• Journal of Oral Medicine and Pain
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• v.22 no.2
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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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• v.28 no.2
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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.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.87-94
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• 2014

It becomes critical to understand an energy coupling mechanism between flow perturbations and combustion heat release rate fluctuations for the understanding of high-frequency combustion instabilities occurring in high-performance combustion/propulsion systems. A significant amount of experimental researches have been carried out to understand flame dynamic characteristics by use of flame transfer functions with artificial flow disturbances. Among them, there exist substantial studies on flame response by the excitation of inlet flow. Recently, experimental studies simulating transversal modes excited in actual combustion systems are under way.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.2
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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.

• Journal of muscle and joint health
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• v.5 no.2
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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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• v.17 no.7
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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.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.419-425
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• 2015

When a train is delayed because of a disturbance, the time interval between successive trains increases and high-frequency metro lines can become unstable. Time interval control is therefore necessary in preventing such instabilities. In this paper, we propose an optimal interval control algorithm that is easy-to-implement and that guarantees system stability. In the proposed method, the controlled trains are determined from the time interval deviations between successive trains; the control algorithm for staying time is designed by use of a discrete traffic model to ensure an optimal time interval between successive trains. The results of a computer simulation are also given to demonstrate the validity of the proposed algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.131-137
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• 2005

The purpose of this paper is to evaluate the axial magnetic flux measurement could be used as a tool of the condition monitoring system for the induction motor and to develope the diagnostic algerian for the electric motors. The magnetic leakage flux signal is captured by the flux coil located at the end of motor without the disturbance of the operation. And the signal is analyzed both time and frequency bases to detect the failure of the motor. Specific signature can be described in time and frequency domain for each faults of the motor. The spectrum of the signal was found more useful for the monitoring purpose. The supply voltage imbalance and tin to turn failure of the stator winding could be detected by analysing the specific sidebands of the axial flux and sideband of the rotor bar pass frequency with the high resolution spectrum. The goal of this study verity that the axial flux measurement for the induction motor is a powerful tool for the diagnostic method and develope the algorithm to detect the fault.

• Korean Journal of Environment and Ecology
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• v.2 no.1
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• pp.50-65
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• 1988

Trail and campground deteriorations and their environmental changes of soil and vegetation were studied in Guryong district of Mt. Chiak National Park in 1988. The Widths of both the entire trail and the bare portion as the trail condition were significantly greater on the more heavily used trail. and regressions showed the significant positive relationship between slope along the trail and maximum depth of the trail($R^2$=0.35). Deterioration types of trail which had higher frequency for a total of 63 observations were rock exposure(48%), trail deepening(29%) and root exposure(27%) in the high order. And occurence of trail deterioration was considerably influenced by slope along the trail Ecological changes of soil and vegetation of trailsides were not found at a uniform tendency but could be grouped, by the types of user's disturbance. On campsites. tree damage types and their frequencies were basic as a means of which grasp the limits of user's impact. The area with damaged trees on campsite in pine forest were larger than that in mixed forest and the frequency by damage type of trees varied according to the distance from the core of campsite and to the crown layer. Water content, pH and hardness of soil. coverage of lower trees, species and individuals per 100$m^2$, basal areas of upper and middle layer of trees had significant relationship with the distance from campsite to forest. The range influenced by user's disturbance was more than 70-80m, md Staphylea bumalda, Morns bombycis, Stephanandra incisa and Securinega suffruticosa were considered as tolerant species to user's impact.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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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.