• Title/Summary/Keyword: Support Boundary

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Reducing the wind pressure at the leading edge of a noise barrier

  • Han, Seong-Wook;Kim, Ho-Kyung;Park, Jun-Yong;Ahn, Sang Sup
    • Wind and Structures
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    • v.31 no.3
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    • pp.185-196
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    • 2020
  • A method to reduce the wind pressure at the leading edge of a noise barrier was investigated by gradually lowering the height of a member added to the end of the noise barrier. The shape of the lowered height of the added member was defined by its length and slope, and the optimal variable was determined in wind tunnel testing via the boundary-layer wind profile. The goal of the optimal shape was to reduce the wind pressure at the leading edge of the noise barrier to the level suggested in the Eurocode and to maintain the base-bending moment of the added member at the same level as the noise-barrier section. Using parametric wind tunnel investigation, an added member with a slope of 1:2 that protruded 1.2 times the height of the noise barrier was proposed. This added member is expected to simplify, or at least minimize, the types of column members required to equidistantly support both added members and noise barriers, which should thereby improve the safety and construction convenience of noise-barrier structures.

Stress Intensity Factors for Axial Cracks in CANDU Reactor Pressure Tubes (CANDU형 원전 압력관에 존재하는 축방향 균열의 응력확대계수)

  • Lee, Kuk-Hee;Oh, Young-Jin;Park, Heung-Bae;Chung, Han-Sub;Chung, Ha-Joo;Kim, Yun-Jae
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.1
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    • pp.17-26
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    • 2011
  • CANDU reactor core is composed a few hundreds pressure tubes, which support and locate the nuclear fuels in the reactor. Each pressure tube provides pressure boundary and flow path of primary heat transport system in the core region. In order to guarantee the structural integrity of pressure tube flaws which can be found by in-service inspection, crack growth and fracture initiation assessment have to be performed. Stress intensity factors are important and basic information for structural integrity assessment of planar and laminar flaws (e. g. crack). This paper reviews and confirms the stress intensity factor of axial crack, proposed in CSA N285.8-05, which is an fitness-for-service evaluation code for pressure tubes in CANDU nuclear reactors. The stress intensity factors in CSA N285.8-05 were compared with stress intensity factors calculated by three methods (finite element results, API 579-1/ASME FFS-1 2007 Fitness-For-Service and ASME Boiler and Pressure Vessel Code Section XI). The effects of Poisson's ratio and anisotropic elastic modulus on stress intensity factors were also discussed.

A Study on Multi-Orientation and Surveying Technology for TS and RTK-GPS (지상측량장비(TS와 RTK-GPS)에 의한 다자간 측량 및 표정에 관한 연구)

  • Tcha, Dek-Kie;Lee, In-Su;Kim, Su-Jeong
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2009.04a
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    • pp.119-123
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    • 2009
  • In the areas of civil engineering or cadastral surveying, multi-orientation process such as setting out boundary mark is regarded as one of the important tasks, measuring land feature and indicating acquired data to the grounds. In case of using dual frequency receiver and TS(total station), there are much advantages in setting out surveying results in the field. However, it costs very expensive and the equipments for enhancing correctness are very complex. In this study, technical factor was reviewed in which single frequence receiver and TS, comparatively cheap and easy to establish a system, was connected into TS(Total Station) in order to make easy to orientation and setting out. As a result of this study, it was possible to support GPS and TS surveying and set out it by short distance wireless communication method using single frequency GPS receiver. And by developing the system, it also could lessen the time of setting out in large areas and difficulty of the surveyors in the field.

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ALGEBRAIC CORRECTION FOR METAL ARTIFACT REDUCTION IN COMPUTED TOMOGRAPHY

  • Jeon, Kiwan;Kang, Sung-Ho;Ahn, Chi Young;Kim, Sungwhan
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.18 no.2
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    • pp.157-166
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    • 2014
  • If there are metals located in the X-ray scanned object, a point outside the metals has its range of projection angle at which projections passing through the point are disturbed by the metals. Roughly speaking, this implies that attenuation information at the point is missing in the blocked projection range. So conventional projection completion MAR algorithms to use the undisturbed projection data on the boundary of the metaltrace is less efficient in reconstructing the attenuation coefficient in detailed parts, in particular, near the metal region. In order to overcome this problem, we propose the algebraic correction technique (ACT) to utilize a pre-reconstructed interim image of the attenuation coefficient outside the metal region which is obtained by solving a linear system designed to reduce computational costs. The reconstructed interim image of the attenuation coefficient is used as prior information for MAR. Numerical simulations support that the proposed correction technique shows better performance than conventional inpainting techniques such as the total variation and the harmonic inpainting.

The Development of Extended Urban Land Information System for Sustainable Urban Management

  • Koh, June-Hwan
    • Korean Journal of Geomatics
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    • v.1 no.1
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    • pp.61-67
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    • 2001
  • This study aims to develop the Extended Urban Land Information System (EULIS) which can support the sustainable urban management. Although the existing Urban Land Use Information system (ULUIS) that aids the micro-level land use information is a good means for the understanding of urban spatial structure and district-level planning and management (such as urban design, redevelopment planning and district-level transportation planning, etc.), it has some limitations in supplying the information for sustainable urban management, such as environmental and traffic analysis, urban infrastructure's carrying capacity analysis, etc. The EULIS is designed to efficiently supply the information for sustainable urban management. For the successful construction of EULIS, the followings have to be considered. 1) the integration of topographic maps which contain the building's footprints and cadastral maps which contain the parcel's boundary, 2) the integration of EULIS and FM (Facility Management) system for the full utilization of information about capacity analysis of infrastructure, 3) the construction of standardized georeferencing system and spatial unit for the combined use of environment and traffic census data. This study shows 1) why EULIS is needed for the sustainable urban management and which elements are needed for the system,2) the E-R data model for the EULIS, 3) the strategies for the construction of EULIS and 4) the conclusion.

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Comparative Evaluation of Catchment-wide Solar Radiation to Locate Silver-town (실버타운 입지를 위한 집수구역별 일사량 비교평가)

  • Choi, Seon-Jeong;Um, Jung-Sup
    • Journal of the Korean Solar Energy Society
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    • v.34 no.5
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    • pp.11-22
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    • 2014
  • It is usual to determine silver-town location by people's experienced knowledge or intuition considering many different type of thematic variables simultaneously. This paper is primarily intended to locate sunny silver-town according to catchment-wide solar radiation as single key variable. GIS based solar simulation realistically identified catchment-wide solar radiation in the study area using large scale spatial precision. More than 90% over the worst catchment were identified shadow surfaces while the optimal catchment was heavily covered by sunny radiation surfaces. It is confirmed that standard GIS technology can offers the viable method of measuring and comparing the catchment-wide solar radiation. Guidelines for a replicable methodology are presented to provide a strong theoretical basis for the standardization of factors involved in locating the sunny silver-town; delineation of catchment boundary, solar simulation, catchment-wide comparison etc. They could be used as an evidence to determine sunny catchment in comparison with other catchment, based solar simulation. It is anticipated that this research output could be used as a valuable reference to confirm the potential of introducing the new concept of "catchment specific solar radiation" to support more scientific and objective decision-making in the process of locating silver town.

A Study on the Partnership for Activating of University Town in Seoul - Focused on Campus Fence Afforestation Project and the District Unit Plan for Renovating Campus Town Streets of Hanyang University - (서울시 대학가 활성화 계획과정의 파트너십 연구 - 한양대학교 대학가 환경정비형 지구단위계획 및 담장개방녹화사업 중심으로 -)

  • Park, Jin-A;Mok, Ik-Su;Kang, Woo-Seok
    • Journal of the Korean Institute of Educational Facilities
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    • v.15 no.4
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    • pp.26-37
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    • 2008
  • Because the university campuses in Seoul have changed to the urban campus type that the boundary of the campus is close to the urban tissue, the relationship between local societies and universities has got more important than before. Recently, through the support of Seoul metropolitan government, some projects for activating campus towns in Seoul have been proceeded. There are two distinctive projects. One is the campus fence afforestation project, and another is the district unit plan for the physical environment improvement of commercial streets around the campus in Seoul. The goal of this study is to analyze the government-university-community partnership for implementation of these two projects related to the model projects and the Hanyang university campus town as the exemplary government-university-community partnership, and to make practical application of other campus town projects to need the harmonious partnership between university neighborhoods and universities.

″A Study on the Stress and Wave Propagation in Transversely Impacted Composite Laminates″

  • Ahn, Kook-Chan;Kim, Nam-Kyung
    • Journal of the Korean Society of Safety
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    • v.7 no.1
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    • pp.39-45
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    • 1992
  • The impulsive stress and wave propagation of a glass/epoxy laminate subjected to the transverse low-velocity impact of a steel ball are investigated theoretically and experimentally. A plate finite element model based on Whitney and Pagano's theory In consunchon with experimental contact laws is used for the theoretical investigation. The specimens fo, statical indentation and impact test we composed of [0/45/0/-45/0]$_{2s}$ and [90/45/90/-45/90]$_{2s}$ stacking sequences and have clamped-simply supported boundary conditions. Finally, these two results are compared and then the impulsive stress and wave propagation characteristics of this laminated composite are studied.ied.

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Solution method for the classical beam theory using differential quadrature

  • Rajasekaran, S.;Gimena, L.;Gonzaga, P.;Gimena, F.N.
    • Structural Engineering and Mechanics
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    • v.33 no.6
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    • pp.675-696
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    • 2009
  • In this paper, a unified solution method is presented for the classical beam theory. In Strength of Materials approach, the geometry, material properties and load system are known and related with the unknowns of forces, moments, slopes and deformations by applying a classical differential analysis in addition to equilibrium, constitutive, and kinematic laws. All these relations are expressed in a unified formulation for the classical beam theory. In the special case of simple beams, a system of four linear ordinary differential equations of first order represents the general mechanical behaviour of a straight beam. These equations are solved using the numerical differential quadrature method (DQM). The application of DQM has the advantages of mathematical consistency and conceptual simplicity. The numerical procedure is simple and gives clear understanding. This systematic way of obtaining influence line, bending moment, shear force diagrams and deformed shape for the beams with geometric and load discontinuities has been discussed in this paper. Buckling loads and natural frequencies of any beam prismatic or non-prismatic with any type of support conditions can be evaluated with ease.

A Study on the Self Regulatory Management Model of Coastal Fisheries in Korea (우리나라 연안어업의 자율관리 모델 개발에 관한 연구)

  • 이상고;신용민
    • The Journal of Fisheries Business Administration
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    • v.35 no.1
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    • pp.87-115
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    • 2004
  • During the last decade the co - management concept has gained increasing acceptance as a potential way forward to improve fisheries management performance. It has, however, at the same time become increasingly evident that the co - management concept is not clearly defined and means very different things to different people. In this article, we attempt to development of self regulatory management model of coastal fisheries in Korea, and to present a more comprehensive understanding of fisheries co - management and community - based fisheries management and to summarise the experiences with both the positive outcomes and the problems in actual implementation. The Korean style of fisheries co - management system such as a fisheries self - governance & self - management system has been become a way to activate social processes and involve fishers in Korea coastal fisheries management. As results of this study, the policy recommendation to improve the effectiveness of implementation of this system are summarized. For the effective implementation of this system, some of the supplementary developments are needed as fellows. \circled1 establishment of communities on regional basis. \circled2 establishment of communities consist of coastal fishermen. \circled3 establishment of boundary in coastal fishery. \circled4 reinforcement of government indirect support systems

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