• 한국지리정보학회지
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• 제8권2호
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• pp.10-20
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• 2005

본 연구에서는 최소차하천의 임계값에 따른 지형매개변수의 변화특성을 분석하였다. 분석을 위하여 금호강 중류의 금호수위표지점 상류 유역을 대상으로 하였다. 분석에서는 유역내의 1:25,000 수치지형도를 $10{\times}10m$ 격자망으로 구성하여 이용하였다. 지형매개변수의 분석 범위로는 하천차수별 개수, 유로연장, 면적, 경사, 기복도, 만곡도, 배수밀도 및 전 유역에 대한 유로연장, 총 하천의 길이 등을 대상으로 하였다. 분석 결과로 볼 때, 최소차 하천의 임계값 설정이 유역의 지형 매개변수에 매우 큰 영향을 미치고 있음을 알 수 있었다. 최소하천 임계 면적은 $0.10km^2$을 기준으로 하여 매개변수간에 큰 변동을 보이고 있으나 그 이상에서는 변동폭이 매우 작음을 알 수 있었다.

• 디지털융복합연구
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• 제13권10호
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• pp.327-335
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• 2015

재난통신망은 TETRA(TErrestrial Trunked RAdio)에서 대용량 데이터 통신이 가능한 광대역 이동통신 기술인 Public Safety-LTE(Long Term Evolution) 자가망을 활용하는 방향으로 발전하고 있다. 국내에서는 재난재해 대응기관 간의 일원화된 통신체계 유지를 위해 재난안전통신망 구축사업을 추진하고 있으나, 재난재해 현장에 위치한 피해당사자와의 통신을 고려하지 않고 재난재해 대응기관 간 지휘통제를 중심으로 통신망을 구축하고 있다. 본 연구에서는 국내 재난통신망 구축동향과 해외 선진사례를 해석하여 전 범위 재난통신망 구축을 위한 쟁점을 도출하고 통신주체와 목적에 따라 재난통신 영역을 새롭게 정의하여 재난통신 영역을 통제통신, 대응통신, 현장통신, 당사자통신, 경보통신으로 세분화하였다. 본 연구를 통하여 재정의 된 재난통신 영역의 특성을 분석하고 이에 따른 핵심 품질요건을 재설계하여 영역별 음영지역 없는 전 범위 재난통신 체계 구축방안을 수립하였다.

• 한국건축시공학회지
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• 제4권1호
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• pp.89-96
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• 2004

Porous concrete is used of various parts by advantage of porous. Example of growing of plant is possible, and dwelling of creature, and filter functions of various contaminant, and decrease of noise, and so on. This research is for porous concretes that were used by four aggregate rubble, refreshing aggregate, expanded clay, orchid stone. This research estimate that physical and mechanical characteristics of fresh concrete and hardened concrete. The purpose of this research is to make environment-friendly porous concrete. This research's conclusion is as following : 1. Porous Concrete's slump was measured 12~14cm with rubble, 12~16cm with refreshing aggregate, 11~13cm with expanded clay, 11~13cm with orchid stone. Weight of aggregate was bigger, slump price appeared by bigger thing. Because placed Porous Concrete is low viscosity and small resistance between aggregate, it estimated that have high workability. 2. Porous Concrete's unit weight was measured 1.71~1.75t/$\textrm{m}^3$ with rubble, 1.58~1.62t/$\textrm{m}^3$ with refreshing aggregate, 1.19~1.20t/$\textrm{m}^3$ with expanded clay, 0.98~1.06t/$\textrm{m}^3$ with orchid stone. Showed aspect such as weight of aggregate. 3. Porous Concrete's compressive strength was measured 76~102kgf/$\textrm{cm}^2$ with rubble, 51~60kgf/$\textrm{cm}^2$ with refreshing aggregate, 30~40kgf/$\textrm{cm}^2$ with expanded clay, 13~16kgf/$\textrm{cm}^2$ with orchid stone. 4. Tendency of tensile strength and bending strength showed generally similarly with compressive strength, but showed low value fewer than 15kgf/$\textrm{cm}^2$ Therefore, wire mesh, reinforcing rod, such as establishment of frame is considered to need in reinforcement about tensility or flexures in case receive tensility or produce product of thin absence form. It concludes by speculating on the consequences of extrapolating the results of study to remodelling the office building being already existence.

• 한국건설순환자원학회논문집
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• 제10권1호
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• pp.66-73
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• 2022

동절기 콘크리트 포장체의 블랙아이스 발생위험을 낮추고 동결에 의한손상을 방지할 목적으로 콘크리트의 전도저항성을 활용하여 자기 히팅 콘크리트를 개발하고자 하였다. 이를 위하여 분말형과 액상형 폐CNT와 전도촉진을 위해 폐음극재를 사용하여 강도변화와 온도 발열특성을 평가하고자 하였다. 액상형 폐CNT가 모르타르내에서 분산정도가 효과적이고, 강도저하가 작게 발생하는 것으로 분석되었다. 또한 모르타르에 스틸매쉬, 구리포일과 구리선을 전극으로 적용하여 DC 24 V를 공급하였으며, 폐CNT, 폐음극재과 탄소섬유 혼입율에 따른 온도변화 특성을 평가하였다. 또한 선정된 최적배합으로부터 전극간격에 따른 온도 특성을 평가하여 AC 50 V 까지는 전극간격 100 mm 까지는 충분한 발열 특성을 갖는 것을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제27권8호
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• pp.135-142
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• 2022

본 논문에서는 위급한 상황(예 : COVID-19)에서 바이러스 검사를 빠르게 진행하기 위한 그래프 기반 사용자 경로 제어와 이것을 도시 맵에서 시뮬레이션을 할 수 있는 프레임워크를 제안한다. 가상환경에서 많이 활용되는 길찾기(Pathfinding) 알고리즘인 A^*나 네비게이션 메쉬 자료구조는 정해진 정적 이동 경로만을 안내하기 때문에 가상환경에서 에이전트를 제어하는 CS(Computer science)문제에 적용할 할 경우 효율적이다. 하지만, 실제 COVID-19 환경에 적용하여 문제를 풀기에는 충분하지 않다. 특히, 빠른 바이러스 검사를 받기 위해서는 짧은 거리만을 이용하는 게 아닌, 실제 도로 교통상황, 병원의 크기, 환자 이동 수, 환자 처리 시간 등 고려해야 할 상황들이 많다. 본 논문에서는 위에서 언급한 다양한 속성들과 이를 이용한 최적화 함수를 모델링하여, 실제 도시 맵에서 바이러스 검사를 빠르고 효율적으로 처리할 수 있고, 다양한 상황을 디지털 트윈 방식으로 시뮬레이션을 할 수 있는 프레임워크를 제안한다.

• Coupled systems mechanics
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• 제11권5호
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• pp.439-458
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• 2022

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-Of-Freedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.279-286
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• 2013

This paper introduces a new method for identification of building energy performance problems. The presented method is based on automated analysis and visualization of deviations between actual and expected energy performance of the building using EPAR (Energy Performance Augmented Reality) models. For generating EPAR models, during building inspections, energy auditors collect a large number of digital and thermal imagery using a consumer-level single thermal camera that has a built-in digital lens. Based on a pipeline of image-based 3D reconstruction algorithms built on GPU and multi-core CPU architecture, 3D geometrical and thermal point cloud models of the building under inspection are automatically generated and integrated. Then, the resulting actual 3D spatio-thermal model and the expected energy performance model simulated using computational fluid dynamics (CFD) analysis are superimposed within an augmented reality environment. Based on the resulting EPAR models which jointly visualize the actual and expected energy performance of the building under inspection, two new algorithms are introduced for quick and reliable identification of potential performance problems: 1) 3D thermal mesh modeling using k-d trees and nearest neighbor searching to automate calculation of temperature deviations; and 2) automated visualization of performance deviations using a metaphor based on traffic light colors. The proposed EPAR v2.0 modeling method is validated on several interior locations of a residential building and an instructional facility. Our empirical observations show that the automated energy performance analysis using EPAR models enables performance deviations to be rapidly and accurately identified. The visualization of performance deviations in 3D enables auditors to easily identify potential building performance problems. Rather than manually analyzing thermal imagery, auditors can focus on other important tasks such as evaluating possible remedial alternatives.

• Coupled systems mechanics
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• 제12권6호
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• pp.481-501
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• 2023

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-OfFreedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• 풍력에너지저널
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• 제15권1호
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• pp.91-102
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• 2024

Rapid progress is being made in foundational technology research and engineering for the construction of floating offshore wind farms. There is active development of technology for detachable mooring systems, which have strengths in addressing maintenance issues that arise in floating offshore wind farms and enhance their economic viability. Conventional detachable mooring systems use Kenter links inserted into the middle of mooring chains, which require excessive time for retrieval by Anchor Handling Tug Supply (AHTS) vessels during detachment operations. Moreover, these operations pose risks of link damage and accidents. Therefore, there is a demand for the development of a new concept of detachable mooring systems. The proposed detachable mooring system in this study simultaneously integrates a fairlead chain stoppers (FCS) and submersible mooring pulleys (SMP), which enables all operations to be conducted on the AHTS vessel without underwater tasks. This study detailed the design and safety evaluation of the SMP, a core component of the detachable mooring system, based on the minimum breaking load (MBL) of selected mooring lines according to the capacity of the floating platform. It referenced international codes (AISC Specification for Structural Steel Buildings D5, Pin-Connected Members) for design verification and performed finite element analysis to evaluate the strength of major components in installation and operation scenarios. Additionally, procedures and techniques for evaluating the structural strength of components under uncertain boundary conditions were proposed.

• 대한기계학회논문집B
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• 제26권9호
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• pp.1209-1217
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• 2002

The use of a two dimensional hierarchical elements are investigated for the incompressible flow computation. The construction of hierarchical elements are explained by both a geometric configuration and a determination of degrees of freedom. Also a systematic treatment of essential boundary values has been developed for the degrees of freedom corresponding to higher order terms. The numerical study for the poisson problem shows that the computation with hierarchical higher order elements can increase the convergence rate and accuracy of finite element solutions in more efficient manner than the use of standard first order element. for Stokes and Cavity flow cases, a mixed version of penalty function approach has been introduced in connection with the hierarchical elements. Solutions from hierarchical elements showed better resolutions with consistent trends in both mesh shapes and the order of elements.