• Structural Engineering and Mechanics
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• 제62권5호
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• pp.643-649
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• 2017

Masonry walls are amongst the oldest building systems. A large portion of the research on these structures focuses on the load-bearing walls. Numerical methods have been generally used in modelling load-bearing walls during recent years. In this context, macro and micro modelling techniques emerge as widely accepted techniques. Micro modelling is used to investigate the local behaviour of load-bearing walls in detail whereas macro modelling is used to investigate the general behaviour of masonry buildings. The main objective of this study is to investigate the elastic behaviour of the load- bearing walls in masonry buildings by using micro modelling technique. In order to do this the brick and mortar units of the masonry walls are modelled by the combination of plane truss elements and plane frame elements with no shear deformations. The model used in this study has fewer unknowns then the models encountered in the references. In this study the vertical frame elements have equivalent elasticity modulus and moment of inertia which are calculated by the developed software. Under in-plane static loads the elastic displacements of the masonry walls, which are encountered in literature, are calculated by the developed software, where brick units are modelled by plane frame elements, horizontal joints are modelled by vertical frame elements and vertical joints are modelled by horizontal plane truss elements. The calculated results are compatible with those given in the references.

• 터널과지하공간
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• 제24권2호
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• pp.131-142
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• 2014

본 연구는 정확한 단차부여가 가능한 전자뇌관을 사용하여, 모델링을 통한 진동예측과 실제 발파진동의 결과를 상호 비교함으로써 발파 작업 시 발생하는 진동을 예측하고 설계에 반영할 수 있는지의 가능성을 연구하였다. 모델링의 회귀분석 결과와 실제 획득한 진동 데이터의 회귀분석 결과를 비교하여 볼 때 유사성이 있는 것으로 확인되었고, 따라서 다양한 조건에서의 진동 추정이 보다 정밀성을 가질 수 있을 것으로 기대된다.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.871-888
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• 2012

This paper aims at presenting the state of the art, the recent progress, and the perspective for the future, in the modelling of two-phase flow in the horizontal legs of a PWR. All phenomena relevant for safety analysis are listed first. The selection of the modelling approach for system codes is then discussed, including the number of fluids or fields, the space and time resolution, and the use of flow regime maps. The classical two-fluid six-equation one-pressure model as it is implemented in the CATHARE code is then presented and its properties are described. It is shown that the axial effects of gravity forces may be correctly taken into account even in the case of change of the cross section area or of the pipe orientation. It is also shown that it can predict both fluvial and torrential flow with a possible hydraulic jump. Since phase stratification plays a dominant role, the Kelvin-Helmholtz instability and the stability of bubbly flow regime are discussed. A transition criterion based on a stability analysis of shallow water waves may be used to predict the Kelvin-Helmholtz instability. Recent experimental data obtained in the METERO test facility are analysed to model the transition from a bubbly to stratified flow regime. Finally, perspectives for further improvement of the modelling are drawn including dynamic modelling of turbulence and interfacial area and multi-field models.

• 한국통신학회논문지
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• 제21권9호
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• pp.2328-2340
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• 1996

Until now, the transmission of data for VOD(Video on Demenad) was based on a real time modelling of video data. Markow Modulated Fluid Sources(MMFS) and Markow Modulated Poisson Sources(MMPS) are the most widely used modelling methods. But the charactersitics of the VBR(Variable Bit Rate) signal prevents modelling from actually being "real-time". Also these methods call for the use of large buffers for the abolishment of cell loss. These modelling methods are, of course, useful i case of teleconferences where a real time modelling of video traffic is inevitable, but they are insufficient in cases where the characteristic infomation of video traffic can be obtained beforehand-cases such as VOD. Video data is speial in that if one file is preprocessed all other products can simply be copied from that onepreprocessed file. This characteristic helps reduce the overhead arising from the job of drawing out characteristic information to almost zero. But still, compared to the existing real time modelling method data transmission using characteristic information succeeds in raising the efficiency of data transmission. In tis paper we will outline a method of dta transmission which use the characteristic information of each video stream, and evaluate this method through some experiments.periments.

• 한국가구학회지
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• 제22권4호
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• pp.323-329
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• 2011

In our country, domestic species can not be used as a structural member because we have not yet grading system. So, to utilize as a basic data of grading system, bending test and numerical modelling on structural member were conducted in this study. 35 of Douglas-fir, 2" ${\times}$ 6", span 2.4 m were tested for the bending properties, and Ansys software was used to analyze the numerical modelling on the structural members. The data of knots were inspected and applied in numerical modelling. To obtain the accuracy of analysis, nonlinear numerical analysis was carried out instead of linear numerical analysis. Ultimate load had a wide range from 4883N to 11,738 N, and maximum deformation also had a range from 26 mm to 68 mm. Average of ultimate load was 8,616 N, and that of maximum deformation was 48 mm. The distinctive features of failure types were simple tension type and cross-grain tension type. Ulitmate load and maximum deformation from numerical modelling were 7,504 N and 37 mm. The numerical modelling drawn by this study is available to all species, and reasonable prediction on the bending performance is possible with only some material properties.

• Advances in Computational Design
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• 제7권3호
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• pp.173-188
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• 2022

In modern buildings, glass is considered a structurally unsafe material due to its brittleness and unpredictable failure behavior. The possible use of structural glass elements (i.e., floors, beams and columns) is generally prevented by its poor tensile strength and a frequent occurrence of brittle failures. In this study an innovative modelling based on an equivalent thickness concept of laminated glass beam reinforced with FRP (Fiber Reinforced Polymer) composite material and of glass plates punched is presented. In particular, the novel numerical modelling applied to an embedding Carbon FRP-rod in the interlayer of a laminated structural glass beam is considered in order to increase both its failure strength, together with its post-failure strength and ductility. The proposed equivalent modelling of different specimens enables us to carefully evaluate the effects of this reinforcement. Both the responses of the reinforced beam and un-reinforced one are evaluated, and the corresponding results are compared and discussed. A novel equivalent modelling for reinforced glass beams using FRP composites is presented for FEM analyses in modern material components and proved estimations of the expected performance are provided. Moreover, the new suggested numerical analysis is also applied to laminated glass plates with wide holes at both ends for the technological reasons necessary to connect a glass beam to a structure. Obtained results are compared with an integer specimen. Experimental considerations are reported.

• Coupled systems mechanics
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• 제11권2호
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• pp.121-132
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• 2022

Wastewater treatment plants (WWTPs) are designed and built to remove contaminants from wastewater. WWTPs are composed of various facilities equipped with hydro-mechanical and electrical equipment. This paper presents a comparison of two different approaches for WWTPs modelling. Static modelling is suitable for determining the dimensions of facilities and equipment capacity. The special significance of this approach is for the design of new plants, i.e., when a very small number of input data on the quantities and composition of the influent wastewater is available. Dynamic modelling is expensive, time consuming and requires great expertise in the use of simulators, models and very good understanding of the treatment processes. Also, dynamic modelling is very important to use for optimization, consideration of future scenarios and also possible scenarios on the plant. The comparison of two approaches was made on the input data from the biggest and most important plant in Bosnia and Herzegovina (B&H)-WWTP Butila (Sarajevo). The main idea is to show the differences between two demanding accesses. It is important to know how to apply an adequate approach to research and solve the set task. The II phase of the plant Butila, which includes the removal of nutrients, is planned in several years and therefore the importance of research has increased.

• 한국정보통신학회논문지
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• 제24권2호
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• pp.304-310
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• 2020

본 연구는 레이저스캐닝과 포토그래메트리 소프트웨어를 이용한 3D모델링과 실제 수목 사이의 재현 특성(수형, 질감, 세부 치수)을 비교분석하여 그 활용성을 밝히는데 있다. 연구 방법은 포토그래메트리(Pix4d)와 3D스캐너(Faro S350)를 이용하여 향나무를 3D모델링으로 재현하였다. 연구 결과 3D스캐닝과 포토그래메트리 모두 높은 재현성을 보였다. 특히 원거리에서 UAVs로 촬영한 포토그래메트리에 비해, 3D스캐닝 기술은 수피와 잎의 재현에 있어 매우 우수한 결과를 보였다. 수목의 세부 치수를 비교한 결과, 실제 수목과 3D스캐닝 사이의 오차는 1.7~2.2%로 스캐닝 결과가 실제 수목보다 크게 나타났으며, 실제 수목과 포토그래메트리 사이의 오차는 0.2~0.5%로 포토그래메트리에 의한 모델링이 실제 수목보다 크게 측정되었다. 본 연구는 수목의 가상 3D모델링 구현특성을 살핌으로써, 향후 BIM을 위한 조경수목 DB 구축, 증강현실 연계 조경 설계 및 경관 분석, 노거수의 보전 등의 활용을 위한 기초 연구로서 의의를 가진다.

• 한국학교수학회논문집
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• 제14권4호
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• pp.423-442
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• 2011

연구의 목적은 ICME(2008,Mexico) 모델링 TSG21에서 논의한 모델일의 두 과제 설정 MMa, MeA이 학교수학에 효율적으로 적용이 될 수 있는지를 알아보는데 있다. 이 실험에서 수학과 교육과정에 적용할 수 있는 몇 가지 중요한 점을 발견했는데, 첫째는 MMa집단이 통제집단 IPS에 모델링 문항에서 성취도에 우의미한 차이를 보였고, 정보처리 문항에서도 좋은 성취수준을 보였다. 다시 말하면 모델링 MMa, MeA 교육이 가능하게 현행 학교 문제 해결 또는 개념 학습에 포함이 되고 더욱 발전 되는 시스템을 가질 수 있다. 둘째는 실험집단의 학생들이 생성한 모델링 처음 3단계 상황분석, 수학질문 구성, 모델설정에서 독특한 발견전략을 사용하였고 후반 2단계에서도 전통적 IPS 문제해결과 좋은 연결성을 보였다. 또, 실험집단 MMa, MeA 학생들이 개념적 시스템의 구성과정을 잘 이해했으며 Lesh & Sriraman(2005a, 2005b)의 개념적 시스템의 구성을 뒷받침 해 주었다. 셋째는 과제설정 MMa, MeA 간에 모델링의 사고행동인 수학적 상황 센스를 만들기(S), 창조하기(C), 확장하기(E), 재정의하기(RF)가 교실에서 활발하게 일어났다는 점이다. 따라서 Pollak등이 제언한 모델링 활동은 현행 IPS 활동과 의미 있게 교류 될 수 있다.

• 한국방재안전학회논문집
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• 제10권1호
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• pp.1-10
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• 2017

근래에 들어 증가하고 있는 도심지 지반함몰 사고는 사회적 이슈가 되고 있으며 이로 인해 최근 관련 법안이 발의 되었다. 지반함몰은 수많은 원인인자들의 복합적 작용으로 발생하므로 수치해석적 기법의 적용에 한계점이 존재한다. 이로 인해 지반함몰 메커니즘 규명 연구는 주로 모형실험을 이용하여 진행되었다. 선행 연구들은 상하수도관 파열로 인한 지반함몰 모사에 초점이 맞추어져 있으며, 지하수 흐름, 지반 굴착공사 등 다양한 원인에 의해 발생하는 지반함몰에 대한 연구가 부족한 실정이다. 또한 기존 수행된 대부분의 모형실험은 1 g 상태의 모형실험이며, 지반함몰 메커니즘 평가 시 지반의 현장 구속응력을 고려할 수 없다. 따라서 본 논문에서는 모형실험을 이용한 지반함몰 거동 평가에 대한 선행 연구동향들을 고찰하여 보다 다양한 환경 조건을 모사할 수 있는 기법들에 대해 논의하였다. 또한 본 연구에서는 더 신뢰성이 있는 지반함몰 메커니즘 평가 기법으로서 원심모형실험기법을 제시하였다. 마지막으로 본 연구에서는 지반안정성평가에 지반함몰 메커니즘에서 사용한 모형실험 기법을 적용할 것을 제시했다.