• Title/Summary/Keyword: macro-elements

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A Study on the Development of Eco-friendly Environmental Indicators for Saemangeum Project (새만금사업의 친환경개발지표 설정 연구)

  • Ryu, Jae-Hong;Lee, Sang-Hoon;Koo, Ja-Kon
    • Journal of Environmental Impact Assessment
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    • v.15 no.4
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    • pp.279-288
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    • 2006
  • Saemangeum reclamation project was started in 1991 with the purpose of eco-friendly reclamation, but without clear definition of eco-friendliness. This study was carried out to find out the environmental indicators to define and evaluate the eco-friendliness of Saemangeum project. The methodology to identify the indicators included the analysis of similar reclamation projects, professional discussions, and Delphi survey. The eco-friendly indicators are theoretically based on the five elements of eco-friendliness; 1) resource consumption, 2) energy consumption, 3) pollution emission, 4) bio-diversity, 5) social amenity. The 69 indicators were explained in detail for the convenient use of the indicators by the potential users. The 69 indicators were classified into three categories such as pre-evaluation, process evaluation, and post-evaluation. In terms of spatial consideration, the 69 indicators were classified into two categories such as direct influence area and indirect influence area. Also the 69 indicators were classified into 7 categories: 1) sea, 2) lake, 3) agricultural land use, 4) industrial land use, 5) residential land use, 6) tourism land use, and 7) environmental land use. Twenty core indicators were selected from the 69 indicators by surveying the importance of each indicator. The core indicators are recommended in case of time and budget strain. When there are few quantitative data accumulated for the reclamation project, 5 macro indicators are recommended to be used. Macro indicators are qualitative in nature, and may be used in order to evaluate the overall eco-friendliness of a reclamation project.

A Study on the Solution of Unsold Houses through User Centered Marketing Strategies (수요자 중심의 마케팅 전략을 통한 미분양 주택 해소방안에 관한 연구)

  • Lee, Gwang-Kyun;Lee, Joo-Hyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.3
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    • pp.1318-1326
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    • 2014
  • The change of concept about real estate marketing and the solution about unsold houses are getting important nowadays. This paper is analyzing the solution of unsold houses as location environment, residential environment, macro environment, and marketing, and research question is which elements are important to real users. In addition, this paper is analyzing on impact relationship in terms of real users' buying intention about unsold houses and satisfaction of price of selling a house (price of selling a house, rise in housing value) by PLS structural equation. To sum up, first, macro environment, residential environment, location environment is statistically valued on the satisfaction of price of selling a house. However, marketing strategic is not impacted on the satisfaction of price of selling. Second, macro environment, marketing strategic, satisfaction of selling a house is statistically valued on buying intention.

Continuum Based Plasticity Models for Cubic Symmetry Lattice Materials Under Multi-Surface Loading (다중면 하중하에 정방향 대층구조를 가진 격자재료의 연속적인 소성모델)

  • Seon, Woo-Hyun;Hu, Jong-Wan
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.2 no.3
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    • pp.1-11
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    • 2011
  • The typical truss-lattice material successively packed by repeated cubic symmetric unit cells consists of sub-elements (SE) proposed in this study. The representative continuum model for this truss-lattice material such as the effective strain and stress relationship can be formulated by the homogenization procedure based on the notation of averaged mechanical properties. The volume fractions of micro-scale struts have a significant influence on the effective strength as well as the relative density in the lattice plate with replicable unit cell structures. Most of the strength contribution in the lattice material is induced by axial stiffness under uniform stretching or compression responses. Therefore, continuum based constitutive models composed of homogenized member stiffness include these mechanical characteristics with respect to strength, internal stress state, material density based on the volume fraction and even failure modes. It can be also recognized that the stress state of micro-scale struts is directly associated with the continuum constitutive model. The plastic flow at the micro-scale stress can extend the envelope of the analytical stress function on the surface of macro-scale stress derived from homogenized constitutive equations. The main focus of this study is to investigate the basic topology of unit cell structures with the cubic symmetric system and to formulate the plastic models to predict pressure dependent macro-scale stress surface functions.

A curved shell finite element for the geometrically non-linear analysis of box-girder beams curved in plan

  • Calik-Karakose, Ulku H.;Orakdogen, Engin;Saygun, Ahmet I.;Askes, Harm
    • Structural Engineering and Mechanics
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    • v.52 no.2
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    • pp.221-238
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    • 2014
  • A four-noded curved shell finite element for the geometrically non-linear analysis of beams curved in plan is introduced. The structure is conceived as a sequence of macro-elements (ME) having the form of transversal segments of identical topology where each slice is formed using a number of the curved shell elements which have 7 degrees of freedom (DOF) per node. A curved box-girder beam example is modelled using various meshes and linear analysis results are compared to the solutions of a well-known computer program SAP2000. Linear and non-linear analyses of the beam under increasing uniformly distributed loads are also carried out. In addition to box-girder beams, the proposed element can also be used in modelling open-section beams with curved or straight axes and circular plates under radial compression. Buckling loads of a circular plate example are obtained for coarse and successively refined meshes and results are compared with each other. The advantage of this element is that curved systems can be realistically modelled and satisfactory results can be obtained even by using coarse meshes.

Analysis of side-plated reinforced concrete beams with partial interaction

  • Siu, W.H.;Su, R.K.L.
    • Computers and Concrete
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    • v.8 no.1
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    • pp.71-96
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    • 2011
  • Existing reinforced concrete (RC) beams can be strengthened with externally bolted steel plates to the sides of beams. The effectiveness of this type of bolted side-plate (BSP) beam can however be affected by partial interaction between the steel plates and RC beams due to the mechanical slip of bolts. To avoid over-estimation of the flexural strength and ensure accurate prediction of the load-deformation response of the beams, the effect of partial interaction has to be properly considered. In this paper, a special non-linear macro-finite-element model that takes into account the effects of partial interaction is proposed. The RC beam and the steel plates are modelled as two different elements, interacting through discrete groups of bolts. A layered method is adopted for the formulation of the RC beam and steel plate elements, while a special non-linear model based on a kinematic hardening assumption for the bolts is used to simulate the bolt group effect. The computer program SiBAN was developed based on the proposed approach. Comparison with the available experimental results shows that SiBAN can accurately predict the partial interaction behaviour of the BSP beams. Further numerical simulations show that the interaction between the RC beam and the steel plates is greatly reduced by the formation of plastic hinges and should be considered in analyses of the strengthened beams.

Nonlinear Analysis of Slender Double Skin Composite Walls Subjected to Cyclic Loading (주기하중을 받는 세장한 이중강판합성벽의 비선형해석)

  • Eom, Tae Sung;Park, Hong Gun
    • Journal of Korean Society of Steel Construction
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    • v.20 no.4
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    • pp.505-517
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    • 2008
  • A numerical analysis method was studied to predict the nonlinear behavior of slender double skin composite walls. For convenience in numerical analysis, the model for the double skin composite wall was developed as a macroscopic model that can predict nonlinear behavior with relatively simplified models. For the wall showing flexure-dominant behavior, a multiple layer model was used. Each layer was modeled with composite elements of concrete and steel plate. An X-type truss model was used for coupling beams showing shear-dominant behavior. To describe the cyclic behavior of concrete and steel elements, simplified cyclic models for the materials were proposed. The proposed analysis model was applied to isolated walls and coupled walls with rectangular or T-shaped cross-sections. The analytical results were compared with existing test results.

An Empirical Study on the Moderating Effect of Competitive Strategy on the Relationship between Information Technology Investment and Information Technology Effectiveness (정보기술투자와 정보기술 효과성 간의 관련성에 대한 경쟁전략의 조절효과)

  • Chung Hyun-Sik;Roh Jung-Gu
    • Management & Information Systems Review
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    • v.17
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    • pp.381-399
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    • 2005
  • During the past decade a great deal of attention has focused on the impact of IT investment. However, many related studies have frequently generated controversial or inconsistent results. These results imply that the relationship between IT investment and performance is complex and multifaceted. And empirical studies with new analytical techniques are badly needed to examine the way IT investment interacts with various organizational and environmental elements to influence corporate performance. Accordingly a study of IT investment needs to make a contingency approach to determining the level of IT investment based on the competitive strategy in a macro perspective. The basic purpose of this research is to analyse the relationship between IT investment and IT effectiveness and to identify the moderating effect of competitive strategy in the relationship. The results showed that there is no relationship between IT investment and IT effectiveness, and the competitive strategy can be considered as a significant moderating variable between IT investment and IT effectiveness.

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Experimental studies on the fatigue life of shape memory alloy bars

  • Casciati, Sara;Marzi, Alessandro
    • Smart Structures and Systems
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    • v.6 no.1
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    • pp.73-85
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    • 2010
  • The potential offered by the thermo-mechanical properties of shape memory alloys (SMA) in structural engineering applications has been the topic of many research studies during the last two decades. The main issues concern the long-term predictability of the material behaviour and the fatigue lifetime of the macro structural elements (as different from the one of wire segments). The laboratory tests reported in this paper are carried out on bar specimens and they were planned in order to pursue two objectives. First, the creep phenomenon is investigated for two different alloys, a classical Ni-Ti alloy and a Cu-based alloy. The attention is then focused on the Cu-based alloy only and its fatigue characteristics at given temperatures are investigated. Stress and thermal cycles are alternated to detect any path dependency.

Growth Stimulation of In Vitro Shoots by the Post-supplying of Liquid Medium in Anthurium andreanum ′Atlanta′ (액체배지 첨가에 의한 Anthurium andreanum ′Atlanta′의 기내생육 촉진)

  • Han, Bong-Hee;Goo, Dae-Hoe;
    • Journal of Plant Biotechnology
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    • v.30 no.2
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    • pp.185-188
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    • 2003
  • In order to enhance shoot elongation and rooting of Anthurium andreanum 'Atlanta' in vitro, 15mL of liquid media containing various concentrations of activated charcoal, sucrose and MS salts were added in same vessels after small shoots were induced from the calli on mudium supplemented with 10.0mg/L BA and 0.1mg/L 2.4-D. The post-supplying of 15mL liquid medium containing MS macro and micro elements, 30g/L sucrose and 5.0∼10.0g/L activated charcoal was significantly stimulated the shoot elongation and rooting of regenerated shoots from calli. The medium addition was also resulted in the enhanced soil survival, elongation and rooting of plantlets in cultural soil mixed with perlite and vermiculite(1 : 1)

Local Buckling Behavior of Pultruded Structural Flexural Members (펄트루젼 구조용 휨부재의 국부좌굴 거동)

  • 정재호;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.147-151
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    • 2003
  • In this study, we discussed the local buckling behavior of pultruded structural flexural members. Previous works were briefly reviewed and the local buckling behavior of orthotropic box-shape flexural members was discussed. The simplified form of equation for finding the width ratio of plate element of box-shape flexural members in which all plate components buckle simultaneously was proposed and the macro flow-chart for finding local buckling strength of pultruded flexural members was also suggested. To establish the design guide line for the local buckling of pultruded flexural members, further studies need to be performed as follows; the simplified form of solutions for finding the minimum buckling coefficient of orthotropic plate with various loading and boundary conditions including rotationally restrained boundary conditions, the simplified form of equation for calculating the coefficient of restraint provided by the adjacent plate elements.

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