• Journal of Oral Medicine and Pain
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• 제22권2호
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• pp.359-371
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• 1997

Stress is recognized as a major predisposing and/ or precipitating factor in long-lastig intractable chronic pain, such as temporomandibular disorders, headache, and other psychophysiological disorders. So it is necessary to detect physical and psychological changes induced by stress as soon as possible for positive treatment outcome. This study was performed to investigate the occurrence rate of stress symptoms according to anatomic region, type of symptom, and other personal and social factors. 859 subjects from general population answered the stress symptom questionnaire devised by the author and composed of 50 items. Data from the questionnaire were analyzed statistically with SPSS program and the results obtained were as follows : 1. Oral symptom which showed the highest frequency rate of 38.8% was vesicular lesion of the lip and cheek. The other symptoms with more 20% occurrence rate were ulcerative leion of lip and cheek, toothache, paresthesia of teeth, eruption of tongue, tongue coating and taste change in descending order. 2. In extraoral symptoms, ？데 disturbance was the item which showed the highest frequency rate of 62.0%, and the items for stiffness of suboccipital region and neck, headache, facial swelling, furuncle of face were answered more than 45% of the subjects whereas only 14.0% of the subjucts complained jaw pain under stress. 3. The better one who thought his or her health status was, the fewer items were answered and the difference of symptom frequency by dwelling place and by having hobby were shown in extraoral symptoms only. 4. For relief of stress symptoms, 79.2% of the subjects replied only to take a rest whereas not more than 13, 5% of the subjects visited dental clinic. Correlationship between symptom sites were very high.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.382-392
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• 2004

The usage of constant velocity (CV) joint is effective for motorboats on gliding regime of the motion. During transition on the gliding when angle of the CV differs from null on driving and driven composite shafts there are moments of the second order. Excitation of oscillations of the second order moments occurs when driving shafts transmits a variable torque. which generates through CV joint a lateral moment acting on the bearing. As a result of oscillations from a resonating harmonic of a shafting the harmonic with the greater or periodically varying amplitude for power condition trough transferring to nominal power 144kW. Beating conditions coincide with third mode having frequency 45.486 Hz. In that case there is high increasing of the equivalent stresses. The forming of the stiffness of the composite material is concerned to use most orientation of the layer angle in the range of $\pm$60 degrees relatively of shaft axis. Application of that angles for layer orientation gives possibility to avoid high disturbance of the shafting for motorboat transition regime.

• 한국추진공학회지
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• 제18권5호
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• pp.87-94
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• 2014

고성능 연소추진 시스템의 고주파 연소불안정 현상을 이해하기 위해서는 연소 열발생과 유동 섭동간의 에너지 교환 메커니즘 이해가 필수적이다. 화염의 동적 특성 변화를 인위적인 섭동을 통해 화염전달함수로 표현하고 이해하고자 하는 다수의 실험적 연구가 진행되어 왔다. 이 가운데 특히 연소기 입구 유동에 섭동을 가진하여 축 방향 섭동에 대한 화염반응을 살펴보는 연구가 활발히 진행되었다. 최근에는 실제 연소시스템에서 발생하는 횡 방향 음향모드를 모의하는 연구들이 진행되고 있다.

• 한국환경복원기술학회지
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• 제25권2호
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• pp.1-13
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• 2022

The objective of this study is to find out phytosociological characteristics of Quercus acutissima dominant forest in Anseong city. A total of 39 phytosociological relevés were sampled. 4 syntaxa were classified to use the Z.-M. School's methodology. Species compositions in which this study adopted were Oplismenus undulatifolius-Quercus acutissima community(typicum subcommunity, phytolacca americana subcommunity), Quercus acutissima community, Pinus densiflora-Quercus acutissima community. All syntaxa were distributed in a high proportion of synanthropophyte where lower-slopes with low elevations and inclinations. Oplismenus undulatifolius-Quercus acutissima community was mainly distributed in the west side of Anseong city where high intensity and frequency of human impacts was experienced. While in the east where most of the areas are covered mountains, Quercus acutissima community and Pinus densiflora-Quercus acutissima community were distributed. As a results, phytolacca americana subcommunity belong to Oplismenus undulatifolius-Quercus acutissima community is sytaxon that reflects change in species composition of Quercus acutissma dominant forest due to the continuous landuse changes in Anseong city.

• 근관절건강학회지
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• 제5권2호
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• pp.191-205
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• 1998

This study was conducted to identify the relations between the factors influencing syndrome and physical disability of fibromyalgia patients. The subjects of this study were 125 outpatients selected at H. Rheumatism clinic from February to July in 1997, The Collected data were analyzed by Frequency, Pearson correlation using SPSS Windows and Path analysis using LISREL 7.16. The results were as follows. 1. General characteristics of subjects About 2/3 of subjects were over 40years of age and most of them were graduated from high school. The Christian were over a half (54.0%) of subjects. 2. Correlation between Family support, knowledge, Self-efficacy, Syndrome and physical disability. As knowledge was positively related to self-efficacy(r=.306), the family support was positively related to self-efficacy(r=.217), and family support was negatively to syndrome. Self-efficacy showed negative relation with syndrome and Physical disability. Syndrome as physical disability represent positive relation. Therefore all hypotheses were supported. 3. Causal relations between research variables. Family support influenced on syndrome, as syndrome on physical activity, as well as knowledge on self-efficacy & physical disability. The model also showed a good fit to the data[$X^2$=1.21 df=1(p=.546), GFI=.996, AGFI=.971, RMSR=.023]. 4. Correlation between symptoms of Fibromyalyia. Having analyzed the relations between tender point, pain, stiffness, functional disturbance, sleep disturbance, depression, fatigue, anxiety, the results were as follows ; All relations show statistically positive correlation, which means close relationship between symptoms, except between pain and depression, pain and anxiety. As a result, symptoms of Fibromyalgia had close relation. Therefore, these were common, rather than individual symptoms. This syndrome influenced on physical disability, and self-efficacy on the both, as knowledge on self-efficacy. In conclusion, to improve syndrome relief and physical disability of fibromyalgia, nursing interventions such as education, self-efficacy increasing stratagy, and family counseling are needed.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.999-1010
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• 2003

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulators because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electric lines is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H$\_$$\infty$/ framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

• 한국철도학회논문집
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• 제18권5호
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• pp.419-425
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• 2015

도시철도 운행시스템에서 외란에 의해 지연이 발생하면 열차 사이에 간격편차가 발생하고 열차운행 상황이 불안정해진다. 따라서 이러한 불안정한 열차운행을 방지하기 위해서는 열차간격을 적절하게 제어하는 것이 필요하다. 본 논문에서는 상용 도시철도 운행시스템에서 외란에 의해 지연이 발생하는 경우에 안정한 운행을 위하여 간단하면서 효과적으로 적용할 수 있는 열차간격 최적제어 알고리즘을 제안한다. 제안한 알고리즘은 실시간 열차간격 편차의 크기에 따라 제어 대상열차를 결정하고 이산 열차간격 모델을 이용하여 대상열차의 정차시간을 조절함으로써 모든 열차가 적정 운행간격을 유지하도록 제어한다. 또한 시뮬레이션을 통하여 제안한 방법의 유효성을 확인한다.

• 조명전기설비학회논문지
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• 제19권8호
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• pp.131-137
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• 2005

본 논문은 유도 전동기에 대한 상태 모니터링 시스템의 도구로서 축방향 누설자속 측정 방법을 사용할 수 있는가를 평가하고 전동기에 대한 진단 알고리즘을 개발하는 것이다. 결함검출을 위해 전동기를 정지시키지 않고 전동기의 코일단에 설치된 자속코일로 누설자속 신호를 수집하여 전동기의 각종 결함을 검출하기 위해 시간과 주파수영역으로 신호를 분석한다. 전동기 각각의 결함에 대해 시간과 주파수 영역에서 특정 신호 현상이 검출되었다. 전원전압 불평형과 고정자 권선의 선간 단락은 축방향에서 측정된 고해상도의 누설자속 스펙트럼으로부터 특정 측대파와 회전자봉 통과주파수의 측대파를 분석함으로서 결함을 검출할 수 있다. 주파수 영역에서의 스펙트럼이 모니터링 목적으로 더욱 유용하다는 결론을 얻었다. 본 논문에서는 유도 전동기의 축방향 누설자속 측정이 진단 방법으로서 적합한 도구임을 증명하고 결함을 검출하기 위한 알고리즘을 개발하였다.

• 한국환경생태학회지
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• 제2권1호
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• pp.50-65
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• 1988

치악산국립공원의 구룡사지구를 대상으로 등산로 및 야영장의 훼손실태와 그 주변토양 및 식생환경의 변화를 조사하였다. 등산로의 상태를 표현하는 등산로 폭 및 나지노출폭은 이용밀도에 따른 차이가 인정되었으며. 최대깊이는 등산로물매와 직선회귀관계($R^2$=0.35)가 성립되었다. 전구간에 걸쳐 출현빈도가 높은 등산로 훼손형태는 암석노출 (48%). 종침식(29%), 및 뿌리노출(27%) 등의 순이었으며 등산로물매가 훼손발생에 많은 영향을 미치는 것으로 나타났다. 등산로 주변토양 및 식생인자의 변화경향은 일정하지 않았으나 이용객의 간섭형태에 따라 변화경향을 구분할 수 있었다. 야영장에서의 수목훼손형태 및 출현빈도는 이용객의 영향범위의 판단에 유의한 기준이었으며 소나무림야영장이 혼효림야영장보다 훼손범위가 넓었고, 훼손형태별 출현빈도는 거리 및 수관층위에 따라 달랐다. 토양함수량, 토양산도, 토양경도. 하층수관의 피복도, 100$m^2$당 출현수종수, 개체수, 상층 및 중층의 흉고단면적 등의 인자는 야영장에서 임내방향으로 거리가 멀어짐에 따라 유의한 회귀관계를 보였으며, 야영장에서의 이용간섭의 영향범위는 70~80m이상이었다. 야영행위에 대한 내성수종으로는 고추나무, 산뽕나무, 국수나무, 광대싸리 등이 파악되었다.

• International Journal of Aeronautical and Space Sciences
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• 제6권2호
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• pp.23-32
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• 2005

An experimental control system is proposed for the attitude control of a simplified 2-DOF helicopter model. The main rotor is a rigid one, and the fuselage is simply supported by a fixed hinge point where the longitudinal motion is decoupled from the lateral one since the translations and the rolling rotation are completely removed. The yaw trim of the helicopter is performed with a tail rotor, by which the azimuthal attitude can be adjusted on the rotatable post in the yaw direction. The robust sliding mode control tracking a given attitude angle is proposed based on the flight dynamics. A pitch damper is inserted for the control of pitching angle while the compensator to reaction torque is used for the control of azimuth angle. Several parameters of the system are selected through experiments. The results shows that the proposed control method effectively counteracts nonlinear perturbations such as main rotor disturbance, undesirable chattering, and high frequency dynamics.