• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.139-140
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• 2017

This technology employs a method of forming a single-ply PLUS waterproofing sheet layer comprised of applying a single-ply synthetic polymer layer on a vibrating structure (steel frame, RC) or an inclined surface by using a T joint lap-filling coil and an embedded metal coated sheet. The T - joint reinforcing lap-filling coil was used to block the ingress channel of the rainwater by applying the material in the vulnerable area where the three sides of the waterproof sheet overlapped. Conventional waterproofing techniques have a problem in that the waterproof sheet is pierced because the end portion of the waterproof sheet applied to the vertical portion is fixed by a nail, and the sealant applied to the end portion of the sheet cannot easily secure long-term waterproof durability due to the influence of the external environment. Therefore, the developed technology secured the waterproof durability against the vertical part by using the embedded metal sheet. In addition, automatic hot-air fusing is used to improve the quality of waterproof construction and point fixation method using fixed hardware. This is a technology that is not significantly restricted in the high degradation level regions of domestic waterproof construction environments in Korea such as low-temperature environment, wet floor.

• 대한원격탐사학회지
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• 제33권1호
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• pp.47-60
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• 2017

The permafrost active layer plays an important role in permafrost dynamics. Ecological patterns, processes, and water and ice contents in the active layer are spatially and temporally complex depending on landscape heterogeneity and local-scale variations in hydrological processes. Although there has been emerging interest in the application of optical remote sensing techniques to permafrost environments, optical sensors are significantly limited in accessing information on near surface geo-cryological conditions. The primary objective of this study was to investigate capability of L-band SAR data for monitoring spatio-temporal variability of permafrost ecosystems and underlying soil conditions. This study exploits information from different polarimetric SAR observables in relation to permafrost environmental conditions. Experimental results show that each polarimetric radar observable conveys different information on permafrost environments. In the case of the dual-pol mode, the radar observables consist of two backscattering powers and one correlation coefficient between polarimetric channels. Among them, the dual-pol scattering powers are highly sensitive to freeze/thaw transition and can discriminate grasslands or ponds in thermokarst area from other permafrost ecosystems. However, it is difficult to identify the ground conditions with dual-pol observables. Additional backscattering powers and correlation coefficients obtained from quad-pol mode help understanding seasonal variations ofradar scattering and assessing geo-cryological information on soil layers. In particular, co-pol coherences atHV-basis and circular-basis were found to be very usefultools for mapping and monitoring near surface soil properties.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.52-60
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• 2010

The stone-dust is an unavoidable by-product of aggregate production, which is produced about 0.8~1.0 million $m^3$ annually. The stone-dust is currently regarded as a hazard material on environment because it is classified as an industrial waste in the Waste Management Law of Korea. At present, the stone-dust is considered as a environmentally hazardous material, and is classified as an industrial waste according to the Waste Management Law of Korea. In this study, we assessed the heavy-metal contamination of the stone-dust on surrounding environments by various leaching tests. Leaching experiments (such as Korea Standard Leaching Procedure (KSLP), Soil Environment Preservation Act of Korea (SEPAK), Toxicity Characteristic Leaching Procedure (TCLP), and Synthetic Precipitation Leaching Procedure (SPLP)) show that very low heavy metals (As, Cd, Cu, Pb, Zn, Hg) and CN are leached out, or much less than each regulatory thresholds. The resuts of the leaching test with time in acidic solution (initial pH 5 and 3) indicate that pH-buffering minerals are present in the stone-dust. These results suggest that the stone-dust can not potentially affect adverse impact on surrounding environments such as surface water, groundwater and soil etc..

• Steel and Composite Structures
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• 제4권2호
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• pp.149-167
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• 2004

Offshore platforms have to serve in harsh environments and hence are likely to be damaged due to wave induced fatigue and environmental corrosion. Welded tubular joints in offshore platforms are most vulnerable to fatigue damage. Such damages endanger the integrity of the structure. Therefore it is all the more essential to assess the capacity of damaged structure from the point of view of its safety. Eight internally ring stiffened fatigue damaged tubular joints with nominal chord and brace diameter of 324 mm and 219 mm respectively and thickness 12 mm and 8 mm respectively were tested under axial brace compression loading to evaluate the reserve capacity of the joints. These joints had earlier been tested under fatigue loading under corrosive environments of synthetic sea water and hence they have been cracked. The extent of the damage varied from 35 to 50 per cent. One stiffened joint was also tested under axial brace tension loading. The residual strength of fatigue damaged stiffened joint tested under tension loading was observed to be less than one fourth of that tested under compression loading. It was observed in this experimental investigation that in the damaged condition, the joints possessed an in-built load-transfer mechanism. A bi-linear stress-strain model was developed in this investigation to predict the reserve capacity of the joint. This model considered the strain hardening effect. Close agreement was observed between the experimental and predicted results. The paper presents in detail the experimental investigation and the development of the analytical model to predict the reserve capacity of internally ring stiffened joints.

• 정보처리학회논문지D
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• 제16D권2호
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• pp.153-160
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• 2009

효율적인 버퍼 관리는 시스템의 성능과 밀접한 관련이 있다. 따라서 다양한 버퍼 관리 기법들에 대한 많은 연구가 진행되어 왔다. 그러나 많은 제안된 기법들의 대부분은 시간 근접성만을 고려하고 있다. 공간 데이터베이스와 같은 환경에서는 시간 근접성뿐 만 아니라, 유사한위치에 있는 공간 객체들은 서로 같이 접근 될 가능성이 높다는 공간 근접성도 존재한다. 따라서, 본 논문에서는 공간 데이터베이스 환경에서 시간근접성과 공간 근접성을 같이 효과적으로 고려하는 버퍼 관리 기법인BEAT를 제안한다. 실제 데이터와 가상 데이터를 이용한 실험 결과는 BEAT의 효율성을 보인다.

• 한국통신학회논문지
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• 제28권1C호
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• pp.81-89
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• 2003

전술통신 환경에서 MELP 보코더의 잡음에 대한 성능을 개선시키기 위해 전단에는 음향잡음억제기를, 그리고 채널과 접면에는 FEC 코드를 설치한 개선된 MELP 보코더를 제안한다. 여기서 음향잡음억제기는 IS-127 EVRC의 잡음억제 알고리즘을 MELP 보코더에 정합시켜 구현한 것이고, 채널오류 정정기는 recursive convolution 방식의 rate 1/3 인코딩 및 BCJR-MAP 디코딩 알고리즘을 근간으로 구현된 turbo 코드를 사용한다. 성능실험 결과 제안 시스템은 음향잡음 환경에서 SNR이 낮아질수록 잡음 억제 효과가 증가된다. 또한 비정체성 잡음 보다 정체성 잡음에서 더 나은 성능을 나타내며, 원래 MELP 보코더 보다 MOS가 0.24 정도 개선된다. 채널잡음 환경에서는 채널오류 정정기의 인터리버가 MELP 프레임 한 개 크기일 때 채널 비트 SNR 4.2 ㏈에서 BER 10-6이 달성된다. 디코딩 반복횟수는 3회 정도가 복잡도 대비 성능 측면에서 최적으로 판단된다. 또한 인터리버가 MELP 프레임 한 개 크기이고 디코딩 반복횟수가 3회 이상인 경우 채널 비트 SNR 2 ㏈에서 MOS 2.5 이상의 합성음질이 실현된다.

• 한국광물학회지
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• 제5권2호
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• pp.61-71
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• 1992

화산 유리질 암석인 진주암을 대상으로 60-150${\circ}C$의 온도 범위에서 다양한 농도의 알칼리 용액으로 수열 처리하므로서, 유리질 성분의 변질 양상 및 제올라이트의 합성 과정을 폐쇄계의 조건에서 연구하였다. 진주암을 속성 기원 제올라이트의 생성 환경에 해당되는 80${\circ}C$ 및 pH=8-12의 조건에서 100일간 처리하여도, 양간의 단순 용해 양상이 인지될 뿐 제올라이트는 합성되지 않았다. 여기서 처리 용액의 pH가 증가함에 따라, Si과 Al의 농도는 점진적으로 증가되지만 Si/Al의 농도비는 감소하는 경향을 나타내었다. 진주암을 0.1M 이상의 NaOH 용액으로 수열 처리하여 Na-P, 아날심, 체바자이트, Na-X와 같은 제올라이트를 합성하였다. 대개 100${\circ}C$를 경계로 60-100${\circ}C$의 온도 범위에서 Na-P, 그리고 100-150${\circ}C$에서 아날심이 주로 합성되었다. Na-P의 합성 과정에서 시료에 대한 용액의 혼합 조성비가 낮은 경우(<10ml/g)에 체바자이트, 그리고 처리 용액의 NaOH 농도가 높을 경우 (>3M)에 Na-X가 Na-P에 수반되어 생성되는 양상을 볼 수 있다. 제올라이트 합성 과정에 있어서 진주암질 유리의 알칼리 용액에 의한 변질은 화산 유리의 속성 변질에 의한 천연 제올라이트 생성 과정과 같은 용해${\cdot}$변질 반응(incongruent dissolution)의 형식으로 진행되는 것으로 해석된다. 그러나 반응 속도론적인 측면에서 보면, 이 실험으로부터 도출된 제올라이트의 합성 조건들은 화산 유리의 속성 변질에 의한 천연 제올라이트 생성 조건의 해석에 직접 적용될 수 없을 것으로 생각된다.

• 한국버섯학회지
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• 제14권2호
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• pp.51-58
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• 2016

Basidiomycetous fungi are one of the most potent biodegraders because many of its species grow on dead wood or litter, in environments rich in lignocellulose. For the degradation of lignocellulose, basidiomycetes utilize their lignocellulytic enzymes, which typically include laccase (EC 1.10.3.2), lignin peroxidase (EC 1.11.1.14), xylanase (EC 3.2.1.8), and cellulase (EC 3.2.1.4). In recent years, the practical applications of basidiomycetes have ranged from the textile to the pulp and paper industries, and from food applications to bioremediation processes and industrial enzymatic saccharification of biomass. Recently, spent mushroom substrates of edible mushrooms have been used as sources of bulk enzymes to decolorize synthetic dyes in textile wastewater. In this review, the occurrence, mode of action, general properties, and production of lignocellulytic enzymes from mushroom species will be discussed. We will also discuss the potential applications of these enzymes.

• 한국CDE학회논문집
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• 제4권1호
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• pp.12-18
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• 1999

A deformable non-Uniform Rational B-Spline (NURBS) based volume is programed for the force reflecting exoskeleton haptic device. In this work, a direct free form deformation (DFFD) technique is applied for the realistic manipulation. In order to implement the real-time deformation, a nodal mapping technique is used to connect points on the virtual object with the NURBS volume. This geometric modeling technique is ideally incorporated with the force reflecting haptic device as a virtual interface. The results in this work introduce details for the complete set-up for the realistic virtual clay modeling task with force feedback. The force reflecting exoskeleton haptic manipulator, coupled with a supporting PUMA 560 manipulator and the virtual clay model are integrated with the graphics display, and results show that the force feedback from the realistic physically based virtual environment can greately enhance the sense of immersion.

• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1037-1051
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• 2018

The genus Rhodococcus is a phylogenetically and catabolically diverse group that has been isolated from diverse environments, including polar and alpine regions, for its versatile ability to degrade a wide variety of natural and synthetic organic compounds. Their metabolic capacity and diversity result from their diverse catabolic genes, which are believed to be obtained through frequent recombination events mediated by large catabolic plasmids. Many rhodococci have been used commercially for the biodegradation of environmental pollutants and for the biocatalytic production of high-value chemicals from low-value materials. Recent studies of their physiology, metabolism, and genome have broadened our knowledge regarding the diverse biotechnological applications that exploit their catabolic enzymes and pathways.