• 대한치과교정학회지
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• 제17권1호
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• pp.7-13
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• 1987

This study was conducted to clarify the relationship of hyoid bone position to tongue position and mandible when malocclusion is categorized in the bilateral and in the vertical components. Five groups of samples (normal occlusion, unilateral and bilateral cross-bite, openbite, deep-bite) were selected for his investigation by utilizing the cephalograms. On the basis study, the following conclusions were obtained; 1. In the normal group. the mean hyoid position (H-M) was $9.83{\pm}4.27mm$. The mean distance of hyoid body to tongue dorsum (H-T) was $52.17{\pm}6.70mm$. The ratio of H-M/H-T was $18.59\%$. 2. In all malocclusion groups, the hyoid position (H-M) was found to be larger than that of the norm except the deep overbite group 3. The tongue dorsum position (H-T) was increased, compared to that of norm, in all malocclusion groups. 4. Hyoid position (H-M) was found to show high correlation to the ratio of H-M/H-T, H-T, PI-T (0.890, 0.699, 0.455). 5. The hyoid position (H-M) was found to show low correlation to the measurements of mandible, but among them the ODI was found to show conversely a little higher correlation against hyoid position (H-M).

• 대한한방소아과학회지
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• 제27권3호
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• pp.1-11
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• 2013

Objectives The purpose of this study is to evaluate the characteristics of autonomic nervous system in heart-weakened children via analyzing heart rate variability (HRV) compare to healthy children. Methods Among the children who have visited the department of pediatrics at OO oriental medicine hospital, the subjects were composed of 62 elementary school students without cardiac disorder, who have yet develop secondary sexual characteristics. Results 1. Mean HRT and SDNN of the heart-weakened group of children were lower than the healthy group, but with no statistical significance. 2. Heart-weakened children had higher LF norm and LF/HF ratio, but lower HF norm than healthy children. The rest of the Frequency Domain Index have no significant differences. 3. Heart-weak score showed a positive correlation with Mean HRT and LF/HF ratio. Conclusions Heart-weakened children had an imbalance in autonomic nervous system due to increase of sympathetic nerve activity and decrease of parasympathetic nerve activity.

• 한국항만경제학회지
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• 제18권1호
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• pp.43-60
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• 2002

Apart from the DEA method, the traditional measuring systems of container terminal productivities generally bring to light the partial productive efficiencies, because they evaluate only the productivity of each individual facility. However, these methods do not play roles of the reasonable productivity measures to compare and evaluate the efficiencies of terminals to meet the requirement of terminal customers like as shipping lines, shippers, etc. with the cutthroat competition in container handling market. As the suppliers of service, the terminals struggle to cope with the needs of buyers' markets due to the lack of suitable criteria to measure the efficiencies. Therefore, this paper uses the simulation approach to reveal which strategies enhance the productivities through the container terminal analysis. An additional intent of this paper is to build the active strategies to present what the experimental indexes like as norm-time exactness ratio, norm-time excess ratio, etc. compare between terminals to measure the total productivities for the age of global supply chain management. However, the experimental productivity indexes presented in this paper require a validation of the exact usefulness, by consideration from all angles in the future, and a development to more reasonable measuring method/indexes for the container terminal productivities.

• Korean Journal of Acupuncture
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• 제30권4호
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• pp.305-318
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• 2013

Objectives : The aim of this study was to examine the effect of electroacupuncture(EA) at an acupoint, HT8(Sobu), on normal humans by using power spectral analysis. We examined the effect on the Heart Rate Variability(HRV), and the balance of the autonomic nervous system. Methods : Thirty-two healthy volunteers participated in this study. EEG(Electroencephalogram) power spectrum exhibits site-specific and state-related differences in specific frequency bands. A thirty-two channel EEG study was carried out on thirty-two subjects(14 males; mean age=23.5 years old, 18 females; mean age=21.5 years old). HRV and EEG were simultaneously recorded before and after acupuncture. Results : In the ${\alpha}$(alpha) band, during the HT8-acupoint treatment, the power values in the ${\alpha}$(alpha) band significantly decreased(p<0.05) at 28 channels. In the ${\beta}$(beta) band significantly decreased(p<0.05) at 26 channels. In ${\delta}$(delta) band significantly decreased(p<0.05) at 18 channels. In ${\theta}$(theta) band significantly decreased(p<0.05) at 20 channels. ${\alpha}/{\beta}$ values were increased at 6 channels and decreased at 10 channels.${\beta}/{\theta}$ values were increased at 10 channels and decreased at 19 channels. Mean-RR(RR-interval), Complexity, RMSSD(Root mean square of successive differences), SDSD(Standard deviations differences between adjacent normal R-R intervals), norm HF showed a significantly increased and mean-HRV, norm LF, LHR(LF/HF Ratio) showed a significantly decreased after HT8-acupoint treatment(p<0.05). Conclusions : These results suggest that EA at the HT8 mostly causes significant changes on alpha(28 channels), beta(26 channels), delta(18 channels), theta(20 channels) bands and mean-HRV, mean-RR, complexity, RMSSD, SDSD, norm LF, norm HF and LHR. If practicing EA at the HT8, it will regulate the function of the cerebral cortex, decrease activity of the sympathetic and increase parasympathetic nervous activity.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.371-380
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• 2003

In this paper, a new design method of H$H_\infty$-Qn PSS using genetic algorithm(GA) is proposed to efficiently damp low frequency oscillations despite the uncertainties and various disturbances of power systems. The selection method of evaluation function is proposed for selecting the robust PSS parameters. All QFT boundaries are satisfied automatically and H$H_\infty$-norm is minimized simultaneously without trial and error procedure. The eigenvalues and the damping ratio of dominant oscillation mode are investigated to evaluate performance of designed controller for one machine infinite bus system. A disturbance attenuation performance is investigated through singular value bode diagram of the system. Dynamic characteristics are considered to verify robustness of the proposed PSS by means of nonlinear simulations under various disturbances for various operating conditions. The results show that the proposed PSS is more robust than conventional PSS.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1051-1059
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• 1992

Two types of digital repetitive control systems are analyzed and designed to reduce the error spectrum including not only harmonic but also non-harmonic components. First, a novel gain scheduling algorithm is suggested for conventional and modified repetitive controller is scheduled to reduce the infinite norm of error in frequency domain. For this, the relative error transfer function is mewly defined as the ratio of the error spectrum for the system with a repetitive controller to the error spectrum for the system with a repetitive controller to the error spectrum for the system without a repetitive controller. Secondly, as an alternative of a repetitive control system with the gain scheduling, a repetitive control system with higher order repetitve function is analyzed and designed, where instead of equal weightings, weightings of the higher order repetitive function is determined in such a way that the infinite norm of relative error transfer function is minimized. To show the validities of proposed methods, computer simulation results are illustrated for a typical disk drive head positioning servo system.

• 한국심리학회지ㆍ건강
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• 제14권2호
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• pp.277-292
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• 2009

급성 스트레스 상황에 따른 Type D 성격의 자율신경계 반응을 심박률 변동성을 중심으로 조사하였다. Type DS-14의 점수에 근거하여 Type D 집단(n=23명)과 non-Type D 집단(n=23명)을 구성하였다. 심박률 변동성(heart rate variability, HRV)을 이용하여 기저선, 스트레스 단계 및 회복 단계 동안의 심박활동을 측정하였으며 스트레스 과제로는 Stroop 색채단어 검사가 사용되었다. 반복측정 변랑분석을 통해 두 집단의 심박활동을 비교하였으며, 회귀분석을 통해 Type D 척도와 스트레스 취약성 척도가 기저선 상태에서의 심박활동의 변화를 예측할 수 있는지를 알아보았다. 연구 결과, Type D 집단은 non-Type D 집단보다 고주파수(high frequency, HF) 활성화가 더 낮았고 저주파수(low frequency, LF) 활성화는 더 높았다. 스트레스 과제 수행 시, non-Type D 집단에서는 교감신경계 활성화 지표(LF component, LF/HF)가 증가하고 부교감신경계 활성화 지표(HF component)가 감소하는 것이 관찰된 반면, Type D 집단에서는 심박활동 비율상의 유의한 변화가 나타나지 않았다. 또한, Type D 척도의 총점수, 부정적 정서 소척도와 사회적 억제 소척도는 기저선 상태에서의 심박활동 반응에 대한 유의한 예측인자로 나타났다. 이러한 결과는 Type D 성격이 non-Type D 성격에 비해 교감신경계 활성화 비율이 높거나 또는 부교감신경계 활성화비율이 낮음을 시사한다. 즉, Type D가 스트레스에 취약한 성격임을 시사하며, Type D에서 관찰된 심박 활동 양상, 즉 높은 교감신경계 혹은 낮은 부교감신경계 활성화는 Type D 성격이 심장혈관 장애 등을 포함한 정신신체 질환과 관련될 수 있음을 시사한다.

• Journal of Acupuncture Research
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• 제30권3호
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• pp.39-49
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• 2013

Objectives : The purpose of this study is to assess the effect of Taegeuk acupuncture on reducing mental stress by analyzing heart rate variability in Soeumin. Methods : Six Soeumin-diagnosed men participated in this study. They were randomly divided into group A and group B. Each participant went through 4 sessions every week with 1 week of washout period in between each session. HRV was measured three times at every session; at baseline, after administering mentally stressful circumstances and after applying Soeumin Taegeuk acupuncture or Soyangin Taegeuk acupuncture. This study was designed as a crossover clinical trial. Group A participants were treated with two sets of Soeumin Taegeuk and Soyangin Taegeuk acupuncture treatment in respective order (i.e. Soeumin Taegeuk - Soyangin Taegeuk - Soeumin Taegeuk - Soyangin Taegeuk acupuncture treatment). Group B participants were treated with reverse-ordered acupuncture treatment (i.e. Soyangin Taegeuk - Soeumin Taegeuk - Soyangin Taegeuk - Soeumin Taegeuk acupuncture treatment ). Bayesian analysis was performed by using WinBUGS(Ver. 1.4.3) for comparison between Soeumin Taegeuk acupuncture and Soyangin Taegeuk acupuncture. Results : Overall, Soeumin Taegeuk acupuncture tends to reduce LF/HF ratio, LF, HF, LF(Norm) and increase HF(Norm) more than Soyangin Taegeuk acupuncture, but the difference was not statistically significant. In one participant, however, Soeumin Taegeuk acupuncture reduced LF/HF ratio, LF(Norm) and increased HF(Norm) more than Soyangin Taegeuk acupuncture, and the difference was stastatistically significant. Conclusions : This study suggests that Soeumin Taegeuk acupuncture might be an effective means of stabilizing mental stress-induced imbalance of autonomic nervous system for Soeumin.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.310-319
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• 1995

We represent graphically the relationship of hierachical log linear models by regarding the values of the likelihood ratio statistics as the squared norm of the corresponding vectors. Right angled triangles, tetrahedrons, and modified polyhedrons are used for graphical description. We find that the angle between the two vectors depends on the coefficient of determination and the partial coefficent of determination. Thess graphical descriptions could be applied to the model selection method.

• Journal of Acupuncture Research
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• 제27권3호
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• pp.93-104
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• 2010

Objectives : The purpose of this study is to observe the effects of work environment and low back pain on the structural and muscle strength changes in lumbar spine to helpful for preventation and cure of low back pain. Methods : Through measuring of lumbosacral angle, lumbar lordotic angle, lumbar gravity line ratio analyzed structure of lumbar spine and using Trunk Extension Flexion Program of CYBEX NORM System(cybex770+TMC, USA) analyzed Flex. PT, Ext. PT, E/F ratio of lumbar spine of company employees given a medical examination. Results : According to work environment, lumbar gravity line ratio is higher in white collar group than in blue collar group, Ext. PT is significantly lower in white collar group than in blue collar group. According to low back pain or not, lumbar gravity line ratio, Ext. PT is lower in low back pain group than in non-low back pain group. Conclusions : Work environment and low back pain effects on the structural and muscle strength changes in lumbar spine.