• The korean journal of orthodontics
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• v.44 no.6
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• pp.304-311
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• 2014

Objective: The purpose of this study was to evaluate the effect of malocclusion or orthodontic treatment on oral health-related quality of life (OHRQoL) in adults. Methods: The sample consisted of 860 adults (378 men and 482 women, aged 18-39 years) who were clinically evaluated for malocclusion or orthodontic treatment experience. Participants were divided into 4 groups as follows: normal occlusion, malocclusion, fixed treatment, and retention. OHRQoL was assessed with the short form of the Oral Health Impact Profile (OHIP-14) and Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ). Results: The malocclusion group and the fixed treatment group had significantly higher OHIP-14 scores than the normal occlusion group and the retention group (p < 0.001). The malocclusion group had the highest PIDAQ score, while the normal occlusion group and the retention group had the lowest PIDAQ score (p < 0.001). Women had higher OHIP-14 and PIDAQ scores than men. A significant positive correlation was found between OHIP-14 and PIDAQ scores (p < 0.01). Conclusions: Malocclusion has a negative impact on OHRQoL, but this could be improved in adults through orthodontic treatment. These OHRQoL questionnaires can provide additional useful information on specific aspects of orthodontic patients' psychological state.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.6
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• pp.591-598
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• 1984

The results of measurements showing normal vibrations and rubbing noise generated during unlubricated smooth sliding between metal surfaces are presented. The measurements were made on pin-on-disc type apparatus instrumented with piezoelectric acceleration transducers and microphones. Spectral analysis of the both signals up to frequency of 10kHz indicates that they are closely correlated. The major components of both signals in this frequency range are primarily associated with the normal contact vibrations which are excited by surface irregularities being swept through the contact region during sliding. As an approximation to the seismic input of surface irregularities, an effective surface wavenumber spectrum was assumed in the form of an inverse vibration and noise measurements for a number of surface finishes and mean loads. The predominant frequency component of which levels of the normal vibration and noise are close to overall levels of the both signals is induced by contact resonance between the two bodies and its frequency can be calculated from the Hertzian theory.

• Journal of the Korean Society of Costume
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• v.14
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• pp.199-208
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• 1990

In order to eximine the body form of the physically handicapped people, the 11 items of angle, 54 items of size and weight of the subjects were measured body silhouetter photographs and with the Martin's anthrophometeric instrument respectively. The subjects were consist of 37 boy students who are 13-19 years old and hemiplegias caused by cerebral palsy. And then the comparison between normal and paralysis sides, analysis of somatotypes with the body silhouetter photographs, ANOVA for effect of somatotype on measuring items for angles, and factor analysis for all items were carried out. The results were as follows: 1. The results of measuring are difference between normal and paralysis sides. 2. The items shown significant differences between normal and paralysis sides are diagonal anterior chest B, scapula length, armscye girth, diagonal posterior chest A, and arc of the bust. 3. The percentage of each somatotype shows the order of bending somatotype, turning over somatotype, turning over-bending somatotype, and standard somatotype in the upper body. There are significant differences between somatotypes and sternalis up, sternalis down, scapula, vertebialis, ${\alpha}$, and ${\beta}$ angles respectively. 4. From the result of factor analysis, front and back sections, length items of the upper part and the lower part from the bust line, and the upper size items at the bottom of armscye were abstracted.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.391-407
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• 1990

This study was performed to establish the cephalometric standards and to observe the nature of anatomic fit in the internal structural relationship of the craniofaciodental complex of the normal Korean by means of Moyers' method. Lateral cephalograms of 143 males and 144 females with normal occlusion and acceptable profile from 6 to 25 years of age, which were consisted of 5 groups that were 6 year-, 9 year-, 12 year-, 15 year- and adult-group were obtained. Data were gathered by traced digitizing the cephalograms and were statistically analyzed. The findings can be summerized as follows. 1. Norms of Korean males, females and both sexes in each group were established. 2. There was little significant sexual dimorphism in the form of craniofacial skeleton of all age groups. 3. The height and length of craniofacial skeleton was alike in each sexes in the 6 year-, 9 year- and 12 year-group, whereas it was larger in male than in female in the 15 year- and adult-group. 4. There were no significant sexual differences in the internal structural relationship of the craniofacial skeleton in all age groups.

• Journal of the Korean Statistical Society
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• v.7 no.1
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• pp.3-10
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• 1978

Let $X_i,...,X_n$ be a random sample from a distribution with cumulants $K_1, K_2,...$. The statistic $t = \frac{\sqrt{x}(\bar{X}-K_1)}{S}$ has the well-known 'student' distribution with $\nu = n-1$ degrees of freedom if the $X_i$ are normally distributed (i.e., $K_i = 0$ for $i \geq 3$). An Edgeworth series expansion for the distribution of t when the $X_i$ are not normally distributed is obtained. The form of this expansion is Prob $(t

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.353-358
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• 2014

Purpose: This study was conducted to evaluate desorption efficiency and storage stability on activated carbon acquired form domestic market. Materials: Mixture of acetone, benzene, normal hexane and toluene was injected on four types of charcoal 100 mg. After overnight, charcoal was desorbed by carbon disulfide $1m{\ell}$ and analyzed by gas chromatography with flame ionization detector. Results: Desorption efficiency of benzene, normal hexane and toluene in charcoal tubes were 95% ~ 105%. But desorption efficiency of acetone in charcoal tubes was below 75% and different from types of charcoal. The more injected amount of acetone on charcoal showed higher desorption efficiency. Acetone injected on charcoal tubes migrated from front section into back section after 10 days storage at room temperature. Conclusions: Desorption efficiency and storage stability of activated carbon acquired from domestic market was good for benzene, normal hexane and toluene. The activated carbon acquired from domestic market has ability to be used as sampling media.

• Wind and Structures
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• v.22 no.6
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• pp.685-701
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• 2016

Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.

• Geomechanics and Engineering
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• v.11 no.5
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• pp.671-690
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• 2016

This work presents a static flexure analysis of laminated composite plates by utilizing a higher order shear deformation theory in which the stretching effect is incorporated. The axial displacement field utilizes sinusoidal function in terms of thickness coordinate to consider the transverse shear deformation influence. The cosine function in thickness coordinate is employed in transverse displacement to introduce the influence of transverse normal strain. The highlight of the present method is that, in addition to incorporating the thickness stretching effect (${\varepsilon}_z{\neq}0$), the displacement field is constructed with only 5 unknowns, as against 6 or more in other higher order shear and normal deformation theory. Governing equations of the present theory are determined by employing the principle of virtual work. The closed-form solutions of simply supported cross-ply and angle-ply laminated composite plates have been obtained using Navier solution. The numerical results of present method are compared with those of the classical plate theory (CPT), first order shear deformation theory (FSDT), higher order shear deformation theory (HSDT) of Reddy, higher order shear and normal deformation theory (HSNDT) and exact three dimensional elasticity theory wherever applicable. The results predicted by present theory are in good agreement with those of higher order shear deformation theory and the elasticity theory. It can be concluded that the proposed method is accurate and simple in solving the static bending response of laminated composite plates.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.143-148
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• 2009

Introduction: To correct abnormal occlusal plane by orthognathic surgery, we need to have clear criteria for therapeutic occlusal plane. Authors introduced the concept of individualized ideal occlusal plane(Y-plane), which is determined by the size and form of the mandible, and the ideal incisor tip considering upper and lower lip. Authors studied the following to verify if the actual occlusal plane of the patients with optimal jaw relationship corresponds with the individualized ideal occlusal plane. Patients: We reviewed 44 patients who have normal occlusion visitied in the Dept. of orthodontics, Pundang CHA hospital. Methods: We evaluated if there are agreement between individualized ideal occlusal plane(Y plane) and occlusal plane of actual patients. And we confirmed if tested group has a normal face by measuring FABA, FMA, AB-LOP. Results: There were no significant differences of FABA, FMA, AB-LOP, Mo-Y plane between male and female. FABA, FMA and AB-LOP were included in the normal value. Average distance of Mo-Y plane was $0.75{\pm}0.78mm$. Conclusion: Individualized ideal occlusal plane may be applied to orthognathic surgery.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.65-78
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• 1988

The development of good arch form, the orientation of the dentition with relation to the craniofacial skeleton and the establishment of correct relationship of axial inclination of upper and lower teeth are required in normal occlusion, but different teeth present different degrees of axial inclination. The purpose of this study was to investigate the axial inclination of upper and lower teeth by analyzing $45^{\circ}$ oblique and $90^{\circ}$ cephalometric roentgenograms of 35 Korean males and 34 females with normal occlusion. The obtained results were as follows: 1. Mean and standard deviation of mesiodistal axial inclination of upper and lower teeth related to palatal plane and occlusal plane were obtained. 2. Mesiodistal axial inclination of upper first premolar was nearly perpendicular to palatal plane, and the axis of lower first premolar was nearly perpendicular to occlusal plane. 3. There was no difference in the mesiodistal axial inclination of anteriorly positioned teeth between the three groups: third molar eruption into good alignment (Group 1), third molar impaction or partial eruption (Group 2), third molar agenesis (Group 3). 4. There were low correlationships only between the axial inclination of central incisor and the mesiodistal axial inclination of canine and first premolar, but no correlationships between central incisor and posterior teeth behind first premolar.