• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.15-23
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• 2021

In this paper, service life for RC(Reinforced Concrete) substructure subjective to carbonation was evaluated through deterministic and probabilistic method considering field investigation data and Design Code(KDS 14 20 40). Furthermore changes in service life with increasing COV(Coefficient of Variation) and equivalent safety index meeting the same service life were studied. From the investigation, the mean and its COV of cover depth were evaluated to 70.0 ~ 90.0 mm and 0.2, respectively. With intended failure probability of 10.0 % and 70 mm of cover depth, service life decreased to 137 years, 123 years, and 91 years with increasing COV of 0.05, 0.1, and 0.2, respectively. In the case of 80 mm of cover depth, it changes to 179 years, 161 years, and 120 years with increasing COV. The equivalent safety index meeting the same service life from deterministic method showed 1.66 ~ 3.43 for 70 mm of cover depth and 1.61 ~ 3.24 for 80 mm of cover depth, respectively. The various design parameters covering local environment and quality condition in deterministic method yields a considerable difference of service life, so that determination of design parameters are required for exposure conditions and parameter variation.

• Korean Institute of Interior Design Journal
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• no.16
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• pp.168-174
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• 1998

In the Western Civilization you can clearly see the change in the architectural system. In the 19th Century many of arcitectural style resurrected in the appearance of style revival. And each of the Style's appropriateness and exactness were very complicatedly discussed. After the middle of 19th Century a series of morality movement which showed an expectation for a historical revival started to show declining atmosphere. To architects at the periods more universal formation seeking and new surpassing style pursuing logic has exacted which care from very different from the past During this period a question were brought up about architecture ornamental rightness and appropriateness. As each of the architects had a saying about the ornament was recognized as important part of architect. On this bases this study's purpose is finding out whst is the maeaning and content of G.Semper's "Bekleidungstheorie"

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.407-408
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• 2019

토지 피복과 관련된 지표면 파라미터는 일반적으로 지표에서 감지되어 위성영상에 나타난 많은 물리적 프로세스에 의존하며 계절적 주기성을 갖는 시간적 변화를 보인다. 하모닉 모형은 복잡한 파형을 정현파 성분의 합으로 표시함으로써 레벨, 주기, 진폭 및 위상 요소를 통한 변동을 분석함으로써 표면에서 관찰되는 계절적 변화 패턴을 모델링하는 데 적합한 모형이다. 본 연구에서는 MODIS NDVI (Normalized Difference Vegetation Index) 시계열 자료를 이용하여 하모닉 패턴의 특성에 따라 토지 피복을 분류하는 방법론을 제안하였다.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1771-1777
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• 2023

With the advancements of deep learning, many semantic segmentation-based methods for land cover classification have been proposed. However, existing deep learning-based models only use image information and cannot guarantee spatiotemporal consistency. In this study, we propose a land cover classification model using geographical coordinates. First, the coordinate features are extracted through the Coordinate Hash Encoder, which is an extension of the Multi-resolution Hash Encoder, an implicit neural representation technique, to the longitude-latitude coordinate system. Next, we propose an architecture that combines the extracted coordinate features with different levels of U-net decoder. Experimental results show that the proposed method improves the mean intersection over union by about 32% and improves the spatiotemporal consistency.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1089-1100
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• 2017

This paper presented a method using past land cover maps in image segmentation and training set collection for updating land cover maps. In this method, the object boundaries in past land cover maps were used for segmenting image clearly. Also, the classes of past land cover maps were used to extract additional informative training set from the initial classification result using a small number of initial training set. To evaluate the applicability of proposed method, a case study for updating land cover maps was carried out using middle-level land cover maps and WorldView-2 image in the Taean-gun, South Korea. As a result of the case study, the confusions between urban and barren, paddy/dry field and grassland in the initial classification result were reduced by adding training set. In addition, the object segmentation using boundaries of past land cover map cleared land cover boundaries and improved classification accuracy. Based on the result of case study, the proposed method using past land cover maps is expected to be useful for updating land cover maps.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.423-423
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• 2023

습지 생태계는 탄소저장고, 대기 온·습도 조절 등의 기능을 수행하는 만큼 면밀한 관리가 요구된다. 습지의 규모와 생태계는 밀접한 연관성을 가지므로 그 규모를 우선적으로 파악할 필요가 있으며, 이를 위해 지표면의 상태를 산지, 습지, 수역 등의 항목으로 구분한 토지피복지도가 고려될 수 있다. 현재, 환경부에서 운영 중인 환경공간정보서비스(https://egis.me.go.kr/)에서는 각각 30 m, 5 m, 1 m의 공간 해상도와 7, 22, 41가지 분류 항목을 갖는 대분류, 중분류, 세분류로 구분된 토지피복지도를 제공하며 이러한 자료들은 모두 1년 이상의 시간 해상도를 갖는다. 습지의 경우, 계절에 따른 환경 변화로 인한 규모의 변동성이 크게 나타날 수 있기 때문에 1년 이하의 시간 해상도를 갖는 고품질 토지피복 분류 정보가 요구된다. 따라서 본 연구에서는 기존 자료의 낮은 시간 해상도 보완을 목표로, 1개월과 30 m의 시·공간 해상도를 갖는 토지피복지도를 구축하기 위한 방법론을 제안하고자 한다. 이를 위해 Landsat-8 등과 같은 다양한 인공위성 자료를 수집하고, Support Vector Machine 등과 같은 머신러닝 기법을 적용하였다. 최종적으로 습지보전법에서 지정한 습지보호지역 중 내륙습지 26개소를 대상으로, 본 연구로부터 산출된 토지피복지도를 기존 환경공간정보서비스 내 대분류 토지피복지도와 비교·평가하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.65-72
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• 2016

Service life evaluation for RC Structures exposed to chloride attack is very important, however the previous two methods(deterministic and probabilistic method) show a big difference. The paper presents a service life simulation using deterministic and probabilistic method with time-dependent diffusion coefficient. Three different cases are considered for diffusion coefficient, concrete cover depth, and surface chloride content respectively, and then the PDF(probability of durability failure) and the related service life are obtained. Through adopting time-dependent diffusion, the discrepancy between the two methods can be reduced, which yields reasonable service life. When diffusion coefficient increases from $2.5{\times}10^{-12}m^2/sec$ to $7.5{\times}10^{-12}m^2/sec$, the service life decreases to 25.5~35.6% level, and cover depth does from 75 mm to 125 mm, it increases to 267~311% level as well. In the case of surface chloride content from $5.0kg/m^3$ to $15.0kg/m^3$, it changes to 40.9~54.5%. The effect of cover depth is higher than the others by 8~10 times and also implies it is a key parameter to service life extension.

• Korean Institute of Interior Design Journal
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• v.23 no.3
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• pp.29-38
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• 2014

This paper is to analysis covering and exposing elements through surface in the spirit of the time through the meaning of relationship between structure and symbol(ornament) in the theory of dressing of Gottfrid Semper. In other words, The purpose is to illuminate how complementary tectonic between structure and symbolic of an architecture surface is expressed in accordance with the biased required conditions relating with the paradigm of the era. The advancement of the new method of tectonic and the new aesthetic taste have a deep relation with the reconsidering the dichotomy classification discussing a dominant position between structure and symbol(ornament). Expression of surface representing the era comes across the combined interpretation of technology, structure, and the non-physical culture's art of the community and the era.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.365-367
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• 2008

원자로 냉각계통의 압력경계를 구성하고 있는 재료들의 부식은 재료 표면에 형성되는 산화막, 금속재료의 구성성분이 용해되어 생성된 가용성 화학종 및 산화물 입자 형태의 부식생성물들을 발생시킨다. 금속합금의 부식에 의한 가용성 화학종 및 입자들의 방출은 원자로 냉각계통에서 노심과 증기발생기를 순환하면서 연료피복관 위에 침전되어 여러 가지 문제를 야기한다. 크러드는 구조재료의 부식에 기인하여 발생한 부식생성물들이 냉각수에 부유하여 떠다니거나 피복관 표면에 침적하여 형성되며 주로 니켈과 철 산화물로 구성되어 있다. 원자로 냉각계통에서 크러드를 최소화하기 위하여 수화학 조건들을 제어하지만 장주기 고연소도 노심에서 AOA 현상을 일으키는 주된 원인이 되고 있다. 피복관 위에 침적되는 크러드는 붕소의 잠복위치를 제공할 뿐만 아니라 냉각수의 압력강하를 증가시키고 피복관의 부식 및 파손 원인을 제공하며 방사선 준위가 증가하도록 한다. 따라서 본 연구에서는 반응속도론적 관점에서 원자로 정지시의 용출 크러드 특성에 대한 연구를 수행하였다.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.445-452
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• 1994

Three-axial deformation behavior of the Zircaloy cladding tube under the irradiation condition of the fuel in pressurized water reactor can be analyzed by the anisotropy in the creep and the irra- diation growth, which depends on the texture parameter. A methodology to evaluate the impact of the anisotropic creep and irradiation growth on the strain in each axial direction of the cladding tube has been proposed. Based on the measured strains after irradiation and predicted ones with the help of a fuel performance analysis code, it is found that a tangential strain of the cladding tube is caused mainly by the creep, whereas a axial strain of the cladding is caused mainly by the irradiation growth but with a considerable contribution of the creep at low irradiation.