• 대한치과교정학회지
• /
• 제20권3호
• /
• pp.427-446
• /
• 1990

The objective of this study was to understand the major changes of craniofacial dimensions and spatial growth pattern during the late embryonic and fetal period of human fetures. This study was performed with the selective materials of normal fetuses received from the Registry of Congenital Malformation of Seoul National University Hospital. The specimens consisted of nineteen embryos and sixty-six fetuses. The photomicrographs from mid-segittal sections of embryos were used for angular measurement, and the lateral cephalograms taken with soft X-ray were also measured in liners and angular aspects. All of the anatomical landmarks for the tracing of the photomicrographs and cephalograms were referred to the previous reports on literature. The sequential changes of prenatal craniofacial dimensions and agles were analysed statistically and discussed on the focus about the developmental growth directions of human ore-facial structure arised from heterogeneous origins. The results are as follows, 1) Cranial base angle was almost formed at about 6 weeks old embryos with the average angle of $127.4{\pm}6.33^{\circ}$ (n=3) and it was almost constant onwards. 2) The linear increase rates of anterior cranial base length and anterior facial height exceeded those of the posterior cranial base length and posterior facial height, and the maxilla grows more rapidly on the horizontal dimension than the vertical dmension during the fetal period. 3) The angular relationship between the anterior cranial base and palatal plane decreasedslightly during the fetal period, disclosing $11^{\circ}$ at 12th week gestation and $5^{\circ}$ at 41th weeks gestation. 4) Genial angle was maintained almost constantly at about $130^{\circ}$ during the fetal period from 12 weeks to 41 weeks of gestation.

• 한국항해항만학회지
• /
• 제27권1호
• /
• pp.49-54
• /
• 2003

우리나라가 세계 물류기지의 중심 국으로 발전하기 위해서는 날로 급증하고 있는 물류량을 처리하기 위한 항만의 건성이 시급한 과제이다. 국토가 좁고 대도기에 인구가 급증하고 있으나 삼면이 바라도 둘러 쌓여 잇는 우리나라의 경우에는 해양공간개발이 필요하다. 증가하는 물류량은 처리할 수 있는 항만의 건설을 위하여 본 연구에서는 초대형 부유채식 컨테이너 야드를 제안하고 해상에 설치되는 초대형 부유채식 컨테이너 야드가 파의 길이 , 해역의 수심, 입사하는 파의 방향등에 따라서 어떠한 응답특성을 나타내는지 파악한다.

• Structural Engineering and Mechanics
• /
• 제74권1호
• /
• pp.1-18
• /
• 2020

For the large deformation of shear walls under vertical and horizontal loads, there are difficulties in obtaining accurate simulation results using the response analysis method, even with fine mesh elements. Furthermore, concrete material nonlinearity, stiffness degradation, concrete cracking and crushing, and steel bar damage may occur during the large deformation of reinforced concrete (RC) shear walls. Matrix operations that are involved in nonlinear analysis using the traditional finite-element method (FEM) may also result in flaws, and may thus lead to serious errors. To solve these problems, a planar four-node element was developed based on vector mechanics. Owing to particle-based formulation along the path element, the method does not require repeated constructions of a global stiffness matrix for the nonlinear behavior of the structure. The nonlinear concrete constitutive model and bilinear steel material model are integrated with the developed element, to ensure that large deformation and damage behavior can be addressed. For verification, simulation analyses were performed to obtain experimental results on an RC shear wall subjected to a monotonically increasing lateral load with a constant vertical load. To appropriately evaluate the parameters, investigations were conducted on the loading speed, meshing dimension, and the damping factor, because vector mechanics is based on the equation of motion. The static problem was then verified to obtain a stable solution by employing a balanced equation of motion. Using the parameters obtained, the simulated pushover response, including the bearing capacity, deformation ability, curvature development, and energy dissipation, were found to be in accordance with the experimental observation. This study demonstrated the potential of the developed planar element for simulating the entire process of large deformation and damage behavior in RC shear walls.

• KIEAE Journal
• /
• 제11권2호
• /
• pp.105-111
• /
• 2011

Aims of this study is to investigate the daylighting control strategy of venetian blind system was performed as a function of ratio of shading height to window and slat angles in the preliminary stage of the parametric study. Floor-to-ceiling window walls of living spaces are used widely in apartment buildings since the Korean government has legally allowed elimination of the balcony area. Enlarging living area by balcony elimination, the larger glass area of window is exposed to the direct sunlight. As a common sunlight controlling device, blind system can be used in all orientations and all latitudes and it may obstruct, absorb, reflect and transmit solar radiation to building by proper adjusting. However, blind system can produce discomfort in occupant and less energy efficiency, if it has not been controlled optimally. The simulation model was based on the unit module of typical living space with balcony elimination. The room dimension was $6.0m(w){\times}6.9m(d){\times}2.7m(h)$ with floor to ceiling height of 2.5m. The blind system was simulated at five slat angles (horizontal, $30^{\circ}$, $45^{\circ}$ upward and downward tilted) and the four ratio of shading height to window (fully closed, partly opened, no-blind) using the Desktop RADIANCE 2.0 program. The series of simulation results indicates that the advantages of available daylight and outside of view can be improved by proper adjusting blind system.

• 한국경제지리학회지
• /
• 제12권4호
• /
• pp.454-476
• /
• 2009

본 연구는 부산시 물류창고업의 신뢰형성 수준과 연계의 공간적 특성 간의 관계를 밝히고자 하였으며, 그 결과는 다음과 같다. 첫째, 신뢰형성 요인 중 '장기적 반복적 상호작용', '정보공유와 호혜성', '상호의존과 자산전용성'은 신뢰형성이 높은 수준인 미시적 신뢰, '근접성'과'불확실성'은 중간 수준인 중시적 신뢰, 그리고 '기업의 문화 및 규범과 공식적 제도'는 낮은 수준인 거시적 신뢰에 상대적으로 많은 영향을 미친다. 둘째, 거시적 신뢰, 중시적 신뢰, 미시적 신뢰 모두 공간적 근접성이 매우 큰 국지적 범위에서 대부분 형성되고, 신뢰형성 수준이 높을수록 연계의 공간적 범위는 국가적 범위, 국제적 범위로 확대된다. 셋째, 이러한 현상은 구매연계보다 판매연계에서, 제공하는 서비스 영역이 클수록, 수직적 연계보다 수평적 연계에서, 기업 간 관계가 발전할수록, 아웃소싱보다 공급사슬관리로 업무가 진행될 때 더욱 뚜렷하게 나타난다.

• 대한치과교정학회지
• /
• 제51권3호
• /
• pp.166-178
• /
• 2021

Objective: To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. Methods: Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis. Results: The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = -0.42, p < 0.01) and inferior airway space (β = -0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. Conclusions: Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

• Structural Engineering and Mechanics
• /
• 제69권2호
• /
• pp.221-230
• /
• 2019

In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.

• Journal of Contemporary Eastern Asia
• /
• 제17권2호
• /
• pp.176-198
• /
• 2018

Environmental issues are among the most critical issues nowadays. These issues are no longer confined to individual countries, and international society has been progressing in building global dialogues since the early 1970s. Within these international efforts, Germany and Japan have played essential roles in global environmental governance. However, there are major differences in nation-level environmental policies in both countries. Governance based on network structure is more efficient than that based on hierarchy for solving complex problems. The network structure is formed through horizontal cooperation among various autonomous actors, and the relationship intensity among actors is one of the key concepts in the governance. Using social network analysis as a framework to explain complicated societal structures explains how interaction among actors creates networks, and these networks further affect their interactions. The purpose of this study is to investigate the structure of environmental policy governance as collaborative governance in Germany and Japan. To address this goal, this paper analyzes the relationship between the informational dimension of governance networks and its complement resource-sharing networks in both countries. The results show that the information-sharing networks have lower-level network influence on the resource-sharing networks as higher-level networks even if not all of the information factors have singular influences. The results suggest that the information-sharing networks may be one of the pieces of the puzzle for explaining this phenomenon in environmental governance in Germany and Japan.

• Computers and Concrete
• /
• 제27권2호
• /
• pp.99-109
• /
• 2021

Experimental and discrete element methods were used to investigate the effects of echelon non-persistent joint on the failure behaviour of joint's bridge area under uniaxial compressive test. Concrete samples with dimension of 150 mm×100 mm×50 mm were prepared. Uniaxial compressive strength and tensile strength of concrete were 14 MPa and 1MPa, respectivly. Within the specimen, three echelon non-persistent notches were provided. These joints were distributed on the three diagonal plane. the angle of diagonal plane related to horizontal axis were 15°, 30° and 45°. The angle of joints related to diagonal plane were 30°, 45°, 60°. Totally, 9 different configuration systems were prepared for non-persistent joint. In these configurations, the length of joints were taken as 2 cm. Similar to those for joints configuration systems in the experimental tests, 9 models with different echelon non-persistent joint were prepared in numerical model. The axial load was applied to the model by rate of 0.05 mm/min. the results show that the failure process was mostly governed by both of the non-persistent joint angle and diagonal plane angle. The compressive strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. It was shown that the shear behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the joint angle. The strength of samples increase by increasing both of the joint angle and diagonal plane angle. The failure pattern and failure strength are similar in both methods i.e. the experimental testing and the numerical simulation methods.

• 한국컴퓨터정보학회논문지
• /
• 제28권1호
• /
• pp.93-101
• /
• 2023

이 논문은 영상 카메라를 이용하여 교통 객체를 인식하고자 하는 경우, 영상 내 객체 인식 정확도를 높이기 위해 소실점을 이용하여 객체에 대한 3D 바운딩 박스를 생성하는 방법이다. 최근 인공지능을 이용하여 교통 영상 카메라로 촬영된 차량을 검출하고자 하는 경우 이 3D 바운딩 박스 생성 알고리즘을 적용하고자 한다. 카메라 설치 각도와 카메라가 촬영한 영상의 방향성을 분석하여 종 방향 소실점(VP1)과 횡 방향 소실점(VP2)을 도출하고 이를 기반으로 분석 대상 동영상에서 이동하는 객체를 특정하게 된다. 이 알고리즘을 적용하면 감지된 객체의 위치, 종류, 크기 등 객체 정보 검출이 용이하고, 이를 자동차와 같은 이동류에 적용하는 경우 이를 트래킹하여 각 객체가 이동한 위치와 좌표, 이동속도 및 방향 등을 알 수 있다. 실제 도로에 적용한 결과 트래킹이 10% 향상되었으며 특히 음영지역(큰 차에 가려진 극히 적은 차량 부위)의 인식율과 트래킹이 100% 개선되는 등 교통 데이터 분석 정확성을 향상시킬 수 있었다.