• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.341-344
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• 1993

This paper presents the general MRAC algorithm design, it's real time implementation and investigates the effect of purely deterministic disturbances to adaptive control algorithm. The design of adaptive control algorithm to reject the disturbances properly is also presented. In real time application, adaptive control algorithm is considered to investigate its performance by using DC motor. Disturbance rejection algorithm is investigated in simulation.

• Journal of applied mathematics & informatics
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• v.41 no.1
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• pp.155-165
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• 2023

We consider circular Rayleigh problem of hydrodynamic stability which deals with linear stability of axial flows of an incompressible iniviscid homogeneous fluid to axisymmetric disturbances. For this problem, we obtained two parabolic instability regions which intersect with Batchelor and Gill semi-circle under some condition. This has been illustrated with examples. Also, we derived upper bound for the amplification factor.

• Journal of Oral Medicine and Pain
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• v.45 no.1
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• pp.1-11
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• 2020

Purpose: The purpose of this study was to assess influences of psychological factors on sleep disturbances in young adults through the revised version of the Minnesota Multiphasic Personality Inventory (MMPI-2). Methods: Two hundred and ninety nine college students in Gyeonggi-do completed the MMPI-2 and a questionnaire related to sleep disturbances and collected data were analyzed by logistic regression. Results: The odds of tooth grinding increased significantly with the increase of T-score of hysteria (Hy) scale. The increase of T-score of hypomania (Ma) and social introversion (Si) scale significantly contributed to the risk of insomnia. The occurrence of insomnia increased significantly as T-score of somatic complaints (RC1) and psychoticism (PSYC) scale increased. The odds of tooth grinding increased significantly as T-score of anxiety (ANX) and family problems (FAM) scale increased. The occurrence of insomnia decreased significantly with the increase of T-score of type A behavior (TPA) scale. The increase of T-score of dominance (Do) scale significantly contributed to the risk of tooth clenching. The odds of tooth grinding decreased significantly as T-score of MacAndrew alcoholism-revised (MAC-R) scale increased, whereas it increased significantly as T-score of addiction potential scale (APS) increased. No scale of MMPI-2 significantly affected the occurrence of snoring. Conclusions: T-scores of Hy, ANX, FAM, Do, MAC-R, and APS scales on MMPI-2 affected the risk of bruxism. T-scores of Ma, Si, RC1, PSYC, and TPA scales on MMPI-2 influenced the occurrence of insomnia. The psychometric instrument such as MMPI-2 is helpful in understanding and managing bruxism and insomnia.

• Journal of Chest Surgery
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• v.19 no.2
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• pp.232-237
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• 1986

The intraventricular conduction disturbances have been documented after correction of ventricular septal defects by any surgical route but debated its etiology. And so the frequency of conduction disturbances following right ventriculotomy, right atriotomy and pulmonary arteriotomy for closure of ventricular septal defects was compared in various conditions. The present series consists of 218 patients with ventricular septal defects. They had the surgical repair at the Seoul National University Hospital from January 1983 to October 1984. Conduction disturbances were studied with conventional 12 leads electrocardiogram. Of the 218 VSD`s 139 patients were repaired via vertical right ventriculotomy, 45 patients via right atriotomy, 34 patients via pulmonary arteriotomy. 1] Of 218 patients the frequency of RBBB was 26.1% and the frequency of RBBB + LAH was 6.0%. 2] There is no statistical difference between right ventriculotomy group [30.2%] and right atriotomy group [24.4%]. But there is significant difference between right ventriculotomy group and pulmonary arteriotomy group [11.8%] [P<0.05]. 3] In respect to anatomical classification by Kirklin`s method, the frequency of RBBB was higher in type II [32.1%] than in type I [14.9%]. [P<0.05] But in each anatomical type, there is no influence of the various surgical approach on the incidence of postoperative RBBB. 4] The frequency of RBBB was 31.8% in patch closure group and 14.3% in direct closure group. [P<0.05] Although the result suggests that there is no significant difference in various surgical approaches on the incidence of postoperative conduction disturbances, it may be reduced by a new-ventricular approach or a limited incision at right ventricular outflow tract in right ventricular approach.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.222-229
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• 2016

Active synthetic aperture sonar on the small UUV is generated several trajectory disturbances under the influences of underwater environments, and causing a large error in the synthetic aperture processing. In this paper, we analyzed the effects of azimuth resolution for the phase mismatch of the synthetic aperture focus processing when the periodic or random trajectory disturbances was generated on the side direction. The simulation results show that ghost targets are generated and azimuth resolution is very deteriorated when disturbance amplitude is greater than $0.3{\lambda}$ and disturbance period is greater than $2L_{sa}$ in the periodic trajectory disturbances environments. And detection performance on the seabed small objects by the synthetic aperture processing is shown that there is a significant effects on the azimuth resolution depending on the types and conditions of the platform trajectory disturbance variations.

• Journal of Oral Medicine and Pain
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• v.40 no.3
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• pp.102-109
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• 2015

Purpose: The purpose of this study was to assess the association between sleep disturbances and personality type. Methods: Five hundred twenty-four college students in Gyeonggi-do completed the Myers-Briggs Type Indicator (MBTI) and a questionnaire and collected data were analyzed by SAS 9.4 program. Results: Extroversion (E) type, sensation (S) type, and perceiving (P) type had significantly higher prevalence of insomnia than introversion (I) type (p<0.05), intuition (N) type (p<0.05), and judging (J) type (p<0.001), respectively. Tooth grinding, snoring and insomnia appeared to occur more frequently in feeling (F) type than in thinking (T) type. Tooth clenching, tooth grinding and snoring seemed to occur more frequently in S type than in N type. Insomnia occurred significantly the most frequently in sensation-feeling (SF) type (p<0.05). Tooth grinding and snoring seemed to occur the most frequently in SF type. A significantly increased percentage of sensation-perceiving (SP) type demonstrated insomnia (p<0.001). Tooth clenching, tooth grinding and snoring seemed to occur the most frequently in sensation-judging (SJ) type. Sensitive or nervous type of personality had significantly higher prevalence of insomnia than relaxed or general type of personality (p<0.01). A significantly increased percentage of subjects with bad general health status showed insomnia (p<0.0001). Tooth clenching and snoring seemed to occur the most frequently in subjects with bad general health status. A significantly decreased percentage of normal weight subjects demonstrated tooth grinding (p<0.05). Snoring occurred significantly the most frequently in overweight subjects (p<0.001). Tooth clenching showed significant correlation with stress (p<0.01) and personality (p<0.05). Snoring showed significant correlation with stress (p<0.05) and body weight (p<0.001). Insomnia showed significant correlation with stress (p<0.0001), personality (p<0.01), and general health status (p<0.0001). Conclusions: Sleep disturbances including tooth clenching and insomnia were associated with personality type and it is desirable to manage them considering personality type.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.215-222
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• 2017

An active synthetic aperture sonar mounted on small UUV is generated various trajectory disturbances in the traveling path by the influence of external underwater environments. That is the phase mismatch occurs in the synthetic aperture processing of the signals reflected from seabed objects and fetches the detection performance decreases. In this paper, we compensated deteriorated images by the active SAS autofocus processing using DPC and analyzed the effects of detection performance when the periodic trajectory disturbances occur in the side direction at a constant velocity and straight movement of UUV. Through simulations, the deteriorated images according to the periodic disturbance magnitudes and period variations in the platform were compensated using difference phases processing of the overlapping displaced phase centers on the adjacent transmitted ping signals, and we conformed the improved performance characteristics of azimuth resolution and detection images at 3dB reference point.

• Journal of Forest and Environmental Science
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• v.34 no.5
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• pp.359-375
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• 2018

The long term ecological effects have been reported in natural forest ecosystem due to various anthropogenic disturbances, especially in tropics of the world. The present study was carried out in the sanctuary area of central India to assess the changes on litter biomass, litterfall pattern and soil attributes under different disturbance regimes. The study area includes three forest circles i.e., Bhoramdeo, Jamunpani and Salehwara each comprising three disturbances regimes viz., high, medium and low severity of biotic pressure. A noticeable variation and impact were recorded in different sites. The impact varies significantly from least disturbed sites to highly disturbed sites across the circle and among different disturbances level. The seasonal mean total forest floor biomass across the forest circles varied from 2.18 to $3.30t\;ha^{-1}$. It was found highest under lightly disturbed site and lowest under heavily disturbed site. Total litterfall varied from 5.11 to $7.06t\;ha^{-1}\;yr^{-1}$ across the forest circle. Lowest litterfall was recorded at heavily disturbed site while highest in lightly disturbed site. Annual turnover of litter varied from 69-73% and the turnover time ranged between 1.37-1.45 years. The turn over time was higher for heavily disturbed site and lower for lightly disturbed site. The heavily disturbed site of all the circle showed the sandy loam soil texture, whereas moderately and lightly disturbed site comprised of sandy loam, sandy clay loam and clay soil texture, respectively. The bulk density decreases from heavily disturbed site to lightly disturbed site and the pH of soils ranged from 5.57-6.89 across the circle. Across the circle the total soil nitrogen ranged from 0.12-0.21%, phosphorus from 10.03-24.00 kg and Potassium from $139.88-448.35kg\;ha^{-1}$, respectively. Our results demonstrate that anthropogenic disturbances regime significantly influences forest floors in terms of mass, composition and dynamics along with litterfall rate and soil properties.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.448-456
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• 2011

Introduction: Condylar fractures are common in the maxillofacial region, comprising 29-40 percent of all mandibular fractures, accounting for about 20-62 percent). Previous studies reported that pediatric condylar fractures can cause disorders in facial growth and function, and the treatment methods have been controversial. Recently, conservative treatment has shown good results in skeletal growth and functional recovery but the conservative treatment of pediatric condylar fractures has shown unpredictable and undesirable results in some cases, such as facial asymmetry and temporomandibular joint disorder. This study examined the specific age groups and specific mandibular condylar fracture type in growing children treated conservatively in the past. Materials and Methods: Eighteen patients (10 men and 8 women) who received conservative treatment for unilateral condylar fractures in Dankook University Dental Hospital between 2000 to 2007 were followed up for a mean period of 7.2 years. Results: In the survey of 18 pediatric patients who received conservative treatment for condylar fractures, the incidence of temporomandibular dysfunction and growth disturbance was 45% and 35%, respectively. Conclusion: In all complications, the symptoms observed most frequently was mouth opening displacement of the mandible exceeding 2 mm. The other complications of functional and growth disturbance included facial asymmetry concentrated along specific condylar types. Complications including facial asymmetry and functional and growth disturbances showed an increasing tendency according to the specific fracture types. Functional and growth disturbances in the undisplaced condylar fracture type showed a lower incidence(P <0.05). Functional and growth disturbances differed according to the fracture type, which has poor relationship with articular fossa and condyle(P <0.05). Functional and growth disturbance in the cases of the high-level condylar fracture type showed a higher incidence(P <0.05). The functional and growth disturbances of the fracture types were similar in the fragment-contact and non-contact groups(P >0.05).