• Spatial Information Research
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• 제21권2호
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• pp.1-9
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• 2013

최근 이동통신 기술의 발전으로 실내에서의 위치 획득 기술이 용이해지면서 실내 내비게이션 시스템에 대한 연구가 각광을 받고 있다. 최적화된 실내 내비게이션은 크고 복잡한 실내에서의 활동을 위해 빠른 경로를 제공한다. 그러나 기존의 실내 내비게이션 알고리즘 연구들에서는 공간 토폴로지 또는 실내 네트워크에 기반하여 대략적인 경로를 도출한다. 본 논문에서는 공간 토폴로지 분석과 실내 내트워크를 통합 분석하여 실내 경로를 계산하는 알고리즘을 제안한다. 제안 알고리즘은 전문적인 실내지도가 아닌 간소화된 실내 지도 데이터를 활용하여 실내 네트워크와 공간 토폴로지의 혼합 분석을 통해 실내 경로의 길이를 줄일 수 있다. 성능평가를 통해 FT-Indoornavi 알고리즘이 기존의 엘라스틱 알고리즘과 iNav 알고리즘보다 더 빨리 실내 경로를 계산할 수 있음을 보여준다.

• 한국의류산업학회지
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• 제17권6호
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• pp.881-894
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• 2015

The silver generation have clothing style of optimal daily life comparing than young generation because they do not participate a specific sport event but daily- life exercise. As the human body ages, the figure of the silver generation shows different body shape because upper body changes to curved figure including the belly and waist part. Therefore, clothing characteristics for the silver generation should be considered with proper function, design and textiles to optimize body movement. This study investigated various exercise types according to motion analysis of the silver generation in order to develop the design of the active T-shirts reflecting the structural properties and providing the optimum exercise circumstance. The results to consider design needs are as followed; As the T-shirts design for the flexible exercise which required frequent movement of upper body such as bending and waist twisting during body stretching, a stretch fabric applied to the waist part considering T-shirts allowance and length to make extreme elongation and support for well-fitting appearance of the T-shirts. As the T-shirts design for the instantaneous reactionary exercise, high elastic four-way stretch fabric is applied to the part of arm hole to optimize skeletal and muscle movement for entire body and arm work. As the T-shirts design for the endurance exercise such as climbing, cycling, and walking, the shoulder line of the back part has cutting line allowance to make optimum movement of the upper body but no change of the waist part.

• 한국터널지하공간학회 논문집
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• 제18권5호
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• pp.469-485
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• 2016

심부 터널 주변 암반의 파괴는 불연속면의 영향을 크게 받는 천부 터널 주변과 다르게 응력의 크기와 방향이 지배한다. 응력 지배 파괴의 양상은 응력 조건, 암석의 특성에 따라 연성과 취성으로 구분할 수 있으며 파석, 판상 파괴, 암석 파열 현상의 결과로 나타나는 V-형 홈 형태 취성 파괴 영역의 범위와 깊이는 심부 터널의 굴착과 보강 설계의 주요 인자이므로 이를 파악하는 것은 중요하다. 취성 파괴의 특성은 응력 조건에 따라 점착력 상실과 마찰력 전이로 구성된다는 점과 진행성 파괴라는 점이다. 본 연구는 이중 선형 절단 파괴 포락선과 탄성-탄소성 연계 해석과 점진적 탄소성 영역 확대라는 해석 절차와 방법을 도입하여 터널 주변 취성 암반의 파괴를 합리적으로 모사할 수 있는 3차원 수치 모델을 구현하였다. 이 수치 모델이 예상한 취성 파괴 영역의 깊이는 기존 사례 연구를 통한 경험식의 결과와 부합되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.640-649
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• 2010

Coarse granular materials such as gravel and crushed stone have been used as an important fill materials to large soil structure of railway, road, dam and so on. Although much studies for general soil materials have been carried out domestically, the studies for coarse materials were insufficient. Particularly, it is the level in which the study for dynamic properties(Elastic modulus and damping ratio) of coarse materials, applies the foreign country literature. This is due to the lack of large equipment for element test. But large soil structures made of coarse granular materials are generally important infrastructures. Therefore, the reliable design parameters for coarse materials should be obtained for safe and economic design, construction and maintenance. Triaxial test is the laboratory test method that is capable of controlling a confining pressure and boundary condition. In this project, we made a multi-purpose large triaxial testing system. This testing system is able to test coarse granular materials with maximum particle diameter of 100mm and support both the load control and displacement control. The load cell is installed inside of triaxial cell and the axial displacement is measured locally in order to control and measure more accurately in the small strain level. The verification test of this testing system was carried out with urethane verification specimens. So, from now on the useful information for coarse granular materials are expected to suggested by performing many tests with various material and condition.

• 한국정밀공학회지
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• 제22권10호
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• pp.114-120
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• 2005

Urethane is a high polymeric and elastic material useful in designing mechanic parts that cannot be molded with rubber or plastic material. In particular, urethane is high in mechanical strength and anti-abrasive. Hereby, a urethane coated aluminum wheel is used to support of the OHT vehicle moving back and forth to transport products. For the sake of verifying the safety of the vehicle, structural safety fur applied maximum dynamic load on a urethane wheel must be examined carefully while driving. Therefore, we performed a dynamic simulation on the OHT vehicle model and we determined the driving load. The area definition of applied load may be obtained from the previous study of Hertzian and Non-Hertzian contact force model having exact properties of contact material. But the static analysis is simulated after we have performed the actual contact area test for each load since the proper material properties of urethane have not been guaranteed. In this study, the method of distributing loads for each node is included. Finally, in coMParison with the results of analysis and load-displacement curve obtained from the compression test, we have defined the material properties of urethane. In the analysis, we verified the safety of the wheel. Finally, we performed a mode analysis using the obtained material properties. With these results, we presented a reliable finite element model.

• Structural Engineering and Mechanics
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• 제13권5호
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• pp.557-568
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• 2002

For the evaluation of the capability of a tubular member of an offshore structure to absorb the collision energy, a simple method can be employed for the collision analysis without performing the detailed analysis. The most common simple method is the rigid-plastic method. However, in this method any characteristics for horizontal movement and rotation at the ends of the corresponding tubular member are not included. In a real structural system of an offshore structure, tubular members sustain a certain degree of elastic support from the adjacent structure. End fixity has influences in the behaviors of a tubular member. Three-dimensional FEM analysis can include the effect of end fixity fully, however in viewpoints of the inherent computational complexities of the 3-D approach, this is not the recommendable analysis at the initial design stage. In this paper, influence of end fixity on the behaviors of a tubular member is investigated, through a new approach and other approaches. A new analysis approach that includes the flexibility of the boundary points of the member is developed here. The flexibility at the ends of a tubular element is extracted using the rational reduction of the modeling characteristics. The property reduction is based on the static condensation of the related global stiffness matrix of a model to end nodal points of the tubular element. The load-displacement relation at the collision point of the tubular member with and without the end flexibility is obtained and compared. The new method lies between the rigid-plastic method and the 3-demensional analysis. It is self-evident that the rigid-plastic method gives high strengthening membrane effect of the member during global deformation, resulting in a steeper slope than the present method. On the while, full 3-D analysis gives less strengthening membrane effect on the member, resulting in a slow going load-displacement curve. Comparison of the load-displacement curves by the new approach with those by conventional methods gives the figures of the influence of end fixity on post-yielding behaviors of the relevant tubular member. One of the main contributions of this investigation is the development of an analytical rational procedure to figure out the post-yielding behaviors of a tubular member in offshore structures.

• Structural Engineering and Mechanics
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• 제35권6호
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• pp.677-697
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• 2010

This paper focuses on geometrically non-linear static analysis of a simply supported beam made of hyperelastic material subjected to a non-follower transversal uniformly distributed load. As it is known, the line of action of follower forces is affected by the deformation of the elastic system on which they act and therefore such forces are non-conservative. The material of the beam is assumed as isotropic and hyperelastic. Two types of simply supported beams are considered which have the following boundary conditions: 1) There is a pin at left end and a roller at right end of the beam (pinned-rolled beam). 2) Both ends of the beam are supported by pins (pinned-pinned beam). In this study, finite element model of the beam is constructed by using total Lagrangian finite element model of two dimensional continuum for a twelve-node quadratic element. The considered highly non-linear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. In order to use the solution procedures of Newton-Raphson type, there is need to linearized equilibrium equations, which can be achieved through the linearization of the principle of virtual work in its continuum form. In the study, the effect of the large deflections and rotations on the displacements and the normal stress and the shear stress distributions through the thickness of the beam is investigated in detail. It is known that in the failure analysis, the most important quantities are the principal normal stresses and the maximum shear stress. Therefore these stresses are investigated in detail. The convergence studies are performed for various numbers of finite elements. The effects of the geometric non-linearity and pinned-pinned and pinned-rolled support conditions on the displacements and on the stresses are investigated. By using a twelve-node quadratic element, the free boundary conditions are satisfied and very good stress diagrams are obtained. Also, some of the results of the total Lagrangian finite element model of two dimensional continuum for a twelve-node quadratic element are compared with the results of SAP2000 packet program. Numerical results show that geometrical nonlinearity plays very important role in the static responses of the beam.

• 한국지진공학회논문집
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• 제9권2호통권42호
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• pp.47-58
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• 2005

이산폰툰형 부유식교량의 시간영역 지진응답해석을 지진파의 공간분포를 고려하여 수행하였다. 지반운동의 공간변화는 파의 통과 영향, 엇결성 뎡향 및 국부지반 영향을 반영하는 결맞음 함수 모델로 고려하였다. 부유식 교량의 상부구조는 공간뼈대요소와 탄성현수케이블요소를 이용하여 모델링 하였고, FHWA 가이드라인의 스프링 모델을 사용하여 교대의 지반 구조물 상호작용에 대한 영향을 고려하엿으며, 경계요소법으로 산정한 폰툰 동수력계수의 주파수 의종성을 고려하기 위해서 시간지연함수를 사용하였다. 지반운동의 공간변화를 고려한 다중지점 지진입력을 교량의 양단에 도입하였고 응답의 시간이력을 동시 가진 시와 비교하였다. 장주기의 동적특성을 갖는 이산폰툰형 부유식 교량의 지진응답 해석에서 지반운동의 공간분포를 고려할 경우에 주몰할만한 응답의 증폭이 나타날 수 있음을 확인하였다.

• 한국지진공학회논문집
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• 제24권5호
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• pp.219-232
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• 2020

The slip-weakening model developed by Ohnaka and Yamashita is extended over the breakdown zone by equating the scaling relationships for the breakdown zone and the whole rupture area. For the extension, the study uses the relationship between rupture velocity and radiation efficiency, which was derived in the theory of linear elastic fracture mechanics, and the definition of f_max given in the specific barrier model proposed by Papageorgiou and Aki. The results clearly show that the extended scaling relationship is governed by the ratio of rupture velocity to S wave velocity, and the velocity ratio can be determined by the ratio of characteristic frequencies of a Fourier amplitude spectrum, which are corner frequency, f_c, and source-controlled cut-off frequency, f_max, or vice versa. The derived relationship is tested by using the characteristic frequencies extracted from previous studies of more than 130 shallow crustal events (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan. Under the assumption of a dynamic similarity, the rupture velocity estimated from f_max/f_c and the modified integral timescale give quite similar scale-dependence of the rupture area to that given by Kanamori and Anderson. Also, the results for large earthquakes show good agreement to the values from a kinematic inversion in previous studies. The test results also indicate the unavailability of the spectral self-similarity proposed by Aki because of the scale-dependent rupture velocity and the rupture velocity-dependent f_max/f_c; however, the results do support the local similarity asserted by Ohnaka. It is also remarkable that the relationship between the rupture velocity and f_max/f_c is quite similar to Kolmogorov's hypothesis on a similarity in the theory of isotropic turbulence.

• Archives of Plastic Surgery
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• 제34권2호
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• pp.176-180
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• 2007

Purpose: Pitanguy conducted a series of anatomical studies on "dermocartilaginous ligament" of the nose. However, information on its structure is as yet insufficient, especially in terms of its origin, insertion, and relationships with surrounding tissues. In addition, some of the histologic findings described by Pitanguy are controversial. The present study was undertaken to clarify the anatomy of the "dermocartilaginous ligament". Methods: Sixteen cadaver noses were examined macroscopically and histologically to determine the presence, origin, insertion, composition, and relationship of the "dermocartilaginous ligament" with surrounding structures. Results: The structure originated from the deep layer of the transverse nasalis muscle and terminated at the caudal edge of the septal cartilage in all 16 cadavers. However, in three cadavers the insertion extended to the orbicularis oris muscle. No direct connection was found between the structure and dermis of dorsal nasal skin. The dermocartilaginous ligaments were mainly composed of a condensation of thin collagen bundles, which were interwoven and without any regular orientation. Elastic fibers were also present in small numbers, and there were few amorphous ground substances. Neither muscle fibers nor chondrocytes was identified within dermocartilaginous ligaments. Conclusion: Our macroscopic and histologic findings of the structure do not support the use of the term "dermocartilaginous ligament". According to its origin, insertion, and histologic findings, we recommend that this structure be referred to as the "median musculocartilaginous fascia".