• Title/Summary/Keyword: long period structure

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Damage Estimation of Structures by Second Order Modal Perturbation (2차 모우드 섭동법에 의한 구조물의 손상도 추정)

  • 홍규선;윤정방;류정선
    • Computational Structural Engineering
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    • v.5 no.3
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    • pp.119-126
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    • 1992
  • Most civil engineering structures such as bridges, power plants, and offshore platforms are apt to suffer structural damages over their service lives caused by adverse loadings, such as earthquakes, wind and wave forces. Accumulation of structural damages over a long period of time might cause catastrophic structural failure. Therefore, a methodology for monitoring the structural integrity is essential for assuring the safety of the existing structures. A method for the damage assessment of structures by the second order inverse modal perturbation technique is presented in this paper. Perturbation equation consists of a matrix equation involving matrices of structural changes(stiffness and mass matrix changes) and matrices of modal property changes(natural frequency and mode shape changes). The damages of a structure are represented as changes in the stiffness matrix. In this study, a second order perturbation equation is formulated for the damage assessment of structures, and solved by an iterative procedure. The effectiveness of the proposed method has been investigated through a series of example analysis. The estimated results for the structural damage indicated that the present method yields resonable estimates for the structural changes.

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A Study on the Self-similarity Found in Fashion Design - Focusing on the Designs of Viktor & Rolf - (패션디자인에 나타나는 자기유사성에 관한 연구 - Viktor & Rolf의 디자인을 중심으로 -)

  • Kim, Yonson
    • Journal of the Korean Society of Costume
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    • v.64 no.7
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    • pp.97-113
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    • 2014
  • The study aims to determine the significance and characteristics of self-similarity inherent in natural objects or phenomena, the existence of self-similarity in design created by fashion designers, and the traits and internal significance implied in self-similarity and their effects on fashion. The subject of the study is Viktor & Rolf, and the scope of the study is the collections created from 2001 to 2014, which include designs implemented in their early years and those unveiled in the media. Self-similarity means attributes of a fractal structure appearing without change in the original form, even after modification of scale or direction in terms of shape or phenomena. As self-similarity is applied to the arts and design sectors, it leads people to pay attention to fundamental characteristics and intrinsic forms as a factor of expressing a unique creative world. Analysis of Viktor & Rolf collections generated ribbons, overlapping/juxtaposition, side decorations and exaggerated design elements as basic units of self-similarity. These factors had self-similarity rates as high as 84%. Self-similarity was established as design elements formed in the incipient stage were repeated in a certain form, and continued for a long period of time. It served as an element that recognizes design and a fashion designer at the same time. Characteristics of self-similarity appearing in Viktor & Rolf collections can be summarized as homeostasis based on an equivalent relationship, balance based on self-organization, reducibility into essential elements, and uniqueness based on odd shapes. These characteristics influenced the pursuit of consistent brand image, the maintenance of a fashion designer's creative world, the formation of styles and the expression of a fashion designer's identity.

A Study on the Mechanical Unconscious of Japan and Schizo-Analysis of Japanese Traditional Space Design (일본의 기계적 무의식과 전통공간디자인의 분열분석에 관한 연구)

  • Park, Kyung-Ae
    • Korean Institute of Interior Design Journal
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    • v.21 no.2
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    • pp.74-83
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    • 2012
  • This study is an historical consideration about the modern discourse of Japanese spacial tradition driven from cultural background. The purpose of this study is to establish a cartographic map of historical progress, and to shed light on the forming of identity in Japanese traditional space design on the schizo-analytical aspect. It adopts F. Guattari's psychoanalytic theory to the structural analysis of Japanese traditional space design. The process of this study is illustrated as follows: At first, it mentions Guattari's theory of Mechanical Unconscious, Schizo-analysis, Cartography, and Abstract machine as theoretical background. And, it considers the identity of Japanese traditional space constructed by various cultural sign over a long period of time as the statement of apriority. Secondly, it clarifies semiologic generation of Japanese traditional space design based on the analysis of spacial morphemes about each design stemmed from modernization process of Japan. Thirdly, it ascertains semiologic topography the representamens draw, i.e. schizo-analytic cartography from synchronic and diachronic point of view. Fourthly, it analyses traditional discourse structure in terms of generative schizo-analysis and transformational schizo-analysis with four categories- object, style, concept, strategy. Through this process, it studies the reproduction of Japanese tradition in terms of the 'social organization', and explores the way vitalized on the space-time coordinate system by the schizo-analysis of the mechanical unconscious. In conclusion, it clarifies Generative-schizo is accomplished in the level of formulating representamen, and Transformational-Schizo involves experimental mind that induce implantation of the heteromorphic elements and avant-garde experiments of abstract mechanical operation in the schizo-analysis of Japanese traditional space design. The significance of this study is to arrange an opportunity of introspection on Korean-ness seriously from inspecting logic of Japan-ness closely in traditional space design.

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A Study on the Interface Micromotions of Cementless Artificial Hip Replacement by Three-Dimensional FEM (무시멘트형 인공고관절 대치술후 초기의 경계면 미세운동의 3차원 FEM 연구)

  • Kim, S.K.;Chae, S.W.;Choi, H.Y.
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.12
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    • pp.71-74
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    • 1994
  • In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony ingrowth and secondary long term fixation. Bone ingrowth depends strongly on relative micromotion and stress distributions at the interface. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone-prosthesis interface, Hence an accurate evaluation of interface behavior and stress/strain fields in the bone implant system may be relevant for better understanding of clinical situations and improving THA design. However, complete evaluation of load transfer in the bone remains difficult to assess experimentally, Hence, recently finite element method (FEM) was introduced in orthopaedic research field to fill the gap due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional numerical finite element model which is composed of totally 1179 elements off and 8 node blick. We also analyzed the micromotions at the bone-stem interface and mechanical behavior of existing bone prosthesis for a loading condition simulating the single leg stance. The result indicates that the values of relative motion for this well fit Multilock stem were $150{\mu}m$ in maximum, $82{\mu}m$ in minimum, and the largest relative motion developed in medial region of proximal femur with anterior-posterior direction. The proximal region of the bone was much larger in motion than the distal region and the stress pattern shows high stress concentration on the cortex near the tip of the stem. These findings indicates that the loading in the proximal femoral bone in the early postoperative situation can produce micromotions on the interface and clinically cementless TEA patient should not be allowed weight bearing strictly early in the postoperative period.

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Site suitability for conifer plantation and a new challenge to utilize deciduous trees

  • NAGASHIMA, Keiko
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2018.10a
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    • pp.24-24
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    • 2018
  • Degraded plantation forests are increasing because of unfavorable forestry conditions prevailing in Japan, including falling timber prices, increasing operational costs, and aging and declining forestry workforce. To remedy this situation, appropriate management strategy is required. This study introduces the challenges of Odai Town, Mie Prefecture that employed a new management strategy by evaluating site suitability for conifer forests and that proposes a new forest management regime of planting deciduous trees in unsuitable sites. The site suitability for conifer forests was evaluated from two aspects: the natural site conditions and the relationship among site conditions, growth, and damage by Anaglyptus subfasciatus Pic. in Cryptomeria japonica D. Don and Chamaecyparis obtusa Sieb. Et Zucc. forests. By analyzing the relationship among site conditions, growth, and insect damage based on field data obtained in plantation forests, growth evaluation and insect damage evaluation maps were developed. Based on the natural forest investigation, natural site condition maps for C. japonica and C. obtusa were established. Furthermore, by integrating these evaluation maps with the forest road maps showing the accessibility to the forest, the forest management regime for the whole plantation area of Odai Town was established. The forest management regime map indicates the sites suitable for forestry: suitable for long-rotation, short-rotation, and potential sites for short-rotation. The sites unsuitable for forestry were considered to be more suitable for broadleaved forests. Clear-cutting was conducted in a small area and different seral stage saplings (approximately 20 deciduous tree species) suitable to the site conditions were planted in an area of $80-120m^2$ protected by deer-fences. This might establish a forest composed of many species with a multilayer vertical forest structure in a short period. The planted saplings were distributed neither randomly nor uniformly to reflect the natural distribution of trees in the forest. A challenge to develop new products using the deciduous trees has started, such as wood chips for preparing smoked food, essential oil, and deodorizer. As these challenges have just begun, their effects on enhancing sustainable resource management are still being monitored. Even with the challenges, this regime can be of high value as a management strategy to remedy the situation of expansion of degraded forests in Japan.

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Application of Targis-Vectris Provisional Restorations for an Oro-Maxillofacial Cancer Patient: A Case report (악성암종 수술 환자에서 임시수복물로서 Targis-Vectris의 응용)

  • Kim, Jin-Man;Han, Jung-Suk;Lee, Sun-Hyung;Yang, Jae-Ho;Lee, Jae-Bong
    • Journal of Dental Rehabilitation and Applied Science
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    • v.18 no.2
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    • pp.113-118
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    • 2002
  • Conventional radiograph, computed tomograph (CT), magnetic resonance image (MRI) are commonly used methods for diagnosis of oro-maxillofacial cancer. MRI is an effective tool to verify soft tissue lesion however, metal produces black artifacts in the image. Therefore, metal structure should be removed before taking MRI to diagnose head and neck cancer patients. A 52-year-old female patient with adenocarcinoma in the posterior right soft palate was referred to take a MRI before surgery. She has 7-unit porcelain fused to metal bridge in the maxilla. Eight-unit Tagis-Vectris fixed partial denture was fabricated to replace her existing PFM bridge to take a MRI without any artifact before and after surgery. The patient satisfied with her restorations in terms of esthetics, function after 11 months. Even though minor staining was detected, Tagis-Vectris restoration fixed partial denture was intact during observation period.

Institutional Analysis on Organizational Changes of Korean Medicine Hospitals (보건의료 제도환경에 따른 한방병원의 변화 - 제도주의적 관점의 적용 -)

  • Park, Minjung;Lim, Buoungmook;Cha, Wungseok;You, Myoungsoon
    • The Journal of Korean Medicine
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    • v.35 no.1
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    • pp.145-156
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    • 2014
  • Objectives: Korean medicine hospitals, since they first emerged in the early 1970s, have rapidly become a new member of the hospital population. As it was a new organizational frame for traditional medicine, we tried to analyze the changes of Korean medicine hospitals coping with institutional environment and their relative positioning in the whole health care sector. Methods: On the basis of Scott and his colleagues' identification of the three components of institutional environments, changes in organizational logics, actors, and governance of Korean medicine hospitals during the period from 1971 to 2010 were analyzed. Results: First, Similar to previous literature on institutional eras of Korean health sector, three distinct periods were characterized: the foundation of Korean medicine hospitals to consolidate the legal status(1971~1986), a rapid increase of entrepreneurial hospitals through cultural-cognitive legitimacy(1987~2001), and the reinforcement of specialization and competition(2002~present). Conclusions: Results suggested that: (1) changes in institutional environments hada heavy impact on structural and behavioral changes among Korean medicine hospitals, but the pace was slower than that of western medicine hospitals. (2) In structure, Korean medicine hospitals have positioned themselves as unofficial long-term care hospitals, focusing on chronic diseases(e.g. cerebrovascular disease). Our study demonstrated that organizational theories can provide useful framework for the analysis of Korean medicine and related policies. Indeed, one of the most important implications of this study is that understanding changes in institutional environments is important to understand the process of how members of the health care sector live, grow, change, decline and survive.

The Aesthetics of Korean Traditional Costume Affected by Non-Dualistic Theory of Buddhism (불이[不二] 사상에 영향을 받은 전통복식의 조형미)

  • Seo, Bong-Ha;Kim, Min-Ja
    • Journal of the Korean Society of Costume
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    • v.57 no.3 s.112
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    • pp.165-175
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    • 2007
  • Religion affects all the dimension of human beings, and at the same time it forms one dimension of human beings. Costume Is considered as a result that reflects the phases of the time and the characteristics of a wearer. Costume, also, has been influenced by religion that has led one's belief, social spirit and culture for a long period of time. The Eastern aesthetics has expanded the area of thoughts with the concepts that originated from Buddhism, Taoism, and Confucianism. Among the concepts, Non-Dualistic Theory is the core idea of Buddhism.'rho theory contains the moaning that one should not lean to one side between existence and nonexistence and should not be obsessed with the center. It was the most powerful Buddhistic idea that had an influence on Asian aesthetics. Korean traditional costume is not an exception. This study has a significance that it was conducted to understand the relation between religious principle and traditional custom through mainly using documentary records. The formative characteristics of Korean traditional costume influenced by Non-Dualistic Theory ran be summarized as non-structure like, indeterminate forms, amorphousness and anti-decoration such as plainness, temperance and achromatic color. Aesthetic value was expressed through 'the aesthetic of emptiness', 'the aesthetic of hiding', and 'the aesthetic of nature'. Although the appearance of a religious symbol can change, an essential element in religion lasts as human society remains. Although our clothing culture has converted to western style, Korean traditional aesthetics is placed deep inside of 'the Koreans' spirit and has a consistent effect on our overall culture of clothing.

Comparison of Modeling Methods of a Pile Foundation in Seismic Analysis of Bridge Piers (교각의 내진설계를 위한 말뚝기초의 모델링 기법 비교)

  • 김나엽;김성렬;전덕찬;김명모
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.6
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    • pp.25-32
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    • 2002
  • In the seismic designing of bridges, the pile foundation of bridge piers generally have been modeled to have a fixed end for its convenience and conservative designing. The fixed-end assumption, however, produces very conservative results in terms of the pier forces. Therefore, many other design methods are evolved to consider the flexibility of the pile foundation. In this study, the response spectrum analysis was performed for a bridge pier having a pile foundation. The shear force, moment, and displacement, which occurred at the pier column under an earthquake loading, were compared to analyze the effects of the modeling method, soil condition and the input earthquake response spectrum. In most cases, the fixed-end model gives larger design forces than flexible foundation models. However, when a long period earthquake is applied to the bridge pier on a soft clay foundation, it is found that the flexible foundation models give larger design forces than the fixed-end model. In the end, the reliability of several flexible foundation models was verified by comparing their results with those of a numerical analysis that considers the soil-structure interaction phenomenon in a rigorous manner.

Evaluation of Compressive Strengths of Tubular Steel Members According to Corrosion Damage and Shape (원형 강관의 국부 부식손상 수준 및 손상형태에 따른 압축강도 성능평가)

  • Ahn, Jin Hee;Nam, Dong Kyun;Lee, Won Hong;Huh, Jungwon;Kim, In Tae
    • Journal of Korean Society of Steel Construction
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    • v.28 no.4
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    • pp.213-222
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    • 2016
  • For a steel structure with long service period, structural performance can be changed or decreased by corrosion damage occurred under severe corrosion environment condition. In this study, to examine compressive strength and behavior of circular steel member depending on corrosion damage, compressive loading tests were conducted using circular steel member with artificial corrosion damage which was applied by mechanical process and hand drill. From test results, local corrosion area and pattern is related to their structural performance. Their lcoal bucklings were occurred near artificially sectional damaged part. Reduction in compressive strength of circular steel member was also suggested according to their corroded part and damage.