Sensor Network for Pipeline Leakage Detection in Nuclear Power Plant

Wonjune Lee(이원준),Sunghyun Cho(조성현) 대한전자공학회 2017 전자공학회논문지 Vol.54 No.12

원자력 발전소 매설 배관은 시설 노후화로 인한 누수를 피하기 어렵다. 매설 배관의 누수는 경제적 손실 및 인명 피해로 이어질 수 있기 때문에 실시간 누수 탐지 시스템은 매우 중요하다. 기존 전통적인 누수 탐지 시스템은 대부분 누수 탐지 도구등을 활용하여 작업자가 일일이 확인하는 방법이었다. 이에 본 논문에서는 매설 배관 누수를 실시간으로 자동 탐지할 수 있는 센서 네트워크 시스템을 제안한다. 배관의 누수를 탐지하는 기존의 대표적 방법은 두 가지가 있다. 첫 째는 청음봉을 이용한 물리적 방법이고 다른 하나는 배관 양단의 센서로부터 진동 신호를 수신하여 상호상관함수를 계산하여 누수를 탐지하는 방법이다. 그러나 두 가지 방법 모두 실시간에 탐지에 취약하고 전문지식이 있는 전문가가 필요하다는 단점이 있다. 이를 해결하기 위해서 다양한 연구가 진행되었으나 대부분 복잡한 필터링 알고리즘이 필요하여 실시간 시스템에 사용하기에 부적합한 단계이다. 본 논문에서는 앞서 살펴본 문제점들을 해결하기 위해 향상된 누수탐지 방법을 기반으로 한 지능형 센서 네트워크 구조를 제안한다. 제안하는 방법의 성능 분석을 위해 실제 구축한 필드 테스트 및 시뮬레이션을 진행하였다. 시뮬레이션 및 필드 테스트에서는 다양한 형태의 네트워크 토폴로지에 대해 누수 탐지 데이터 전송 지연 및 패킷 전송 성공률 등을 측정하였다. 시뮬레이션 결과 네트워크 그리드 크기가 5 이하일 경우에는 선형 네트워크 구조가 더 유리하였고 네트워크 그리드 크기가 5보다 큰 경우에는 애드-혹 네트워크 구조가 전송 지연 감소에 더 유리함을 보였다. It is important to apply real-time remote sensing system for premature pipeline leakage detection of nuclear power plant because of economic damage and human injury due to leakage. There are two typical methods to detect pipeline leakage. One is the physical method using acoustic rod and the other is cross-correlation method by receiving vibration signals from sensors at both ends. In the former method, it needs a specialist with expertise in listening and is hard to process in real-time. The latter method is greatly vulnerable to noise signals. There are a lot of efforts to solve the limitation. However, most of the methods proposed so far are not suitable for practical systems because those require additional filtering algorithms. The filtering algorithms are difficult to process in real time and thus not suitable for nuclear power plants. In order to solve the above problems, we propose an intelligent sensor network system based on the leakage detection with improved cross-correlation function. For the performance evaluation, we implement the testbed and simulation. The field test and simulation results show that the ad-hoc structure is superior than the linear structure when the grid size is less than 5, whereas the linear structure is more advantageous when the grid size is greater than 5.

Radiographic analysis of the effect of external rotation on the correction angle in reverse step-cut osteotomy for cubitus varus deformity

Wonjune Chang,Sang Won Moon,Dae-Wook Kim,Seok Hahn,Youngbok Kim 대한견주관절의학회 2022 대한견주관절학회 학술대회논문집 Vol.2022 No.4

Aliveness detection based on multispectral analysis for touchless fingerprint recognition

Wonjune Lee,Jungin Lee,Heeseung Choi,Jaihie Kim 대한전자공학회 2010 ICEIC:International Conference on Electronics, Inf Vol.1 No.1

Recently, several researches in touchless fingerprint recognition system has been carried out. However, the touchless system is still vulnerable to spoof attacks by artificial fingerprints. In this paper, we introduce an aliveness detection method with multispectral analysis in touchless fingerprint recognition system. Our fingerprint acquisition device includes green, yellow and red illuminations for capturing the fingerprint images. Multispectral properties, especially reflectance of finger are extracted from the acquired fingerprint images under the each of illuminations. These features which can discriminate between live and fake fingerprint images are used and Support Vector Machine (SVM) is applied to classify live and spoof fingerprint image. In our data set, proposed method achieved 0% EER (Equal Error Rate). The results show that our approach can provide an efficient and effective aliveness detection method in the touchless fingerprint image recognition system.

Decay Heat Estimation of Spent Fuel Assemblies for Decommissioning of Kori Units 3 and 4

Wonjune Mah,Chang-Lak Kim,Sun-kee Lee 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

This paper mainly focuses on the maximum decay heat estimation generated from spent fuel assemblies in the spent fuel pool of Kori units 3&4 at the beginning decommissioning. It is assumed that the spent fuel pool is fully occupied with 2,260 spent fuel assemblies, same as its design capacity. In addition, equally 56.5 spent fuel assemblies have been generated per year. The minimum cooling time is five years considering the transition phase between the permanent shutdown and the amendment of Operating License for decommissioning. Sending and receiving of spent fuel assemblies to/from other units are neglected. Seven representative spent fuel assembly groups are established based on the burnup rate and cooling time. Conservatively high values for the burnup rates and low values for the cooling times are applied. Calculation of the decay heat of each representative group has been performed by using ORIGEN decay solver of SCALE. Then, total decay heat has been calculated based on this. Group 1, 2, and 3 contain comparatively old spent fuel assemblies with 45 GWd/tU burnup rate and 20~30 cooling years. The calculation shows 489~586 watts of decay heat per assembly. Group 4, 5, 6, and 7 contain comparatively new spent fuel assemblies with 55 GWd/tU burnup rate and 5~20 cooling years. The calculation shows 741~1,483 watts of decay heat per assembly. The total maximum decay heat therefore is estimated as 1,609,459 watts.

Repurposing a Spent Nuclear Fuel Cask for Disposal of Solid Intermediate Level Radioactive Waste From Decommissioning of a Nuclear Power Plant in Korea

Wonjune Mah,Chang-Lak Kim 한국방사성폐기물학회 2022 방사성폐기물학회지 Vol.20 No.3

Operating and decommissioning nuclear power plants generates radioactive waste. This radioactive waste can be categorized into several different levels, for example, low, intermediate, and high, according to the regulations. Currently, low and intermediate-level waste are stored in conventional 200-liter drums to be disposed. However, in Korea, the disposal of intermediate-level radioactive waste is virtually impossible as there are no available facilities. Furthermore, large-sized intermediate- level radioactive waste, such as reactor internals from decommissioning, need to be segmented into smaller sizes so they can be adequately stored in the conventional drums. This segmentation process requires additional costs and also produces secondary waste. Therefore, this paper suggests repurposing the no-longer-used spent nuclear fuel casks. The casks are larger in size than the conventional drums, thus requiring less segmentation of waste. Furthermore, the safety requirements of the spent nuclear fuel casks are severer than those of the drums. Hence, repurposed spent nuclear fuel casks could better address potential risks such as dropping, submerging, or a fire. In addition, the spent nuclear fuel casks need to be disposed in compliance with the regulations for low level radioactive waste. This cost may be avoided by repurposing the casks.

무인항공기를 활용한 표적사살의 정당성: 솔레이마니 사살 사례와 대량응징보복 적용

황원준(Wonjune Hwang) 육군사관학교 화랑대연구소 2023 한국군사학논집 Vol.79 No.2

‘국가건설’과 ‘군중’

李沅埈(Wonjune Lee) 중국근현대사학회 2016 중국근현대사연구 Vol.69 No.-

At the end of 1948 when the Chinese Communists(CCP) were on the verge of victory in the long-lasted civil war, they had set about organizing the New Democracy Youth League(‘NDYL’). Though NDYL was basically similar in its functions to other mass organizations established under CCP’s control, it maintained closer relation with the party than any other organizations. It functioned as the main supply route of the party cadres, and although it was formally a mass organization, it was also treated similarly to the party. Based on these features, the NDYL mobilized the youth for the CCP’s ‘New Democracy’ revolution and their nation building projects However, the CCP had put the NDYL under firm control in order to enhance its efficiency in youth mobilization. The NDYL cadres and members were under tight surveillance and they were routinely educated and self-criticized in accordance with the party’s rectification campaign. Although it is true that the party leaders had emphasized the importance of the NDYL’s organizational independence, their limits of independent action was clearly drawn by the party. The NDYL functioned as a useful instrument for the CCP in establishing a firm foundation of party rule in the early period of PRC. Representing the youths’ political and social interests had also been defined as the NDYL’s main obligation, but it is undeniable that it was pushed out of the scene in the course of the CCP’s revolution and nation building strategy.

자동변속기 오일 펌프 성능 향상을 통한 고온, 저속시 라인압 저하 개선

성원준(Wonjune Sung),오종선(Jongsun Oh) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_1

In this study, an oil pump was newly designed to improve the line pressure drop of the middle and large-sized automatic transmission at high ATF temperature and low engine speed condition using optimization technique. Through S/N ratio and mean analysis, the design factors were decided. The newly designed oil pump showed better performance in the view of flowrate and efficiency.

유량 변화에 따른 원자층 증착 장비 내부 유동특성 연구

최원준(Wonjune Choe),홍경표(Kyung Pyo Hong),최예린(Yerin Choi),김문기(Moon Ki Kim),최재붕(Jae Boong Choi),이태린(Tae-Rin Lee),김형근(Hyeongkeun Kim) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11

기혼자들의 성적 평등성이 불륜인식에 미치는 영향과 부부간 성적 자율성의 매개효과

이원준(Wonjune Lee),이희진(Heejin Lee) 한국문화융합학회 2024 문화와 융합 Vol.46 No.1

본 연구의 목적은 기혼 남녀의 '불륜' 인식에 '성적 평등성'이 미치는 영향에 '부부간 성적 자율성'의매개효과, 그리고 성별 및 연령의 조절효과를 밝히는 것이다. 연구자료는 온라인 설문조사를 통해 얻었으며, 표본수는 35-59세 기혼남녀 614명이다. 자료는 Amos와 Mplus를 사용하여 분석하였다. 주요 발견점은 다음과 같다. 첫째, 기혼 남성은 기혼 여성에 비해서 성적 평등성과 부부간의 성적 자율성이 낮고, 불륜에 대해 더 허용적이다. 둘째, 45세 이상의 여성의 경우, 부부간 성적 자율성은 성적 평등성에대한 인식이 불륜에 대한 비판의식을 갖게 하는데 중요한 특성임이 입증되었다. 불륜에 대한 비판의식향상을 모색하는 실천현장의 전문가들은 기혼자들의 성별 및 연령대에 따른 차별성을 반영할 수 있어야 할 것이다. 또한 성적 평등성 인식 개선을 위하여 법률적 제도적 개선과 양성평등 교육강화 등의사회적 노력이 병행되어 나가야 할 것이다. This study aims to reveal the mediating effect of sexual autonomy between couples on the effect of sexual equality on the perception of infidelity among married men and women, and the moderating effect of gender and age. The sample sive of data through online survey was 614 married men and women aged 35-59, analyzed using Amos and Mplus. The notable findings are as follow: First, compared to married women, married men have lower sexual equality and marital sexual autonomy and are more tolerant of infidelity. Second, for women over the age of 45, sexual autonomy between spouses has been proven to be a important characteristic of making the perception of sexual equality critical of affair. Experts in fields seeking to improve critical awareness of infidelity among married people should be able to reflect the discrimination of them according to their gender and age group. In addition, to improve awareness of sexual equality, continuous social efforts, including legal institutional improvement and strengthening gender equality education, must be made in parallel.