(角) 1대비교법(對比較法)으로 정사(精査)하여 최종판단을 내리는 일련의 과정을 거치도록 하는 것이 연구실적인 품결연구에 있어서는 가장 능률적인 관능검사의 방법이라고 할수 있다.

• 대한약침학회지
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• 제18권1호
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• pp.7-18
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• 2015

Objectives: Loranthus ferrugineus (L. ferrugineus) from Loranthaceae, a mistletoe, is a medicinal herb used for a variety of human ailments. Traditionally, decoctions of this parasitic shrub have been mainly used to treat high blood pressure (BP) and gastrointestinal complaints; usage which is supported by experimental based pharmacological investigations. Nonetheless, there is still limited data available evaluating this plant's traditions, and few studies have been scientifically translated toward evidence based phytomedicine. We therefore provide a concise review of the currently available L. ferrugineus literature and discuss potential directions for future areas of investigation. Methods: We surveyed available literature covering ethnopharmacological usage of L. ferrugineus and discussed relevant findings, including important future directions and shortcomings for the medicinal values of this parasitic shrub. Results: Evidence based pharmacological approaches significantly covered the medicinal application of L. ferrugineus for hypertension and gastrointestinal complaint management, with a particular focus on the active hydrophilic extract of this herb. Conclusion: Understanding the sites of action of this plant and its beneficial effects will provide justification for its use in old traditional treatments, and potentially lead to the development of therapies. Other medicinal applicative areas of this parasitic shrub, such as wound healing, gerontological effects, and antiviral and anticancer activities, are yet to be researched.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.676-687
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• 2021

본 연구의 주요목적은 붓다볼 명상을 활용하여 중년여성들의 자기 존중감, 긍정적 사고를 향상시키는 프로그램 효과 연구이다. 이러한 연구목적을 달성하기 위하여 본 연구대상은 '붓다볼'에 관심이 있는 부산시 H사찰 중년여성 불자들을 대상으로 하였다. 분석 방법은 본 연구의 단일집단의 사전-사후검사(One Group Pretest-Posttest Design)를 활용하여 실증적 분석을 수행하였다. 주요 연구 결과를 살펴보면, 다음과 같다. 첫째, 붓다볼 명상이 삶의 질에 미치는 효과 검증 결과, 삶의 질 전체는 실험집단에 유의미한 정적(+) 영향을 미치는 것을 살펴 볼 수 있었다. 둘째, 붓다볼 명상이 자기 존중감에 미치는 효과 검증 결과, 자기 존중감은 실험집단에 유의미한 정적(+) 영향을 미치는 것을 살펴 볼 수 있었다. 셋째, 붓다볼 명상이 긍정사고에 미치는 효과 검증 결과, 긍정사고 전체는 실험집단에 유의미한 정적(+) 영향을 미치는 것을 살펴 볼 수 있었다. 이러한 연구결과를 토대로 살펴본, 주요 결론은 소리의 파동 에너지를 활용한 치유 명상의 도구인 붓다볼은 중년여성 불자의 자아존중감, 삶의 질에 긍정적 영향을 미치는 것을 파악할 수 있었다. 이에 따라 붓다볼 명상프로그램은 개인과 가정, 사회적인 환경 여건으로 인하여 더 복합적인 심리적 어려움을 겪는 중년여성들에게 긍정적인 활용 가치가 있음을 판단된다. 아울러 붓다볼 명상프로그램을 교육적·정책적으로 적극적으로 활용할 수 있는 제도를 마련함으로써 중년여성들의 자아존중감, 긍정적 사고 및 삶의 질을 높이는 데 활용할 당위성과 필요성의 시사점을 제시하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.1008-1013
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• 2001

This experiment was conducted to determine the effects of enzyme supplementation on the performance of 80 growing-finishing pigs (26.2 kg) fed diets containing either soybean or canola meal. Barley-based diets formulated using either soybean meal or canola meal were fed with or without enzyme (Allzyme Vegpro, Alltech Biotechnology Centre). Eight castrates and twelve gilts were fed each diet. Digestibility of dry matter, crude protein and gross energy was 8.0 (p=0.0001), 7.9 (p=0.0005) and 7.9 (p=0.0003) percent lower for pigs fed diets containing canola meal compared with soybean meal. Enzyme supplementation had no effect on nutrient digestibility (p>0.05). There was a significant interaction between protein source and enzyme for all three nutrients. Over the entire experimental period (26.2 to 77.9 kg), pigs fed canola meal consumed 9.4% less feed (p=0.001), gained weight 20.4% slower (p=0.001) and had a 12.9% poorer feed conversion (p=0.001) than pigs fed soybean meal. Weight gain, feed intake and feed conversion were unaffected by enzyme addition (p>0.05). Castrates gained weight 11.4% faster (p=0.001), consumed 9.3% more feed (p=0.001) and had a 2.6% better feed conversion (p=0.026) than gilts. There was a significant interaction between protein source and sex of pig for feed conversion. Pigs fed diets based on canola meal had a significantly lower carcass value index (p=0.01), lower lean yield (p=0.007) and lower lean depth over the loin (p=0.001) than pigs fed diets based on soybean meal. Enzyme addition significantly increased lean depth over the loin (p=0.01). There was a significant interaction between protein source and enzyme for carcass value index (p=0.04), estimated lean yield (p=0.05) and fat depth over the loin (p=0.05). These results confirm previous studies which have demonstrated poorer pig performance when canola meal completely replaces soybean meal in diets fed to growing-finishing pigs. In addition, the results provide little justification for the inclusion of the Vegpro enzyme in diets fed to pigs of this weight range.