• Advances in concrete construction
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• 제15권6호
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• pp.377-389
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• 2023

In this study, an improved modular arch system with the lower arch space composed of a precast arch block and an outrigger was proposed as an underground culvert, and its applicability and structural behaviors were confirmed. This modular arch culvert structure with vertical walls was designed using precast blocks and by adjusting the placement spacing of concrete blocks to the upper part form an arch shape and the lower part form a vertical wall shape, based on previously researched modular arch systems. Owing to the vertical wall of the proposed modular arch system, it is possible to secure a load-carrying capacity and an arch space that can sufficiently resist the earth pressure generated from the backfill soil and loading on the arch system. To verify the structural characteristics, and applicability of the proposed modular precast arch culvert structure, a full-scale modular culvert specimen was fabricated, and a loading test was conducted. By examining its construction process and loading test results, the applicability and constructability of the proposed structure were analyzed along with its structural characteristics. In addition, its the structural predictability and safety for the applicability were evaluated by comparing the construction process and loading test results with the FE analysis results.

• Earthquakes and Structures
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• 제27권1호
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• pp.41-55
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• 2024

There are obvious differences between the characteristics of offshore ground motion and onshore ground motion in current studies, and factors such as water layer and site conditions have great influence on the characteristics of offshore ground motion. In addition, unlike seismic response analysis of offshore superstructures such as sea-crossing bridges, tunnels are affected by offshore soil constraints, so it is necessary to consider the dynamic interaction between structure and offshore soil layer. Therefore, a seismic response analysis model considering the seawater, soil layer and tunnel structure coupling is established. Firstly, the measured offshore and different soil layers onshore ground records are input respectively, and the difference of seismic response under different types of ground motions is analyzed. Then, the models of different site conditions were input into the measured onshore bedrock strong ground motion records to study the influence of seawater layer and silt soft soil layer on the seabed and tunnel structure. The results show that the overall seismic response between the seabed and the tunnel structure is more significant when the offshore ground motion is input. The seawater layer can suppression the vertical seismic response of seabed and tunnel structure, while the slit soft soil layer can amplify the horizontal seismic response. The results will help to promote seismic wave selection of marine structures and provide reference for improving the accuracy of seismic design of immersed tunnels.

• Journal of Information Processing Systems
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• 제5권4호
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• pp.221-228
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• 2009

Due to low cost, low-power, and scalability, ZigBee is considered an efficient wireless AMR infrastructure. However, these characteristics of ZigBee can make the devices more vulnerable to unexpected error environments. In this paper, a fault-tolerant wireless AMR network (FWAMR) is proposed, which is designed to improve the robustness of the conventional ZigBee-based AMR systems by coping well with dynamic error environments. The experimental results demonstrate that the FWAMR is considerably fault-tolerant compared with the conventional ZigBee-based AMR network.

• 한국물환경학회지
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• 제29권6호
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• pp.847-851
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• 2013

This study describes the results of an investigation conducted in order to characterize the quantity and quality of individual gray water streams. The highest pollutants concentrations were found in gray water originating from kitchen and laundry with $BOD_5$ concentrations in the order of several hundreds $mgl^{-1}$. In contrast to this, bathroom was regarded as a major contributor of Escherichia coli. Laundry gray water has higher pH, sodium, sulfate, anionic surfactants. Individual gray water types had different contribution to the overall daily discharge and relative pollutants loads. Kitchen, although accounting for only 13% of the total volume, was identified as a major source of microorganisms with Total coliforms, Escherichia coli, Fecal streptococcus taking up 82%, 74% and 54% of their relative daily load, respectively. The laundry gray water, although being responsible for 36% of the total daily discharge, was established as a significant contributor of sodium, sulfate, anionic surfactants and TOC (70%, 72%, 84% and 52%, respectively). But the laundry gray water was a minor source of microorganisms. Bathroom was found to be a major gray water producer, making up 51% of the flow, but constituted less than 50% of the relative daily load in most cases.

• 한국지반공학회논문집
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• 제34권12호
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• pp.145-154
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• 2018

교량, 터널 옹벽 등의 콘크리트 구조물에서 수행되는 손상 조사 및 검사 방법은 일반적으로 검사원이 현장에서 직접 측량 도구를 사용하여 시각적으로 검사하는 방법이다. 이 방법은 검사원의 주관성에 크게 의존하기 때문에 기록의 객관성과 신뢰성이 떨어지게 된다. 따라서 균열을 자동으로 탐지하고 균열 특성을 객관적으로 분석할 수 있는 새로운 이미지분석기법이 필요하다. 본 연구에서는 콘크리트 이미지에서 균열을 검출하고 특성(균열의 길이, 폭)을 분석하기 위한 딥러닝 및 이미지분석기법을 개발하였다. 균열 검출과 해당 균열의 특성을 얻기 위해 두 가지 단계의 방법이 제안되었다. 제안된 방법의 성능을 검증하기 위하여 라벨이 있는 다양한 균열 이미지가 사용되었으며, 균열 판단과 구획화에 대해 90% 이상의 정확도를 확인하였다. 최종적으로 실제 촬영된 균열 영상의 균열 특성을 분석하고 실제 측정치와 오차를 확인하여 개발된 기법의 성능을 검증하였다.

• 한국조경학회지
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• 제32권1호
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• pp.69-79
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• 2004

This Paper examines theoretical terrains and design strategies of landscape urbanism which is an emerging hybrid field at the intersection of architecture, landscape architecture, and urbanism. Landscape urbanism offers alternative approaches for theory, education, and practice in contemporary landscape architecture. It views the emergent urban complex sites-post-industrial sites, landfill, brownfield, urban void, etc., not as a weakness, but as a strength. Landscape urbanism poses an understanding of landscape as an element of urban infrastructure. In this sense, the landscape is seen in the context of contemporary urban development and public works. As a complex amalgam, landscape urbanism is more than a design style it is an ethos, an attitude, a way of thinking and acting. We can chart the main characteristics of landscape urbanism such as horizontality and surface, infrastructure, process, technique, and ecology. Multilayered examples of landscape urbanism can be seen in several experimental practices such as worts of Rem Koolhaas, MVRDV, Adriaan Geuze/West 8, James Comer, etc. It is possible to summarize the productive strategies for landscape urbanism as follows : thickening, folding, new materials, nonprogrammed use, impermanence, and movement.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.722-726
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• 2010

Inventory survey is process collecting data about cut slope. It's different from inspection. It contains not only basic information about cut slope, especially location, GPS positioning, height, length, weathering, joint direction, water conditions but also level of danger and damage. Collected data are being used get at status about cut slope along national roads. And It helps judging about priority of detailed investigation. According to results of analysis, we found better method about maintenance of cut slope. Later on, if inventory research is finished, we will understand characteristics of collapse slopes.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.691-699
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• 2015

To evaluate the possibility of charcoal as Green Infrastructure (GI) materials, data such as moisture content, amount of adsorbed water, and amount of evaporation were collected. Some data from previous study were referenced to find out if correlations exist between results in this study and previous study. Only porosity was directly related to moisture content. Two mechanical charcoal had better abilities than traditional charcoal in all three categories. Mechanical black charcoal chips produced by National Forestry Cooperative Federation (NFCFC) adsorbed 333.3% of water in thirty minutes, 297.5% in five minutes, and evaporated around 75% water in four days. This ability is much higher than other five charcoal. Even though results of test showed various degrees and NFCFC was the best as GI materials, data of charcoal were also within acceptable range based on generally accepted characteristics of GI materials.

• International Journal of Railway
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• 제6권2호
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• pp.78-84
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• 2013

This paper is about the first experiment in Korea that was conducted on speeding increase up with rail speeds at 430km/h at high speed railway of designed 350km/h. and analysis data collected on vibration accelerations of roadbed. There are barely references on roadbed behavior measurement with rail speeds more than 350 km/h in Korea as it has never been conducted the experiment on it. So the experiments were confirmed the reliability through crosschecking the figures/values from respective sensors and measuring devices after measuring EMS and ICP types. Based on the study, values of vibration acceleration were less than 12% compared with the ones that conducted while speeding up of HEMU-430X. Also, figures of HSB for concrete bed tracks were 52% against the standard. According to the results, all the performance evaluation of vibration acceleration for roadbeds in transition zones is under the standard.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1273-1274
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• 2006

Chemically pure, hydride/dehydride titanium powders were cold pre-compacted then extruded at $850^{\circ}C$ and $\sim450MPa$ under argon. The extrusions were 100% dense with a narrow band of surface porosity and equiaxed microstructure of similar magnitude to the starting material. The tensile properties of the bars were better than conventionally extruded CP titanium bar product. Outcomes from this study have assisted in the identification of a number of key characteristics important to the extrusion of titanium from pre-compacted CP titanium powders, allowing the elimination of canning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PM processes.