• 구강회복응용과학지
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• 제19권4호
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• pp.257-268
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• 2003

The purpose of this study was to assess the loading distributing characteristics of implant prosthesis according to position and direction of load, under vertical and inclined loading using FEA analysis. The finite element model was designed according to standard fixture (4.1mm restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction (loading condition B), 200N at the centric usp in a $15^{\circ}$ inward oblique direction (loading condition C), 200N at the in a $30^{\circ}$ inward oblique direction (loading condition D) or 200N at the centric cusp in a $30^{\circ}$ outward oblique direction (loading condition E) individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study: 1. Stresses were concentrated mainly at the ridge crest around implant in both vertical and oblique loading but stresses in the cancellous bone were low in both vertical and oblique loading. 2. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading than with the vertical loading. 3. An offset of the vertical occlusal force in the buccolingual direction relative to the implant axis gave rise to increased bending of the implant. 4. The relative positions of the resultant line of force from occlusal contact and the center of rotation seems to be more important. 5. The magnitude of the stress in the supporting bone, fixture and abutment screw was greater with the outward oblique loading than with the inward oblique loading and was the greatest under loading at the centric cusp in a $30^{\circ}$ outward oblique direction. Conclusively, this study provides evidence that bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. But it seems to be more important that how long is the distance from center of rotation of the implant itself to the resultant line of force from occlusal contact(leverage). The goal of improving implants should be to avoid bending of the implant.

• Wind and Structures
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• 제15권6호
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• pp.531-553
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• 2012

Many tall buildings possess through-building gaps at middle levels of the building elevation. Some of these floors are used as sky gardens, or refuge floors, through which wind can flow with limited blockage. It has been reported in the literature that through-building gaps can be effective in reducing across-wind excitation of tall buildings. This paper systematically examines the effectiveness of two configurations of a through-building gap, at the mid-height of a tall building, in reducing the wind-induced dynamic responses of the building. The two configurations differ in the pattern of through-building opening on the gap floor, one with opening through the central portion of the floor and the other with opening on the perimeter of the floor around a central core. Wind forces and moments on the building models were measured with a high-frequency force balance from which dynamic building responses were computed. The results show that both configurations of a through-building gap are effective in reducing the across-wind excitation with the one with opening around the perimeter of the floor being significantly more effective. Wind pressures were measured on the building faces with electronic pressure scanners to help understand the generation of wind excitation loading. The data suggest that the through-building gap reduces the fluctuating across-wind forces through a disturbance of the coherence and phase-alignment of vortex excitation.

• 한국전자파학회논문지
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• 제15권6호
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• pp.579-589
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• 2004

일반적인 시간 영역에서의 레이더 신호들은 표적의 관측각에 민감하게 변화한다. 이로 인하여 각도가 넓어짐에 따라서 표적 구분의 정확도가 상당히 감소하게 된다. 이러한 문제를 해결하기 위하여 본 논문에서는 다중각도 정보를 이용하여 표적 구분 성능을 향상시키기 위한 방법을 제시한다. 먼저, 대표적인 시간영역 레이더신호인 1차원 range profile로부터 central moments와 PCA를 결합하여 특성백터를 추출한다. 추출된 특성백터에 다중 각도 정보를 사용하는 구분기를 적용시켜 넓은 관측각에서 표적 인식 성능을 향상시킬 수 있다. 다중 각도정보를 이용하는 기법에는 독립방식과 종속방식이 있으며, 본 논문에서는 두 기법의 성능을 비교한다. 성능 비교 실험에는 포항공대 단축거리 무반향실에서 측정된 여섯 개의 항공기 모델에 대한 레이더가 단면적 데이터가 이용된다.

• 문화기술의 융합
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• 제6권4호
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• pp.31-37
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• 2020

본 연구는 드라마 <절정>(2011)을 통해서 드라마에서 시 텍스트가 삽입되는 방식과 시인의 표상화 방식을 검토한다. 이 드라마는 시인이자 독립 운동가였던 이육사를 중심인물로 내세우고, 그의 생애를 따라가는 서사 구조를 택하고 있다. 드라마는 시인의 생에서 가장 극적인 순간에 그의 시를 환상적인 이미지와 함께 삽입함으로써 드라마의 서정성과 영상미를 극대화한다. 시와 함께 제시되는 이미지는 이육사의 치열한 고난을 극대화하는 한편으로, 시를 이 고난의 결정체로 그려낸다. 이로써 드라마 <절정>은 이육사의 시를 활용함으로써 중심인물 이육사의 내면세계를 영상으로 형상화한다. 이육사의 시를 이미지와 함께 활용하여 시의 아름다움과 곧은 정신세계를 지닌 시인의 표상화를 동시에 꾀하는 것이다. 이는 시인이자 독립 운동가였던 이육사를 행동하는 지식인으로서 균형감 있게 그려낸 결과이다. 드라마 <절정>은 영상을 통하여 시와 시인의 표상화를 진정성 있게 수행한 주요한 텍스트이다.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.400-416
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• 2017

Music emotion is an important component in the field of music information retrieval and computational musicology. This paper proposes an approach for automatic emotion classification, based on rough set (RS) theory. In the proposed approach, four different sets of music features are extracted, representing dynamics, rhythm, spectral, and harmony. From the features, five different statistical parameters are considered as attributes, including up to the $4^{th}$ order central moments of each feature, and covariance components of mutual ones. The large number of attributes is controlled by RS-based approach, in which superfluous features are removed, to obtain indispensable ones. In addition, RS-based approach makes it possible to visualize which attributes play a significant role in the generated rules, and also determine the strength of each rule for classification. The experiments have been performed to find out which audio features and which of the different statistical parameters derived from them are important for emotion classification. Also, the resulting indispensable attributes and the usefulness of covariance components have been discussed. The overall classification accuracy with all statistical parameters has recorded comparatively better than currently existing methods on a pair of datasets.

• Wind and Structures
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• 제6권5호
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• pp.325-346
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• 2003

High-sided road vehicles are susceptible to a sharp-edged crosswind gust, which may cause vehicle accidents such as overturning, excessive sideslip, or exaggerated rotation. This paper thus investigates the dynamic behaviour and possible accidents of high-sided road vehicles entering a sharp-edged crosswind gust with road surface roughness and vehicle suspension included. The high-sided road vehicle is modelled as a combination of several rigid bodies connected by a series of springs and dampers in both vertical and lateral directions. The random roughness of road surface is generated from power spectral density functions for various road conditions. The empirical formulae derived from wind tunnel test results are employed to determine aerodynamic forces and moments acting on the vehicle. After the governing equations of motion are established, an extensive computation work is performed to examine the effects of road surface roughness and vehicle suspension on the dynamic behaviour and vehicle accidents. It is demonstrated that for the high-sided road vehicle and wind forces specified in the computation, the accident vehicle speed of the road vehicle running on the road of average condition is relatively smaller than that running on the road of very good condition for a given crosswind gust. The vehicle suspension system should be taken into consideration, and the accident vehicle speed becomes smaller if the vehicle suspension system has softer springs and lighter dampers.

• 복식
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• 제59권7호
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• pp.1-16
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• 2009

This study is on the children's clothing in Seoul Gyeonggi-do, Chungcheong-do and Gangwon-do between the $1920s{\sim}1950s$, by comparing positive data collected from pictures and literatures, remains and interviews. A baenaet jeogori was made of soft white cotton fabrics and was used as a charm when the baby had grown and had an test or a big occasion. A dureong chima and pungcha trousers were clothes for both boys and girls from their birth to the age of $4{\sim}5$ when they could have bowel movements by themselves. Occasions for celebrating a baby's growth were the one-hundredth day and the first birthday. In general, ordinary families had their babies' one-hundredth day in a simple way without special clothes. On the first birthday, however, even ordinary families prepared new clothes for their babies, and read their fortune and prayed for their well being and long life through events such as doljabi. In the age when medicine was poor and the infant mortality was high, the meaning of such a ceremony was to congratulate on the baby's safe growth through dangerous moments.

• Steel and Composite Structures
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• 제30권3호
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• pp.293-304
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• 2019

The optimum cost of a reinforced concrete plane and space frames have been found by using the Genetic Algorithm (GA) method. The design procedure is subjected to many constraints controlling the designed sections (beams and columns) based on the standard specifications of the American Concrete Institute ACI Code 2011. The design variables have contained the dimensions of designed sections, reinforced steel and topology through the section. It is obtained from a predetermined database containing all the single reinforced design sections for beam and columns subjected to axial load, uniaxial or biaxial moments. The designed optimum beam sections by using GAs have been unified through MATLAB to satisfy axial, flexural, shear and torsion requirements based on the designed code. The frames' functional cost has contained the cost of concrete and reinforcement of steel in addition to the cost of the frames' formwork. The results have found that limiting the dimensions of the frame's beams with the frame's columns have increased the optimum cost of the structure by 2%, declining the re-analysis of the optimum designed structures through GA.

• 대한치과보철학회지
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• 제31권3호
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• pp.394-410
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• 1993

This study was accomplished for appreciation of the mandibular moments according to antero- posterior movement of pivot placed on the lower natural dentition. For this study, 20 subjects(male, $21\sim30$ yrs., average age 24) in the category of normal occlusion were selected, and the intraoral Vitallium clutches were cast and fabricated for each subjects. A 2-dimension PSD(Position Sensitive Detector, Hamamatsu Photonics Co., Japan) was attached to maxillary clutch in a mode of three dimensional control and LED (Light Emit Diode, Hamamatsu Photonics Co., Japan) was set up on mandibular clutch. Both clutches were set into oral cavity of each subjects and adjusted. Then the subjects were allowed to intercuspated with maximal bite force while the pivoting ball in the mid-line moving from anterior toward posterior position. The displacement scales were recorded by CCD camera(Sony, CCD-TR-705) and VCR, The conclusions were as follows : 1. When the subject was allowed to bite the metal pivoting ball in the midline of lower dentition with maximal bite force voluntarily while moving from lower central incisor to canine, 1st premolar, End premolar, 1st molar and 2nd molar. The lever actions on the pivot were revealed in all subjects. The equilibrium of moment were revealed on the pivots of 1st premolar(14 subjects), End premolar(4 subjects), and canine(2 subjects) areas. 2. The changes of loading on the TMJ according to antero-posterior positional changes of metal pivoting ball were able to recognize as follow. Compression on the TMJ was increased when the pivot moves anteriorly from the equilibrium point, and tension on the TMJ was increased when posteriorly. 3. 13 subjects were recognized their habitual chewing sides(Rights, Left8), and 7 subjects were not. During maximal biting, mandible was displaced toward their habitual chewing sides on the metal pivoting ball in the frontal plane. 4. In cephalometric analysis, the average genial angle of 20 subjects was $116.75^{\circ}$ and the average mandibular body length was 79.77mm. The equilibrium points of mandibular moment were positioned more posteriorly in the subjects having larger Genial angle than in the smaller(p<0.05). Relationships among the angle between FH plane and occlusal plane, the angle between occlusal plane and mandibular plane , and mandibular body length were not significant(p>0.05).

• 한국통신학회논문지
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• 제28권12C호
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• pp.1225-1238
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• 2003

본 논문에서는 PDA에 장착된 카메라를 사용하여 획득한 명함 영상에 대한 회전 보정 알고리듬을 제안한다. 제안된 방법은 크게 블록적응 이진화부, 스트라이프 생성부, 회전각 계산부, 그리고 영상 회전부로 구성된다. 블록적응 이진화부에서는 입력 영상의 불균일한 조명이나 그림자의 영향을 감소시키기 위하여 입력 영상을 블록별로 이진화한다. 스트라이프 생성부에서는 인접한 문자와 이들로 이루어진 문자열들을 병합하여 문자열 클러스터를 생성하고, 생성된 클러스터 중에서 회전각 계산에 유용한 것들을 스트라이프로 분류한다. 회전각 계산부에서는 스트라이프들의 방향각을 중심 모멘트를 이용하여 계산하고 이들 방향각을 평균하여 입력 영상의 회전각으로 결정한다. 영상 회전부에서는 입력 영상을 계산된 회전각 만큼 회전시킨다. 실험결과 제안된 방법은 여러 종류의 명함을 다양한 주변 여건에서 PDA로 획득한 시험 영상에 대하여 약 93%의 회전 보정률을 보였다.