• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2001.11a
• /
• pp.167-176
• /
• 2001

• Proceedings of the SAREK Conference
• /
• 2005.06a
• /
• pp.94-94
• /
• 2005

• Magazine of korean Tunnelling and Underground Space Association
• /
• v.23 no.4
• /
• pp.49-57
• /
• 2021

• Journal of the Korean Institute of Gas
• /
• v.20 no.5
• /
• pp.72-81
• /
• 2016

When the coatings of buried steel pipelines are damaged, corrosion could be occurred on the surface of the damaged areas. Moreover the pinhole occurred by corrosion of pipelines may cause accidents due to gas leakage. To prevent these accidents, foreign countries including UK and USA have carried out coating defect detection on the buried gas pipelines by using a DCVG or a ACVG and have conducted direct assessment of pipelines through digging the ground, and if necessary, have repaired the pipelines. That is called ECDA i.e External Corrosion Direct Assessment which is regulated by NACE standards(SP 0502) and etc. In Korea, the ECDA provisions were included in KGS FS551 in 2014 when the regulations of Safety Validation in Detail for the medium-pressure piping were introduced. We have developed the equipment which can be used to detect external corrosion of the buried gas pipelines. We have also constructed pipeline test bed for empirical test of the developed equipment. In addition, we have carried out the verification experiments of the developed equipment on the test bed to demonstrate the performance of the equipment. The experiments were conducted by comparison tests of the developed equipment and other equipments which have been introduced and used in Korea. As the result, we have found the developed equipment is easier to use and has far superior performance compared to other equipment being used in Korea.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.15 no.2
• /
• pp.135-149
• /
• 2017

Demonstration programs for spent nuclear fuel dry storage have been carried out to produce important and confirmatory data to support safety of dry storage systems and integrity of spent nuclear fuel stored in dry condition. The US initiated the dry storage of spent nuclear fuel and has strict and explicit regulatory stipulations on the integrity of spent nuclear fuel in dry storage. The US has carried out several notable demonstration programs for the initiation and license extension of dry storage. At the very early stage of dry storage, the demonstration programs were focused on proof of the safety of dry storage systems and a demonstration project called the dry cask storage characterization project was performed for the license extension of low burn-up fuel dry storage. Currently, a demonstration program for the license extension of high burn-up fuel dry storage is under way and is expected to continue for at least 10 years. Korea has not yet begun the dry storage of PWR fuel and the US programs can be a good reference and can provide lessons to safely begin and operate dry storage in Korea. In this paper, past and current demonstration programs of the US are analyzed and several recommendations are provided for demonstration programs for the dry storage of spent nuclear fuel in Korea.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.77-77
• /
• 2018

한국 건설기술연구원의 하천실증연구센터는 기존에 불가능했던 준 실규모 하천실험, 생태실험, 치수분야 대형 모형실험 및 하천관련 기준수립을 위한 치수분야 수요와 하천 구조물의 품질성능평가 등을 목적으로 설립된 대규모 하천실증연구센터이다. 안동 하천실증연구센터는 총면적 $193,051m^2$의 부지에 하천의 일반적인 형상을 갖고 있는 완경사, 급경사, 만곡수로가 있으며, 수리량 측정 실험을 위한 초음파 유속계, 프로펠러 유속계, 전자식 유속계 등의 유속 측정 장비를 보유하고 있고, Total Station, Lidar, RTK-GPS 등 지형 측량에 사용할 수 있는 장비들도 보유하고 있어, 하천관련 실험을 수행하기에 충분한 여건을 보유하고 있다. 하천실증연구센터는 2013년부터 내 외부활용에서 활용할 수 있도록 지원을 수행하였으며, 총 118건의 하천 수리 및 생태분야, 지반분야 등 다양한 토목분야의 연구자들이 하천실증연구센터를 방문하여 실험을 수행하였고, 국내 기관 및 대학뿐만 아니라 미국의 Iowa 대학, Idaho 대학, USGS, 네덜란드 Deltares, 프랑스 Irstea 등 외국의 대학 및 기관에서도 방문하여 실험 및 공동연구를 수행하였다. 안동 하천실증연구센터의 활용 범위와 활용 건수가 지속적으로 증가함에 따라 자체적인 검토 및 외부의 의견에 따라 센터의 실험시설에 대한 개선이 필요한 사항이 발생하게 되었다. 하천실증연구센터의 수로는 기존의 지반위에 성토를 하여 인공적으로 건설하였기 때문에 일반적인 실내의 실험수로와는 다르게 하상에서의 침투가 발생하며, 이에 따라 하류방향으로 흐름이 진행될수록 유량의 변동이 발생하게 된다. 이에 따라 침투로 인해 발생하는 유량의 변동이 하도 유량 공급의 안정화에 미치는 영향에 대한 신뢰성 검증의 필요성이 필요하다고 판단되어 펌프에서의 유량 공급 및 하도내에서의 유량 안정화에 대한 검증 실험을 수행하고자 한다. 유량 공급에 대한 검증 실험은 크게 두 단계로 구성하였다. 첫 번째 단계는 펌프의 유량 공급에 대한 검증실험을 수행하고, 두 번째 단계에서는 동일한 조건내에서 하류의 지하수 수심, 공급수조의 수심, 하도내의 수심과 ADV 및 ADCP로 측정된 유량과의 관계를 통해 하도내의 유량이 얼마나 일정하게 공급되고, 하류방향으로 갈수록 유량 손실의 경향에 대한 실험을 계획하였으며, 전체적인 실험은 장기적으로 각 수로에 대하여 수행하는 것을 목표로 하였으며, 본 실험단계에서는 완경사 수로를 대상으로 하였다.

• Fire Science and Engineering
• /
• v.20 no.4 s.64
• /
• pp.98-104
• /
• 2006

The Fire Protection Regulatory documents require the fire-resistive rating of fire barrier penetration seals be same as that of fire barriers. Pilot application of penetration seal evaluation for K nuclear plant, built before penetration seal requirements were made, was done. In this evaluation, visual inspection and estimating fire rating by comparing installed configuration with tested configuration of penetration seals, called bounding approach method, were applied. Further improvements for retrofit and maintenance are recommended with penetration seal evaluation results also. The practical use of the methodology adopted in this study and the evaluation result of K nuclear plant will be anticipated for other plant's penetration seal evaluation.

• Land and Housing Review
• /
• v.13 no.3
• /
• pp.93-106
• /
• 2022

Ventilation plays an important role in controlling indoor air quality. Due to the recent spread of infectious diseases such as COVID-19 and with people spending more time indoors, there's been increased attention on the importance of ventilation performance. In many countries, ventilation is regulated by airflow rates and the number of air changes per hour (ACH). However, airflow rates and ACH alone do not provide an accurate account of actual indoor pollutant removal and ventilation uniformity in a space. This study looked into the ventilation performance of an actual residential unit using several sampling points instead of basing it off of airflow and air change rates. Literature review was used to derive relevant influencing factors and the tracer gas dilution method was used for the field test. The study measured air velocity, age of air, and ventilation efficiency at several locations and compared them to the average value at the center of the test space to determine the differences in ventilation performance at the selected measurement points. The study showed that different sampling locations resulted in different ventilation values. Findings of this study will be used to develop an experimental procedure for evaluating indoor ventilation performance of actual residential spaces.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.177-184
• /
• 2017

Understanding trends and drivers of technology diffusion is imperative to forecast new technology adoption and understand the process of technological innovation. Our research utilizes a quantitative trend analysis considering both technological and economic indicators for trends and drivers of technology diffusion for 32nm, 22nm, and 14nm logic semiconductor technology. In terms of technological performance, the technology diffusion curve showed an S-curve pattern during the stages of maturity and decline, and the diffusion curve showed evidence supporting the learning curve. The diffusion curve showed the life cycle duration of 2 years, and the rate of technological performance and obsolescence are observed quantitatively between generations. Architectural innovation is affected by technological drivers more significantly than economic drivers. This research has implications as empirical research on the trends and drivers of technology diffusion in the high-tech semiconductor industry, and is meaningful in forecasting new technology adoption or build technology strategy.

• The Korean Journal of Applied Statistics
• /
• v.32 no.1
• /
• pp.69-81
• /
• 2019

We consider bivariate long range dependent (LRD) time series forecasting using a deep learning method. A long short-term memory (LSTM) network well-suited to time series data is applied to forecast bivariate time series; in addition, we compare the forecasting performance with bivariate fractional autoregressive integrated moving average (FARIMA) models. Out-of-sample forecasting errors are compared with various performance measures for functional MRI (fMRI) data and daily realized volatility data. The results show a subtle difference in the predicted values of the FIVARMA model and VARFIMA model. LSTM is computationally demanding due to hyper-parameter selection, but is more stable and the forecasting performance is competitively good to that of parametric long range dependent time series models.